Ducati Monster Forum

Moto Board => Tech => Topic started by: BK_856er on September 15, 2008, 08:05:51 PM



Title: 2V belt tension question (!!)
Post by: BK_856er on September 15, 2008, 08:05:51 PM
My M695 is still under warranty, so I'm trying hard to leave the scheduled maintenance to the dealer, in addition to the OCD attention it gets from me.

Recently I had the 7.5k mile service done, and I had my dealer install new belts since the 2yr mark was coming up anyway.

Today I removed the belt covers to rule out some possible sources of a minor oil leak, and gosh those belts felt loose.  Belts are obviously new and the adjuster bolts are tight.  I looked over LTs manual and then watched the Chris K. video.  So a 5mm allen key should get you pretty close to whatever method the dealer would have used, right?  I rotated the motor to align the marks and I can easily fit a 10mm allen between the belt and the (smaller) idler pulley.  Floppy loose all over.

This is WAAAAY too loose, correct?

Seems to run fine.  Bit of a flat spot around 6k since I got it back, but otherwise no running issues.

Comments from the experts??

BK




Title: Re: 2V belt tension question (!!)
Post by: brad black on September 16, 2008, 02:45:40 AM
i always retension new belts on my bikes after 1,000km or so.  they go loose, so you retension them.  usually they're fine after being done once.


Title: Re: 2V belt tension question (!!)
Post by: He Man on September 16, 2008, 08:10:16 AM
that sounds pretty loose, though im not sure if ducati still goes by the same tension they did many years ago. Go back to your dealer and tell them you were inspectng your belts and ask them to recheck them. They use a audio device to record the frequency of the belt when plucked. it could be a bogus belt, or maybe the new specs are just like that. I have a 06 DS1000 and a 5mm is pretty make the beast with two backsing impossible to get through.


Title: Re: 2V belt tension question (!!)
Post by: Speeddog on September 16, 2008, 09:15:34 AM
That's way too loose.


Title: Re: 2V belt tension question (!!)
Post by: BK_856er on September 16, 2008, 09:50:09 AM
Thanks for the input!  [thumbsup]

I could bring it back in, but it's a bit of a hassle.  I think I will take it on myself.

My '07 M695 workshop manual specifies 145Hz (H) and 160Hz (V) using the optical DDS tool, with each respective cylinder at TDC compression.  Each belt has a specific location for the optical measurement.  The manual also indicates to adjust tension when the value falls below 70Hz due to normal wear.

Does anyone know if those frequencies have been updated?  I came across much lower numbers scanning some posts, but I'm not sure if they would apply to my M695.  I'm assuming that the optical (DDS) and audio (microphone) will give an equivalent result.

I think I have everything that I need to measure the frequency with the microphone method.  In their present state, there is insufficient belt tension to hear ANY frequency when plucking the belt.  They just flop.  I also read about a "45 degree twist" test and tried that....I can rotate past 90 degrees!

BK


Title: Re: 2V belt tension question (!!)
Post by: Speeddog on September 16, 2008, 10:06:38 AM
IMO, go for the '5mm allen key tension' and call it good.


Title: Re: 2V belt tension question (!!)
Post by: uclabiker06 on September 16, 2008, 10:39:25 AM
Are they both loose or just one?  I ask because you can use the other one as a gauge.  I think the shop set it loose and then it expanded from use which combined to make it really loose.  Remember the key with belt tensioning is to be in the ball park.  It doesn't have to be very accurate like valve clearance and a lot of other measurements.  Just do your best to get it to the correct tension, retention after 1K miles,  and it'll be fine. 


Title: Re: 2V belt tension question (!!)
Post by: BK_856er on September 16, 2008, 10:55:13 AM
Are they both loose or just one?  I ask because you can use the other one as a gauge.  I think the shop set it loose and then it expanded from use which combined to make it really loose.  Remember the key with belt tensioning is to be in the ball park.  It doesn't have to be very accurate like valve clearance and a lot of other measurements.  Just do your best to get it to the correct tension, retention after 1K miles,  and it'll be fine. 

Both belts were similarly loose, but the vertical belt was a tiny bit tighter.  For the quick check I didn't confirm which cylinder was at TDC compression, I just rotated the crank until the marks lined up.

I probably have about 500-600 miles on the bike since the new belts were installed by the dealer at the 7.5k service.

I will definitely do the 5mm allen key thing first, and then see what kind of frequency it gives me.

BK


Title: Re: 2V belt tension question (!!)
Post by: VeryMetal on September 16, 2008, 06:58:39 PM
They should both be fairly tight. The 5mm allen wrench trick works really well. They will definitely loosen up when you install a new set. The fact that you may not have been at TDC doesn't matter too much, the tension should be pretty similar the whole way round.


Title: Re: 2V belt tension question (!!)
Post by: BK_856er on September 17, 2008, 12:09:36 AM
I set the horizontal tension with a shortish 5mm allen key.  Not quite sure how tough it should be be slide through.  I did "reasonable force with just one hand and little wiggling".

Then I setup the microphone and the free Audacity audio analysis program.  I plucked the belt and recorded the signal at the location specified in the workshop manual (between the crank gear and the MOBILE roller on the lower side).  The spectrum analysis in log scale allowed me to quickly get the primary frequency, which in this case was 117Hz.  I tightened the belt a tad more and got 128-130Hz.  The Ducati spec for my motor is 145Hz on the horizontal belt, but I understand that it would be wise to use less than that.

