Belt tension Allen key?

[greenmonster]

If you set belt tension on a 1000/1100 engine with the sonic method,
which Allen key size fits between belt tensioners?

[Buhgaboo]

The subtleties in adjusting in accordance to a harmonic are so slight it's almost comical thinking there's a shortcut...but...the belt isn't going anywhere and if it's a bit too tight your going be annoyed into loosening it up anyway

Just get a guitar tuning app...rotate the engine so the cams are free and start strumming like your warming up for a desmo concerto

[rule62]

5mm horizontal, 6mm vertical  same as all the others. Done it both ways on 620, 1000ds, and 1100.

[koko64]

1000/1100 motors .

Rear 4mm Allen key.
Front 1mm feeler gauge. ☆

The belt pulley locations are not symmetrical between cylinders compared to the smaller motors.

☆ Some give a little more on the front like 2mm on a feeler gauge. It may depend on your feel and how strong your hands are. Developing arthritis has probably made me more accurate

Then I twist the belts for that 45 deg twist test, then I warm the bike up and note how much tighter they get with thermal expansion of the motor (more than you think). I do this double and triple checking due to not having the Harmonic tensioner.

As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a pulley or snap a belt.

I use LT Snyder's, bikeboy's and Speeddog's specs.

[greenmonster]

Did some measurements last night w new belts.
Gates Carbon Drive app no readings, PanoTuner worked ok.
Hard to get consistent results f sure.
The issue when comparing Hz-Allen is snugness me think, f e medium snug 2mm is a
little tighter snug on 3mm, too inconsistent to get repeatable result etc. You simply cannot say f e 3mm Allen equals X Hz.
Think I`ll go w koko`s advice from another thread about 1100 engines
and set 3mm HZ & 4mm VE. Snug.

[koko64]

I tend to use Exactfit belts and oem. I often set on the looser side of good, if you get my drift. The belts really do tighten up a lot on a hot motor.

[Armor]

Rent a harmonic tensioner from ducatitoolrental.com.  Easy to use and get correct tension.  No guessing.

[ducpainter]

Rent a harmonic tensioner from ducatitoolrental.com.  Easy to use and get correct tension.  No guessing.

Not so easy for some of our overseas members.

[koko64]

As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a bearing or snap a belt.
 

[DuciD03]

1000/1100 motors .

...Then I twist the belts for that 45 deg twist test, then I warm the bike up and note how much tighter they get with thermal expansion of the motor (more than you think). I do this double and triple checking due to not having the Harmonic tensioner.

As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a pulley or snap a belt.

I use LT Snyder's, bikeboy's and Speeddog's specs.

put  a couple of new sets of cam belts on an 800 and 1K ds; as you know not good to overly tighten belts. Initially using the Allen key method; checking to see that the "As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a pulley or snap a belt."

Using the 45 deg when hot method; check and see how snug; then just loosen the tensioner and tighten the tensioner to on the loose side of snug while still hot (while minding the hot exhaust pipe ... )

... let me know if I'm missing something in that thinking.

did try plucking the belts and listening to the harmonics; I in fact spent a lot of time plucking the belts, listening, thinking um-ming and scratching my head, chasing my tail, ... and went with the above.

[koko64]

What readings did you get?

Did you use the 5 & 6mm Allen key method on the 800 and 4mm & 1-3mm method on the 1000?

Some thoughts. Do you pull the belt away from the pulley a little when passing the Allen key through or just push it through? How heavy handed are you? How much force do you use and how much drag do you feel? Also I  have found the Exactfit belts more supple and the oem a little stiffer to handle. It's a bit like adjusting valves, you develop a feel and confidence over time. Honestly, there many belts out there adjusted a bit too tight or a little loose and working fine and while it does effect cam timing, how many bikes come from the factory with perfect timing?

Some people will get a shock when they check the belt tension on a hot motor. It explains why the factory changed its tension specs on the 1000/1100 models. So while it's easier on the 400-900 models, I spend twice the time setting the tension on 1000/1100 models. I thought about buying the tool, but I think like with any tool or equipment, the operator is still a factor.

[MonsterHPD]

I have used the "proper" harmonic tester on the 1100 motor a cople of times (borrowed from a friend) and was surprised at how tight the belts were adjusted to the recommended frequency. Nowhere near any allen key test gap as I remember it.
I think next time I'll adjust the belts tight on a warm motor with the cams free, and see how that feels when the motor is cold.
Judging from the big difference you can see in belt tension on motors depending on how long since they were adjusted, and who adjusted them, etc, there seems to be quite a wide window before anything bad happens.
I'm not trying to say it's not important, but within sensible limits it seems to work quite well, nothing to lose sleep over. Beeing consistent and keeping track of the status is key for me.

[DuciD03]

What readings did you get?

Did you use the 5 & 6mm Allen key method on the 800 ....?

Some thoughts.....just push it through? heavy handed;

.... Honestly, there many belts out there adjusted a bit too tight or a little loose and working fine and while it does effect cam timing, how many bikes come from the factory with perfect timing?

Some people will get a shock when they check the belt tension on a hot motor.

above is generally what I did with a 5mm both cam belts on a 800 ... 1ks different; when I had it in for an expert mechanical tune after a rebuild; the expert mechanic race tuner mentioned he thought the belts were loose on the old where I had them set; I remember fussing with this; think it was 5mm / check while hot method. I gave him new belts he installed never second guessed him. Bike ran way better after he tuned it; expensive service but worth piece of mind.

Harmonic tension is that elusive quirky Duc thing that if you don't do this all the time; I think its easy to F up. Wouldn't recommend to a back yard mechanic; even if you can tune a guitar (I can harmonically tune a guitar no problem; very accurate when you get the hang of it).

[koko64]

Sorry if I expressed myself poorly. I set the belt tension cold, I finger check them hot for some "give" to not stress the belts or bearings. So the Allen key setting is cold. The 6mm is to not fit but the 5mm goes thru on the 400-900 bikes. The 5mm goes thru then the 6mm should not go thru, if it does the belts are too loose.

I'm quick with my own bikes but double and triple check customer bikes.

[MonsterHPD]

I'm quick with my own bikes but double and triple check customer bikes.

Except for the customer bike bit (I don 't have any), I'm the same :-)