Another no-Monster build thread

[MonsterHPD]

Track day done, eventual success, it seems. But not straight away.

The first stint gave the same results as last time: Clutch slips.
Since the weather was very uninspiring, I decided to embark on a step-by-step problem investigation, even if some steps seemed like chasing foregone conclusions.

Second stint: With the spring from my old STM clutch, used on my old M900 for years without problems. It´s marked "150 kg" as opposed to the "slippers" 160 kg spring. Presumably, these numbers have some relation to the stiffness of the spring; if this would work, the 160 kg spring is faulty.
Well, it did not work. I suppose beeing able to activate the rev limiter just by turning the twistgrip a few more degrees could have some bright aspects if accompanied by some effects like accelleration, tire spin, wheelying.... but not when nothing happens. Obviously, the 160 kg spring is not the culprit.     

Third stint: Having anticipated something like this after after the problem first appeared, I had ground a steel plate down slightly, from 1.5 to 1.2 or so mm, in case I might need something other than 1.5 or 2.0 mm. I installed one this extra steel disc next to the pressure plate, with the 160 kg spring. This throws clutch package thickness over the STM max limit, but what the hell ... and it worked.

Due to weather, crashes, etc, the 3rd stint was actually the last stint of the day. I´m also working on a very abrupt throttle response going from engine brake to slight throttle opening; and the bike demands beeing ridden almost hands off, but on the laps when I managed to get everything (including myself) working, it´s really nice to ride. And no clutch slippage this stint.

Suspension still seems a bit stiff, but I need a bit more speed and decent riding before I can judge on that. Next track excursion is last week of june at Gotland Ring on the isle of Gotland in the baltic sea. Hopefully, 4 consecutive track days will bring some progress.           
       

[Speeddog]

Did the clutch slip when it was supposed to slip?

[MonsterHPD]

Yes, the back-torqe slip function seened to work quite OK. I'll need more than that one stint to know exactly.

[Howie]

A good shop might have a spring tension tool  https://www.benchmarkarizona.com/rimac-valve-spring-tester-used_8_83_252.html   You would need to know the correct compressed spring height for the test. Maybe STM can supply specs.  My experience is usually if they are bad they will not sit square.  Or, if all functions fine, just leave it.

[MonsterHPD]

I think I leave it for now ... but I´ll order a spare, and bring the clutch toolkit to the track days.

I´ll see if I can use my suspension spring tester for these springs as well, at least a comparative measurement could be possible. Another little miniproject   

[Speeddog]

Perhaps the secondary spring is cracked?

[MonsterHPD]

Perhaps the secondary spring is cracked?

No, this clutch has the spider type secondary spring, and it´s ok.

On the M900, with the old STM cluth, I ha a cracked main spring once, but did not notice until I dismantled the clutch in the winter season. or maybe it acted a bit funny, don´t remember really, but at least no bad enough for me to start looking what was going on.   

[MonsterHPD]

I had some money on my Paypal account from the sale of my Radical stuff ... can´t have that 

Got some new carbon instad:

20170618_142019 by torbjörn bergström, on Flickr

[koko64]

 
It looks the business now.

[MonsterHPD]

Hello everyone, long time no hear… so I figured an update could be of interest.
It´s been 8 track days since last, and there has been some developments.

First excursion was the 4 days at Gotland Ring, a really nice track but awkward to reach due to it´s location. First day started off pretty well; I haven’t been to the track for two years so some re-familiarization was necessary. Things seemed to work pretty much OK, until halfway thru day one the clutch started slipping again.  I had prepared for this and brought everything I needed to put in a stock clutch, so that´s what I started to do. When disassembling the STM, this is what I found:

20170626_162628 by torbjörn bergström, on Flickr

The spider spring should not really affect the drive part of the clutch, so I don´t know how this might be related to the slipping clutch, and I frankly don´t know what´s the matter with this clutch. For now it will stay in the “useless, but too expensive to scrap” part of the bin. For now, the STM 48T basket and plates, and Duc stock centre etc works just fine, but there are instances when I really miss the slipper function.

With the clutch working again, things worked pretty well except for the lambda plug falling out; I was sure I had lock-wired it, but apparently not …. But it was still in the belly pan, so quickly fixed.