Changing the measuring location for the horizontal cylinder to the section between the mobile roller and the cam gear gave a value of 103Hz, presumably due to the longer length of belt.

I rotated the crank exactly one revolution and set the vertical belt tension with the 5mm allen key, although this time the allen required just a bit less force to get past the idler.  Per the manual, I recorded the frequency at the length of belt (between the crank gear and the FIXED roller) to give a reading of 125Hz.  The Ducati spec is 165Hz for the vertical belt.  Presumably the higher number is because this length of belt is longer by about 10mm compared to the region measured on the horizontal belt.  For kicks I rotated the crank exactly one more revolution and measured 131Hz.

I'm going to play with things a bit more because I'm still not sure that I have the allen key force down just right.

So far the audio method is uber cool if you're looking for a geeky science experiment, and it's comforting to have a backup technique on hand to quantify things.  It really is easy to collect the audio data and work it up.  Just make sure that you are plucking/recording in the right spot.  More later...

BK


Title: Re: 2V belt tension question (!!)
Post by: brad black on September 17, 2008, 04:01:00 AM
the horiztonal is always tighter than the vertical.  the 1000 had the same spec for both - 145 from memory.  1000 belts won't let you get anything thru at that tension.  the older 620/750/800 belts were 112/124 from memory.  it often does vary every time you turn it over too.


Title: Re: 2V belt tension question (!!)
Post by: BK_856er on September 17, 2008, 09:06:18 AM
Thanks, Brad.

Below is a screenshot of the audio program to give a feel for the data.  The top three traces are individual "plucks" of the belt at three different tensions with the same basic 5mm allen key method, giving roughly 117, 145 and 130Hz from top to bottom.  Generally I would pluck the belt 5-6 times for a given setting with about two seconds between plucks.  The fourth trace is a 130Hz test tone for comparison.  The window in the lower right is a spectrum analysis identifying the peak (frequency) for the 145Hz tension.  The peak frequency from the spectrum analysis was always essentially the same for all the individual plucks.

BK

(http://i35.tinypic.com/17p92w.jpg)


Title: Re: 2V belt tension question (!!)
Post by: mitt on September 18, 2008, 06:21:44 AM
Thanks, Brad.

Below is a screenshot of the audio program to give a feel for the data.  The top three traces are individual "plucks" of the belt at three different tensions with the same basic 5mm allen key method, giving roughly 117, 145 and 130Hz from top to bottom.  Generally I would pluck the belt 5-6 times for a given setting with about two seconds between plucks.  The fourth trace is a 130Hz test tone for comparison.  The window in the lower right is a spectrum analysis identifying the peak (frequency) for the 145Hz tension.  The peak frequency from the spectrum analysis was always essentially the same for all the individual plucks.

BK


I use audacity for "other things"  ;)  I was wondering if it could do freq analysis, or did you use a different program for that?

I have 'helped' my dealer adjust my belts, and the frequency method is variable at best.  Like you said, 1 pluck, 110Hz, the next one 130Hz, etc.  He sort of takes an average of several plucks and calls it good.

But yes, on a 1000DS when adjusted to the 130Hz range, there is no way a 5mm allen is going through.  Maybe a 2mm.

mitt


Title: Re: 2V belt tension question (!!)
Post by: BK_856er on September 18, 2008, 08:03:45 AM
I use audacity for "other things"  ;)  I was wondering if it could do freq analysis, or did you use a different program for that?

I have 'helped' my dealer adjust my belts, and the frequency method is variable at best.  Like you said, 1 pluck, 110Hz, the next one 130Hz, etc.  He sort of takes an average of several plucks and calls it good.

But yes, on a 1000DS when adjusted to the 130Hz range, there is no way a 5mm allen is going through.  Maybe a 2mm.

mitt

Yes, you can get Audacity to do frequency analysis.  I'm no expert (downloaded it just for the belts) but after playing around for a few minutes I found some good tricks.  Just select a waveform after zooming in and do a spectrum analysis from the pull down menu.  Adjust the parameters to log scale and one of the other boxes to 4,000 or something like that.  Move the cursor over the peak and it will snap to the maximum and display the frequency.  This method was very repeatable, even if the waveform looked kinda junky.  The beauty of the recording function is that you can pluck away and see the waveforms in real-time, adjusting your technique as you go, then go back and quickly analyze the best looking ones of the bunch.  I tried the other little non-recording program, and it agreed with my method, but it was very difficult to get a good lock on the signal and I wore out my finger from plucking the belt.

I used the audio method as more of a reality check to make sure that my "5mm allen" setting was in the ballpark.  In the end I used 5mm at the idlers and about 125-130Hz (compression TDC) after rotating a few times.  I can send you some belt waveforms if you want to play around them.

BK


Title: Re: 2V belt tension question (!!)
Post by: howie on September 18, 2008, 07:34:04 PM
We need a current Duc dealer tech to chime in.  Ducati has been gradually reducing the frequency spec on the belts, particularly the 2V 1000.  I'm not sure what the present spec is.


