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Sherco Clutch Mods


copemech
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Ok, so I recently picked up a new(er) bike and I have to do my fettling with it. It is a "12 250 that has been ridden through our nationals this year and it is not too bad but needs a little attention.

I takes me many hours to go through things as I can, and this weekends project was the clutch, so in this series I will throw up a few sorry pics from my phone and possible suggestions fro those who like to play!

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You may first read through the Dan Williams clutch mods on the Beta to get a full idea of things and the general principals.

I appreciate Dan's efforts and these clutches being very similar, most all applies here. Having done my own experimentation, I take it a bit further to my own liking, therefore some of this applies to easy riders, and the more aggressive ones may not want to attempt some of it!

It basically requires a lot of time and a couple of tools! A fine ******* and a sharp tri- jewlers file.

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Polish and radious the tabs on the friction plates, sorry pic! Then as you will notice the steel plates ar stapmed, and have a sharp trailing edge on one side. I also knock off this sharp edge with the jewelers file to keep things running smooth.

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The steel plates in this bike had some corrosion and sign of possible water entry which actually left an imprint of every friction pad upon them, so I ran them through my glass bead blaster to clean them up. The glass does a finer finish than sand, and typically works well, but I think my blast media is a bit old, so I did hit them with a 500 grit on the drill for a final polish and a like new smooth feel to start with.

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After doing the tabs on the frictions, I use the triangular jewlers file to just put a few swipes on a diagonal cut into each little pad. This allows oil and air in and out to reduce surface tention that creates clutch sticking after sitting.

These plates did not seem to have a lot of excess glue as some I have seen in the past, so I did not mess with that!

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Edited by copemech
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Now on this bike, the clutch hub and basket was not grooved, so I did not get into that.

I will (on my bike) remove two oppsing springs upon reassenbly, and convert the bike to synthetic ATF for an ultralight clutch action.

This is not for all, and not for more aggressive riders. Although I may still yet try it again, I have found in the past that running the standard light gear oil produces unpredictable feel when running the light spring effect and may slip a bit when slamming it in higher gears, but with the thiner ATF things seem to work well with the ultralight(1/3) less tension.

Anyway, I can say I have never had the clutch stick after sitting in the last couple years with my old (07) bike. Although I am always cautious!

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I'm going to have to remember what gear oil I put in last time,But my 2011 was sticking BADLY when cold and I was planning to do the Beta fix as it worked wonders on my Fantic,but my Sherco seems to have corrected itself and now works wonderfully. Everything I put ATF in makes the clutch work good but shifting gets clunky when hot,makes me worry about my transmission.

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I'm going to have to remember what gear oil I put in last time,But my 2011 was sticking BADLY when cold and I was planning to do the Beta fix as it worked wonders on my Fantic,but my Sherco seems to have corrected itself and now works wonderfully. Everything I put ATF in makes the clutch work good but shifting gets clunky when hot,makes me worry about my transmission.

Hey Doug, here is the lazy-man's "fix" for sticking clutch plates on startup - put the bike in 5th gear prior to kick starting her... This un-sticks the plates the vast majority of the time, with no need to go through the alteration process, or changing to ATF, etc. And you then get the stock clutch feel and shifting.

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Mark, Mr. pedantic here, I would have removed that surface glue between the friction blocks since you've gone to the trouble of stripping her down that far...but that's just me.

The layer on these is very thin, not splattered all over like some, so not neccessary to me. Add, I am not that anal!

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thanks for posting copey but i dont have an issue with the std clutch ? what problem does this solve ?

Boredom!

Actually, the stock Sherco clutch is very good you know. Some find the bite point a bit abrupt(on/off). I do think this helps smooth the action just a bit, but the real factor here is that after using the (less two springs) light action now for couple years, I have become spoiled with it and my old arthritic finger appreciates it as well.

The plates sticking is just a nuisance issue for me, but in fact it can be a bit unsafe for those unaware. I still never totally trust them.

To me, this is like putting the strawberry topping on the cheesecake, but to be honest, it is a pain in the ass to do.

I do agree with Doug in the sense they do seem to have just a bit more gear rattle on the light oil, but I have no problems with its lubricating ability, we run 4WD transfer cases and such on that stuff, and that is not even the high spec full synthetic. It is designed to apply clutches smoothly and positively! And provide gear lubrication as well.

Nothing here states one HAS to go light oil or soft on the springs, that is my choice, but with the other things, one may still find a better action.

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Hey Doug, here is the lazy-man's "fix" for sticking clutch plates on startup - put the bike in 5th gear prior to kick starting her... This un-sticks the plates the vast majority of the time, with no need to go through the alteration process, or changing to ATF, etc. And you then get the stock clutch feel and shifting.

Oh that's what I'd been doing,As a matter of fact I always put any two-stroke in gear and rock it back and forth before starting it to prime the engine,I was a Maico rider BITD so if I didn't want kick-back I had a set procedure to follow.

I'm running Maxima gear oil,oddly it's the same as JimmyZ was running but after 1 change to PJ1 Clutch tuner which did nothing to help the clutch disengagement but made shifting clunky like ATF a return to Maxima gave me a clutch that is free upon cold startup even after sitting a week.

The next temptation may be to run the next step higher viscosity oil in the trans,which usually causes a firmer clutch pull,Just too see how it makes the clutch feel and how it shifts.I don't know which brand to try,so I will likely put that off for awhile,good experiment for hot summer I'd say.

Next time I feel the need to try ATF I will use Valvoline Maxlife,It meets an impressive range of automotive manufacturers specs.

P.S. I definitely don't care for Gas Gas clutch action after owning a Sherco,yet my vintage Fantic feels ok,even with it's firmer pull.

Edited by htrdoug
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