Then, after the second stint of the 4th day I noticed this:

20170629_113653 by torbjörn bergström, on Flickr

Since the weather was none too good, and I was pretty done for, really, I decided to call it a day; don´t want to risk anyone being hit by silencer parts dropping off the bike.  
Back home, a pal welded the crack (I´ve never welded titanium), and some extra support to keep things on the bike if it did crack …

20170705_210718 by torbjörn bergström, on Flickr

Basically, the bike behaved well, but one major problem got very evident during the days at Gotland Ring: The abrupt throttle response in the transition from engine brake into the turns to drive out of the turns. Work kept me from doing anything about it and at the next two days at Anderstorp Raceway, the longest track in Sweden with mainly straights and wide, banked constant-radius turns it got even worse. The long turns, however, made it very obvious that depending on what RPM I cracked the throttle, response would be slightly more or slightly less bad, so doing something to the mapping would be next step.

Adding 5% fuel at  0% throttle and interpolating up to 6% throttle did a world of difference, and adding another % even better. It´s still not perfect, but perfectly tolerable.
Additionally, I swapped for a throttle I modified from “quick" To "progressive" years ago when I had the same problem on the M900. The mapping is the main cure, but I think the really slow opening from closed throttle helps a bit, too.

Schnellgas by torbjörn bergström, on Flickr

With these measures, the last two track days at the small Kinnekulle Ring were a relief, fo the first time everything seemed to work at least acceptably, and riding the bike made great fun.

With no other niggles to distract, and with speed and lean angles increasing, it became obvious that the suspension still is not quite OK; in turns there is still a faint but obvious chatter. It´s OK for this summer, but something I will have to look into over the winter. Sag values seem pretty OK, but the sensation when riding the bike is one of a stiff set-up, even with compression adjusters way out.
It may partly be the linear rear linkage giving another feel that I´m not used to, but  I´ll have to do something about the chatter.      

[koko64]

Bravo.
Dyno time now for some fine tuning and some suspension work.

[MonsterHPD]

Bravo.
Dyno time now for some fine tuning and some suspension work.

Hopefully, the tuned engine will be finished in time for the fine tuning .... the suspension seems to offer an opportunity for learning a thing or two :-) 

[Speeddog]

The broken fingers can roam around and possibly get into a position where they can jam against the pressure plate, holding it 'open' a bit.

[MonsterHPD]

Hello, everybody.

Quite a while since I updated here, reason beeing partly that not much has really happened, and since I´ve been busy with other stuff, like retiring from professional life.So I now have more time for doing whatever I like, but less money to do it with ....

I did some modifications to the front fork, allowing me to use the shorter (240 mm) springs for the last track day of the summer. However, I only ran a coupe of laps a couple of times each day, three laps or so into the stints the drizzle started, and the rest of the day it rained.

Anyway, I´ve just come back from Reactive Suspension in York, England after two days of suspension dyno seminar, and two days of further dyno testing at the suspension school (suspensionschool.com). Highly recommended for anyone with an interest in suspension.

Quite a few revelations over the days, and also actual test traces from the shocks of my M800, and of my track day bike.

This one shows the spread of the damping forces on compression (the positive traces):

Skärmklipp 2017-12-07 21.45.31 by torbjörn bergström, on Flickr

And this one shows the spread of the damping forces on rebound (the negative traces):

Skärmklipp 2017-12-07 22.27.16 by torbjörn bergström, on Flickr

The clicker positions can be seen to the left in the graphs.
The red / purple traces is the track bike, the blue ones is the M800.  

This really gives a completely new fact base to base re-shimming on. Had I had more easy access to the dyno, I could really design the damping I think I want, and see what difference the changes makes. But this is also far better than previous guesswork.

I and another seminar participant ran a lot of tests on the Penske shock. Both Gareth (Reactive Suspension´s owner) and my seminar mate (semi-professional, with his own dyno) rate the Penske highly, and I am inclined to agree: Good performance on the dyno, dead easy to work on, very good information material on their homepage, etc. The only negative is a slight tendency to develop shaft seal leaks, due to seal design. If I lived in the US, I think a Penske would be at least as natural a choice as an Öhlins is for me living in Sweden.

//Torbjörn.  

[Speeddog]

I'll be back later with at least a hundred questions.