Title: Re: 2V belt tension question (!!)
Post by: scott_araujo on September 19, 2008, 05:56:59 AM
Said already, but yes, they will loosen up after a few miles.  I check mine every few hundred miles until they settle in.

Since I'm sure plenty of people never check them after install at the dealer I'm guessing you can run them fairly loose with not ill effects.  Haven't heard any stories here of a belt jumping a tooth after replacement.  Still, you'd think Ducati would  say to take a look at the tension after a few hundred miles.

Scott


Title: Re: 2V belt tension question (!!)
Post by: bigiain on September 19, 2008, 07:27:17 PM
Still, you'd think Ducati would  say to take a look at the tension after a few hundred miles.

What, and screw with their "half the service costs" advertising campaign?  [cheeky]

big


Title: Re: 2V belt tension question (!!)
Post by: brad black on September 20, 2008, 08:08:55 PM
yeah.

here's the bill for your 20,000km service and you HAVE to bring it back in 1,000km for us to retension the belts. 

at your cost.

what's that you say, another lost customer?

ime, most ducati owners are too governed by cost and the expectation of being ripped off to even contemplate something like this as worthwhile.  they won't be listening as you tell them, they'll just hear another reason why they have to give us money, even if we do say it's good for their bike.

and, after all, no one else does it.  and they must be right.  it's on the internet.


Title: Re: 2V belt tension question (!!)
Post by: ellingly on September 22, 2008, 02:56:08 PM
yeah.

here's the bill for your 20,000km service and you HAVE to bring it back in 1,000km for us to retension the belts. 

at your cost.

what's that you say, another lost customer?

ime, most ducati owners are too governed by cost and the expectation of being ripped off to even contemplate something like this as worthwhile.  they won't be listening as you tell them, they'll just hear another reason why they have to give us money, even if we do say it's good for their bike.

and, after all, no one else does it.  and they must be right.  it's on the internet.
If they sneakily managed to chuck 30 minutes of extra labour onto the original price to the 20k service and said "bring it in in about 1500 km / 1000 miles, and we'll do a free retesnion of the timing belts just to make extra sure they're all happy" then I would be more forgiving. Perhaps even more forgiving if they just ensured their inflated labour rates covered the cost of doing it anyway :).

It is also an excuse to get someone in and go "hey, look, we got that new model, perhaps you'd like to purchase said new motorcycle from us".

Put it another way: if I highly trusted the mechanics, being asked to bring it back in? No worries. I've done it before with my cars. In the case of where I had a timing belt done on a car (which is also italian and has non-self adjusting tensioners), the mechanic said bring it it, it'll take an hour, go sit up in the lunch room and have a beer. Not bad, not bad at all.

Brad: on the trust thing... I have reasons not to trust some mechanics. I should have made a trip to Melbourne and get you to do the 20k service. Go hit the spurs for two days, then come back and get you to retension? :). Guess I'd want to do it midweek, cause as far as I understand the spurs have a few too many cops on them during the weekends these days.

I'm happy to pay good money for good quality service, but it just seems that's very, very hard to get.


Title: Re: 2V belt tension question (!!)
Post by: scott_araujo on September 22, 2008, 05:32:39 PM
All of this is just one more reason to learn to do your own routine maintenance.  Belt replacement and valve adjustment can be a little daunting but setting tension isn't hard, esp on a 2V.  Checking tension is even easier.  Just my 2 cents.

Scott


Title: Re: 2V belt tension question (!!)
Post by: nomadwarmachine on June 10, 2009, 10:48:25 PM
Does anybody have a frequency spec for the horizontal and vertical belt tension frequency at TDC on a 2000 M900?

Also, I have a Mac and am looking for a good program to provide the frequency measurement. Do I use Audacity? Do I need a microphone? 

Thanks!


Title: Re: 2V belt tension question (!!)
Post by: AndrewNS on June 11, 2009, 02:08:42 AM
I've never tried the audio method (and I'm certainly not an expert at anything Ducati), but it seems to me that if you are going to do it this way that it would be important to rotate the crank between measurements to make sure the valve gear is in the same state each time. Is this correct? Just lining up the crank marks for TDC would release the closer spring forces on the horizontal cylinder, but they would still be there on the vertical cylinder, and that would have to give a different frequency reading, wouldn't it?

Also, I read somewhere that it was recommended to use 4/5 mm go/no go allen key test with the 1000DS engines. That would make the belts just slightly tighter than you'd get with the standard 5mm test. I did it this way the last time I adjusted my belts and nothing has broken yet, but I'm curious as to whether I'm out to lunch or not. Anyone know what  those frequencies would test to using the audio method?

   


Title: Re: 2V belt tension question (!!)
Post by: howie on June 11, 2009, 04:24:40 AM
Do what everyone else has been doing for years, 5 mm allen key.


Title: Re: 2V belt tension question (!!)
Post by: woodyracing on June 11, 2009, 05:05:22 AM
I've never tried the audio method (and I'm certainly not an expert at anything Ducati), but it seems to me that if you are going to do it this way that it would be important to rotate the crank between measurements to make sure the valve gear is in the same state each time. Is this correct? Just lining up the crank marks for TDC would release the closer spring forces on the horizontal cylinder, but they would still be there on the vertical cylinder, and that would have to give a different frequency reading, wouldn't it?

Also, I read somewhere that it was recommended to use 4/5 mm go/no go allen key test with the 1000DS engines. That would make the belts just slightly tighter than you'd get with the standard 5mm test. I did it this way the last time I adjusted my belts and nothing has broken yet, but I'm curious as to whether I'm out to lunch or not. Anyone know what  those frequencies would test to using the audio method?

   

your supposed to lock the cams and crankshaft in place using the Ducati tools and on most bikes you loosen the 3 bolts on each cam gear to allow movement without changing cam timing so that when you tension the belts it tensions the belt all the way around

ALSO 130+Hz is NOT the Ducati spec for belt tension!  That spec was intended for degreeing the cams instead of clarifying it in the manuals Ducati sends out a service bulletin to the dealers (often) reminding us that all bikes are to be set at 110Hz for new belts and 90-100Hz for used belts. 


Title: Re: 2V belt tension question (!!)
Post by: Langanobob on June 11, 2009, 07:46:17 AM
Quote
your supposed to lock the cams and crankshaft in place using the Ducati tools and on most bikes you loosen the 3 bolts on each cam gear to allow movement without changing cam timing...

Could be that my creative visualization technique is off this morning but it seems to me that loosening the three bolts and allowing relative movement between the cams and the cam gears is gonna change your cam timing. 

Edit:  OK, I think I see now, after adjusting the belt tension with loose bolts, you have to go back and reset the cam timing.


Title: Re: 2V belt tension question (!!)
Post by: EEL on June 11, 2009, 09:04:53 AM
Personally, for all the non DS motors I've tensioned, I've always used 5mm on the horizontal and 5.5 mm on the vertical. I havent had any issues for the 35k miles I've had on my monsters. I probably should go back and retension them after 1k but I'm too lazy and never get to it.

That being said, when I do take them off, the tension seems to be Ok..

If you tension them too tight you'll have bearing failures on the rollers.


Title: Re: 2V belt tension question (!!)
Post by: nomadwarmachine on June 11, 2009, 10:11:53 AM
How tight should the Allen key fit between the belt and roller? Should I not be able to get the next size in there?


Title: Re: 2V belt tension question (!!)
Post by: scott_araujo on June 11, 2009, 10:31:39 AM
There should be some resistance.  I like to be able to slide it through from one side to the other without significant force.  You certainly shouldn't be grunting, holding your breath, or wrestling the key with two hands.  Getting the next 1mm+ size through should be very difficult comparatively but it's not impossible.

And remember, a little too loose is better than a little too tight.

Scott


Title: Re: 2V belt tension question (!!)
Post by: BK_856er on June 11, 2009, 10:41:47 AM
How tight should the Allen key fit between the belt and roller? Should I not be able to get the next size in there?

I struggled with the same question.  Take a look at the belt change video Chris K. made for a good perspective on it.

I should update this old thread with a link to the more recent thread where the current recommended belt frequencies were confirmed....

GOOD STUFF -->  http://ducatimonsterforum.org/index.php?topic=18964.0 (http://ducatimonsterforum.org/index.php?topic=18964.0)

BK


Title: Re: 2V belt tension question (!!)
Post by: woodyracing on June 11, 2009, 04:29:09 PM
Could be that my creative visualization technique is off this morning but it seems to me that loosening the three bolts and allowing relative movement between the cams and the cam gears is gonna change your cam timing. 
think about it a second.  Cams locked in place, crankshaft locked in place.  Those locks don't come off until the belts are installed and tensioned.  You have a tensioned belt and where exactly are the camshafts and crankshaft?
 in the EXACT same position in perfect time (as perfect as you can get without degreeing the cams at least)


Title: Re: 2V belt tension question (!!)
Post by: howie on June 11, 2009, 08:03:22 PM
How tight should the Allen key fit between the belt and roller? Should I not be able to get the next size in there?

Until you develop the correct feel make sure a 4 mm. allen goes through real easy and a 6 mm is real tight.  You should now have a light drag with a 5 mm.  As Scott said, better to err on the side of loose.


Title: Re: 2V belt tension question (!!)
Post by: AndrewNS on June 12, 2009, 01:12:58 AM
I understand exactly what woodyracing is saying, and it would be the real deal...probably the only way to get consistent audio readings between the two belts as well. It would probably give the best results even when using the allen key method 'cause the cam timing would set correctly after each adjustment, and that would be going off as the belts stretch in normal use. But it is a bit of a ITA, especially for someone like me who lacks the correct tools to lock everything in place. Not meaning to derail this thread, but how much do the locking tools cost? Could you make some?

Not like I think you'd get much return on this, but I sorta like the thought of doing things precisely when I can (within reason).


Title: Re: 2V belt tension question (!!)
Post by: howie on June 12, 2009, 05:22:32 AM
The correct tool can be made from a screw.  I don't remember the size.  The rubber piece behind the cam pulley has a screw in it.  Remove this screw and get one long enough to do the job.


Title: Re: 2V belt tension question (!!)
Post by: scott_araujo on June 12, 2009, 06:04:12 AM
Not like I think you'd get much return on this, but I sorta like the thought of doing things precisely when I can (within reason).

So you set it precisely then start the engine and get different parts of it to somewhere between 200 and 1000 degrees.  The belts get hot too.  They stretch, they settle, they're not perfect so they are just a bit tighter at one spot in their rotation than in another.  Of course there's the whole debate as to whether the vertical runs a little hotter since it's out of the air stream.  Did you set them differently or the same?  Some people set them the same some set the vertical a little looser and no one seems to have problems.  Then you ride, turn it off, and let it cool.  You do this between dozens and hundreds of times over the next little while until you change the belts again.  Most people don't check the belts between changes and they certainly don't both stretch or settle in the same, yet again, no one really seems to have any problems.

I'm not trying to be a jerk here at all or criticize.  Good maintenance is a good thing.  What I'm saying is that it's not rocket science, it's not all that critical.  Setting your belts to proper tension is a good thing but there is an acceptable range and it's fairly easy to hit.  The usual stress and vast temperature swings of an air cooled engine just running will play havoc with your settings immediately.  It probably matters more for 4V bikes with higher tension and tighter tolerances.  For a 2V just make sure they are not too tight so you don't stress the seals and bearings.

Also, you can do this and much more :)  Ducati maintenance is not that hard.  Doing your own work can be one of the most satisfying parts of owning any motorcycle.

Scott


Title: Re: 2V belt tension question (!!)
Post by: AndrewNS on June 12, 2009, 08:24:35 AM
I certainly agree with you about people making way too much out of all this "belt tension" stuff - it's sort of like a Ducati-specific version of the oil threads that run endlessly on other boards [laugh].

On the other hand though, those belts do stretch, and when they do the slack is taken up by a movable tension roller on one side. Just trying to visualize this in my mind's eye, if you had 1/4 inch of belt stretch (which seem reasonable) and it resulted in that much motion around the cam pulleys from a reference position I'm guessing that would be what, maybe 5 - 10 degrees of rotation?

I don't know if that's enough to make a noticeable difference in the way a bike would run, but it seems like it should. Just thinking out loud here - anyone can feel free to correct me if I'm wrong.....I should duck now...     


Title: Re: 2V belt tension question (!!)
Post by: Speeddog on June 12, 2009, 09:05:30 AM
1/4" of belt stretch would be *huge*.
That would be 1/8" per 'run'.
4-valve pulleys are 18 tooth, 8mm pitch IIRC.
So that would be about 8 degrees of change in cam timing.
That would cause a noticeable change in how the bike ran.

scott_araujo pretty much summarized it in his last post.

The belts are made from some variety of rubber with kevlar 'string' to carry the load.
The kevlar isn't going to stretch much at all.
The teeth will compress and take a set over time, due to the heat and load.
And they'll wear down a bit, that's where the rubber 'dust' you see inside the belt covers comes from.
So, that's where the slack will come from.
I've seem 'em gain about 2mm of clearance over 5000 miles or so, meaning that belts set to 5mm at the tensioner end up at 7mm.

I haven't seen any outright belt failures.
I've seen a couple of belts very close to failure from seized tensioner rollers.
 


Title: Re: 2V belt tension question (!!)
Post by: scott_araujo on June 12, 2009, 09:41:11 AM
My first set of belts stretched A LOT.  I put them on at proper tension and rode 1400 miles to get home.  When I checked them on arriving they were WAY loose, not skipping a tooth but close.  This second set hasn't stretched so far but it's only been a few hundred miles.  Now I check them every few hundred miles after a new install until they settle, then at every oil change.  It only takes a few minutes, 10 seconds if you leave the covers off.  As mentioned, checking that the rollers aren't frozen is just as important if not more so.

Scott


Title: Re: 2V belt tension question (!!)
Post by: ollie on March 25, 2011, 08:00:26 PM
Bringing this one back from the dead.

My belts are due for replacement, it's been about 2.5 years sinece they were done last, by the last owner.
 I pulled the covers off to take a look at the condition of them and noticed they are way loose. Was expecting the tension to be around the  the 5mm allen key mark, but at the moment I can fit a finger through, if I try hard enough I could possibly slip the belt off the tensioner wheel!!!

Bike has been running fine, with no noticible issues. What should I do?
 - Tension them  up myself before I start it again- I've never done this before but have watched the vid on you tube and It seems easy enough
 - just ride the bike to the mechanic and get the belts changed - bit nervous now after seeing how loose they are.


Obviously, these are way, way out of spec - could this have caused any issues I should be aware of, or with timing belts it's either Ok or really really bad, with no inbetweens??


Title: Re: 2V belt tension question (!!)
Post by: ducpainter on March 25, 2011, 08:05:48 PM
Bringing this one back from the dead.

My belts are due for replacement, it's been about 2.5 years sinece they were done last, by the last owner.
 I pulled the covers off to take a look at the condition of them and noticed they are way loose. Was expecting the tension to be around the  the 5mm allen key mark, but at the moment I can fit a finger through, if I try hard enough I could possibly slip the belt off the tensioner wheel!!!

Bike has been running fine, with no noticible issues. What should I do?
 - Tension them  up myself before I start it again- I've never done this before but have watched the vid on you tube and It seems easy enough
 - just ride the bike to the mechanic and get the belts changed - bit nervous now after seeing how loose they are.


Obviously, these are way, way out of spec - could this have caused any issues I should be aware of, or with timing belts it's either Ok or really really bad, with no inbetweens??

You could adjust them and then take it to the mechanic.

If nothing bad has happened yet then no damage has been done. It is really...really bad when it goes wrong.


Title: Re: 2V belt tension question (!!)
Post by: ollie on March 25, 2011, 08:13:31 PM
Thats a relief, I'll have a go a tensioning them before taking it in to get new belts

How could they have got so loose - new belts were last done at the local dealership. I wouldn't have expected belt wear to be this much, especially seeing as though the km's are still below change over specs.



Title: Re: 2V belt tension question (!!)
Post by: Speeddog on March 25, 2011, 09:02:04 PM
Bringing this one back from the dead.

My belts are due for replacement, it's been about 2.5 years sinece they were done last, by the last owner.

~~~SNIP~~~

Do you have a service receipt showing a belt change or was it just what the last owner *said*?



Title: Re: 2V belt tension question (!!)
Post by: speedknot on March 25, 2011, 10:08:10 PM
WTF?  Using a frequency analyzer to adjust belts?  I thought the Germans liked to over engineer their shit.  Like some have said, go for feel or the 5mm allen method. 
While at the dealer someone mentioned that they use a tuning fork to adjust the valves.  Is this true?  What ever happened to two wrenches and a feeler gauge?  I'm freakin lost!


Title: Re: 2V belt tension question (!!)
Post by: ollie on March 25, 2011, 10:23:50 PM
Do you have a service receipt showing a belt change or was it just what the last owner *said*?



yup, got a service receipt for the replacement of the belts - there is a note the bottom that indicates that the first set of belts that were replaced were too tight  [roll]


Title: Re: 2V belt tension question (!!)
Post by: ducpainter on March 26, 2011, 10:33:19 AM
WTF?  Using a frequency analyzer to adjust belts?  I thought the Germans liked to over engineer their shit.  Like some have said, go for feel or the 5mm allen method. 
While at the dealer someone mentioned that they use a tuning fork to adjust the valves.  Is this true?  What ever happened to two wrenches and a feeler gauge?  I'm freakin lost!
The 5mm wrench method doesn't work for the DS or 4V.

I guess the 450 twist method can be used if you have a feel for it.


Title: Re: 2V belt tension question (!!)
Post by: chris1044 on March 27, 2011, 04:27:25 PM
WTF?  Using a frequency analyzer to adjust belts?  I thought the Germans liked to over engineer their shit. 

At least the Germans engineer their shit...from all the posts I've read on this topic, it sounds like Ducati Engineering forgot that the timing belts load the cam bearings when the engine is spinning, and under-engineered them.  That's why they have this fancy tuning method.

On a moto-GP bike, OK, fine.  But on a bike that's going to be sold to the masses and not serviced/done by a DIY????   [laugh] Someone surely got a promotion for this....


Title: Re: 2V belt tension question (!!)
Post by: gr1976 on March 27, 2011, 05:04:08 PM
I did mine on my s2r1000 and it was much easier than I thought. I watched the CA Cycleworks vid and attempted to use the tuner they suggested on my laptop, but it was to sensitive no matter how I adjusted my audio input. I downloaded several tuners but found this online one to be the best.

http://www.seventhstring.com/tuner/tuner.html (http://www.seventhstring.com/tuner/tuner.html)

set each  belt to 103Hz...so far so good


Title: Re: 2V belt tension question (!!)
Post by: hackers2r on March 29, 2011, 07:30:24 AM
I am thoroughly confused.  When reading the Ducati service manual for my S2R 800, it clearly states in "checking and adjusting timing belt tension" that the correct frequencies are 145 and 160 hz for the hor and ver cylinders respectively.  I've been going by the 5mm key for a very long time but decided to mess with some harmonic tuners and they were way tighter than the 5mm key method.  Do the S2R 800s have tighter belt tensions than other 2v?  I can't find anything going against the frequencies stated here in the workshop manual.  Thanks.


Title: Re: 2V belt tension question (!!)
Post by: Slide Panda on March 29, 2011, 07:42:42 AM
I'm not a expert in the matter - but it seems that the harmonic spec is a more recent invention. Older tech manuals called for a tool that was basically a spring scale you pressed onto the belt at a specific spot, did some mumbo jumbo and got it about right. While it seems a bit fancier than an allen key feeler, it's not that much different at the end of the day.  With a harmonic device, you don't need to put it in the right spot as much and you're letting a computer do the measuring. But back in 'the day' you couldn't whip out your smart phone and measure the frequency - so that sort of measurement wasn't as accessible (and cheap) is as it today.


Title: Re: 2V belt tension question (!!)
Post by: seevtsaab on March 29, 2011, 07:47:02 AM
.... But back in 'the day' you couldn't whip out your smart phone and measure the frequency ....

you mean .... there's an app for that?


Title: Re: 2V belt tension question (!!)
Post by: Slide Panda on March 29, 2011, 08:06:06 AM
you mean .... there's an app for that?

Several.

Free
http://www.gibson.com/en-us/Lifestyle/Features/geek-out-five-essential-819/ (http://www.gibson.com/en-us/Lifestyle/Features/geek-out-five-essential-819/) - run a search in the app store - I couldn't sus up a link real fast
Pay
http://itunes.apple.com/app/tuna-pitch-chromatic-tuner/id313492710?mt=8 (http://itunes.apple.com/app/tuna-pitch-chromatic-tuner/id313492710?mt=8)
http://itunes.apple.com/app/stay-in-tune-chromatic-tuner/id285403537?mt=8 (http://itunes.apple.com/app/stay-in-tune-chromatic-tuner/id285403537?mt=8)


Title: Re: 2V belt tension question (!!)
Post by: ducpainter on March 29, 2011, 09:26:23 AM
I am thoroughly confused.  When reading the Ducati service manual for my S2R 800, it clearly states in "checking and adjusting timing belt tension" that the correct frequencies are 145 and 160 hz for the hor and ver cylinders respectively.  I've been going by the 5mm key for a very long time but decided to mess with some harmonic tuners and they were way tighter than the 5mm key method.  Do the S2R 800s have tighter belt tensions than other 2v?  I can't find anything going against the frequencies stated here in the workshop manual.  Thanks.
They didn't change anything on the design.

If you go with the factory spec your pulleys will be noisier and wear/fail sooner.

The machine Ducati uses is much more than a frequency checker. It also does the actual 'plucking' of the belt. They do it this way to get repeatable results in manufacturing. You can vary the results when plucking by hand easily.

Stick with the 5mm hex method for your 800 2V and be happy. ;)


Title: Re: 2V belt tension question (!!)
Post by: BK_856er on March 29, 2011, 09:52:09 AM
I am thoroughly confused.  When reading the Ducati service manual for my S2R 800, it clearly states in "checking and adjusting timing belt tension" that the correct frequencies are 145 and 160 hz for the hor and ver cylinders respectively.  I've been going by the 5mm key for a very long time but decided to mess with some harmonic tuners and they were way tighter than the 5mm key method.  Do the S2R 800s have tighter belt tensions than other 2v?  I can't find anything going against the frequencies stated here in the workshop manual.  Thanks.

Careful...Ducati revised the belt frequency spec on the M695 (and probably others) to something much lower.  See pg2 of this thread for info and a link to yet more info.

BK


Title: Re: 2V belt tension question (!!)
Post by: hackers2r on March 29, 2011, 10:01:32 AM
Done and done...just confirmed this and retensioned to 110 hz.


Title: Re: 2V belt tension question (!!)
Post by: Slide Panda on March 29, 2011, 10:04:09 AM
Stick with the 5mm hex method for your 800 2V and be happy. ;)

Yeah - now I'm remembering a wave of issues that cropped up on the S2R 1000, (and probably) 800 when they first hit the scene. The belts were too tight and causing the pulley bearings to burn up and seize. The very simple solution was looser belts.

5mm it is!


Title: Re: 2V belt tension question (!!)
Post by: gr1976 on March 29, 2011, 10:43:00 AM
I am thoroughly confused.  When reading the Ducati service manual for my S2R 800, it clearly states in "checking and adjusting timing belt tension" that the correct frequencies are 145 and 160 hz for the hor and ver cylinders respectively.  I've been going by the 5mm key for a very long time but decided to mess with some harmonic tuners and they were way tighter than the 5mm key method.  Do the S2R 800s have tighter belt tensions than other 2v?  I can't find anything going against the frequencies stated here in the workshop manual.  Thanks.

I got my belts from CA Cycleworks. The packaging states to tune between 99 Hz and 110 Hz for the S2R 1000. I got very repeatable results using the online tuner I mentioned above and the "pluck point" shown in the service manual. I aslo used a thick 2" washer that had smooth edges to pluck the belt as I was having trouble plucking it hard enough with my fingers.


Title: Re: 2V belt tension question (!!)
Post by: bikepilot on March 29, 2011, 02:14:35 PM
I checked the tension on the wife's 620 and found the belt rather loose.  An 8mm key slipped through with no effort.  I snugged them up so that a 6mm slipped through with moderate effort and a 5mm slipped through fairly easily.  Supposedly it had new belts within the last 1k miles, but they don't look all that new to me so I'm putting on new ones for peace of mind very shortly, just need to order them up :)  Someone has been into the valves very recently though as several of the inspection cover bolts are clean and shiny while most were grungy.



Title: Re: 2V belt tension question (!!)
Post by: Armor on March 29, 2011, 05:49:15 PM
I have found when I replace the belts on my M1000, the bike runs noticeably better.  I attribute this to tight belts verses the loose old belts affecting the cam timing.  I think this is why Ducati specifies tight belts, at least on the DS motors.  Too tight and you can ruin the tensioner bearings, too loose and you lose performance.  That is why you check harmonics to get it just right.


Title: Re: 2V belt tension question (!!)
Post by: ducpainter on March 29, 2011, 06:01:10 PM
They run much better with proper valve clearances, rather than the cost based new tolerances...

than they ever would with harmonically adjusted belts.

Just sayin'.


Title: Re: 2V belt tension question (!!)
Post by: KRJ on March 29, 2011, 08:02:01 PM


 It's a shame We have to go through all this "harmonic" belt tensioning process, it's like Harley setting up steering head preload with a string, pully and weights!!  There has got to be a static adjustment at ambient temp.to set the belts?  Or You just poke and hope, kinda' like pull out and pray...I have seen some Dealer set belts that were very tight at operating temp.  Wish We could find a positive setting that works, without the drama and guesswork. just sayin' , [roll]


Title: Re: 2V belt tension question (!!)
Post by: Armor on March 30, 2011, 08:27:19 AM
The FIM banned Aprilla from using gear driven cams because the bikes were much faster than the stock chain driven cams.  I couldn't believe how much better my bike ran when I replaced my belts last summer.  I used a program that gives a digital readout for the frequency.  It was pretty easy to use.


Title: Re: 2V belt tension question (!!)
Post by: scott_araujo on April 01, 2011, 06:51:34 AM
They run much better with proper valve clearances, rather than the cost based new tolerances...

than they ever would with harmonically adjusted belts.

Just sayin'.

+1.  Go to the old spec.  I set my valves to the old spec and my belts with and allen key.

Also, I've seen brand new belts loosen considerably after 1000 miles or so.  Check often.

Scott


Title: Re: 2V belt tension question (!!)
Post by: Langanobob on April 01, 2011, 10:45:23 AM
The FIM banned Aprilla from using gear driven cams because the bikes were much faster than the stock chain driven cams.  I couldn't believe how much better my bike ran when I replaced my belts last summer.  I used a program that gives a digital readout for the frequency.  It was pretty easy to use.
Don't have all the facts (of course) but I don't think the Aprilia gear driven cams were banned solely because the engines were faster.  I think they were banned because they were faster and the cam gear drives were not homologated on stock street bikes.  If Aprilia had sold the gear drives  as original equipment on enough stock street bikes (150?) they would've been within any reasonable interpretation of the rules and would be allowed.

But regardless if my view above is correct or not,  it's interesting that the gear cam driven engines were significantly faster.

Bob


Title: Re: 2V belt tension question (!!)
Post by: bigiain on April 02, 2011, 10:22:04 PM
Also, I've seen brand new belts loosen considerably after 1000 miles or so.  Check often.

I don't know that they need checking "often", but checking them at least once ~1000miles after setting them is certainly a good idea.

(Has anybody ever needed to retention them more than once between fitting them and replacing them on schedule?)

big


Title: Re: 2V belt tension question (!!)
Post by: scott_araujo on April 03, 2011, 02:55:22 PM
I usually check around 1000 and tighten up a bit.  No other checks have needed tightening so far.  I check often because my first set of belts got so loose they looked like they were going to skip a tooth.  Only takes 10 minutes to check.

Also, it begs the question of how critical tension is.  Most people get them put on and never check again until it's time to change them.  They're going to loosen up at least a little which means no matter how perfect the tension was it's off after 1000 miles or so until you replace them again.  4V seems more critical but setting 2V belts doesn't need to be rocket science.

Scott


Title: Re: 2V belt tension question (!!)
Post by: ducpainter on April 03, 2011, 03:08:51 PM
I usually check around 1000 and tighten up a bit.  No other checks have needed tightening so far.  I check often because my first set of belts got so loose they looked like they were going to skip a tooth.  Only takes 10 minutes to check.

Also, it begs the question of how critical tension is.  Most people get them put on and never check again until it's time to change them.  They're going to loosen up at least a little which means no matter how perfect the tension was it's off after 1000 miles or so until you replace them again.  4V seems more critical but setting 2V belts doesn't need to be rocket science.

Scott
Everyone checks tension cold, because that is where the spec is given.

Have you ever re-checked a belt that is loose cold, when hot?

I still maintain that as long as the belts aren't so loose that they can skip when cold or so tight they make the tensioners scream when hot, it's all good.

Valve clearance is much more important to proper running.


Title: Re: 2V belt tension question (!!)
Post by: vaclav on April 03, 2011, 06:44:25 PM
Did anybody who did the frequency thing with a DS1000 engine ever go back and slip some allen wrenches through to see what it worked out to?


Title: Re: 2V belt tension question (!!)
Post by: KRJ on April 03, 2011, 08:11:22 PM


   Awsome, the $20.000 question...an ambiant temp. static, manual adjustment, replicating the proper harmonic method.... [thumbsup]


Title: Re: 2V belt tension question (!!)
Post by: Langanobob on April 04, 2011, 06:49:15 AM


...Valve clearance is much more important to proper running.

Valve clearance affects the valve opening and closing time.  Also the total valve opening amount or height, but I'm thinking that a thousandth of an inch or two are not going to be noticeable on a street bike, but maybe they are.   Loose belts also affect the valve opening and closing time.   It seems to me that it's equally important to have both properly adjusted.   It "seems" that loose belts would have even more effect on valve timing than a slightly maladjusted valve clearance, but I don't know that for sure.



Title: Re: 2V belt tension question (!!)
Post by: ducpainter on April 04, 2011, 07:51:59 AM
Valve clearance affects the valve opening and closing time.  Also the total valve opening amount or height, but I'm thinking that a thousandth of an inch or two are not going to be noticeable on a street bike, but maybe they are.   Loose belts also affect the valve opening and closing time.   It seems to me that it's equally important to have both properly adjusted.   It "seems" that loose belts would have even more effect on valve timing than a slightly maladjusted valve clearance, but I don't know that for sure.


Put it back into context.

Have you ever checked your belts when hot after you determined that they were loose cold?


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