[Sam]

Sherco 2007 290 is fouling plug, runs boggish, carb/airbox always clean. Could this be related to a failing stator plate or CDI box. I have a 2006 Sherco that I can swap parts from, but just wonder if this could be electrical/heat related. Engine seal?

Thanks.
sam

[htrdoug]

Sam, on May 3 2010, 09:46 PM, said:

Sherco 2007 290 is fouling plug, runs boggish, carb/airbox always clean. Could this be related to a failing stator plate or CDI box. I have a 2006 Sherco that I can swap parts from, but just wonder if this could be electrical/heat related. Engine seal?

Thanks.
sam

Pressure test costs nothing, gives peace of mind...

[copemech]

Persuming your jetting is correct and has been so all along, mix is correct at 70-80:1 and all that, there is a possibility that the bike may indeed be sucking in a bit of lube from the gearbox side. Try measuring what comes out, VS what goes in! That might be a big clue!

450m ml would be your mark, drain it on a warmed motor so it should all come out easily.

There are some other tests we have done such as checking for unusual vacume or pressure on the case vent line, yet I admit it can be iffy. A full pressure test may reveal nothing, as too much pressure or vacume just seems to help the marginal seals seal better. It is on the subtile balance of the transitions that they will leak.

Do you have any floaty idle symptoms at times?

[B40RT]

Borrow / buy a coil and eliminate the cheap fix first.

[Sam]

Copemech,

I did a small test starting the Sherco and sprayed a little starter fluid behind flywheel and bike died and yes Idles very rough. When it heats up the exhaust smells unpleasant like gear oil being burnt. Could this be a double whamy, both seals going at once?
Someone told me that changing engine seals on Sherco's is a snap. You pluck them out with a dental instrument (be sure to sterlize in autoclave) then pop back in, is this procedure correct?

[Sam]

I'm sorry, I mean when changing engine seals on a Sherco no need to split cases.

[copemech]

Sam, on May 5 2010, 07:42 PM, said:

I'm sorry, I mean when changing engine seals on a Sherco no need to split cases.

Well yes, they may indeed both be leaking and deteorated as some the others have gone. Mainly attributed to the alcohol in the fuel best I can summize.

Your little test may have just confirmed that!

I replaced mine 2-3 months back, and they will pop out easily enough after removing the flywheel and stator plate on the left, then the clutch cover, clutch basket and primary drive gear on the right. Might require something a bit more sturdy than a dental pick to pry them out, as mine were stuck well and I had to use a small screwdriver, yet principal the same.

Current thoughts on the seals themselves. The current replacement parts through Sherco seem to be the standard black nitrile seals. If you want the upgraded and more expensive seals in Viton(resistant), then go to Splatshop UK, as he has sourced the better seals as well as an option. You will likely have them in a week.

Being a geek, I got the better ones, just simply in the hopes that myself or others may not need to contend with this issue for some time.



Tech notes on all this---------bs!

If you tear the clutch side cover gasket you will need a new one!

Those hose clamps suck on the wp hose, replace them with a screw clamp and can them! 8-22mm as I recall. Buy spares for the head!

Scribe both nuts and shafts on clutch hub, primary drive and flywheel so you can put them back up to proper torque (or slightly beyond marks) easily and quickly using a rattlegun rather than needing all them holders and such. Screw all that! I am lazy! I have tools to do it!

This whole thing really p****d me off, as while I had the clutch basket off, I started thinking about doing the Dan Williams clutch mod(Beta threads) on the Sherco!

Took me a while, yet I am happy with the outcome and glad I spent the afternoon fileing and polishing on plates and taking grooves out of the basket! Works good!

Once again, the geek took over, and I tried another experiment, and using the needle file put a small diagonal groove into every pad on every friction plate. Estimate 5-6 hours massaging this thing! Fingers numb!

My clutch works well, even with the two springs out! No slip or stick from cold using the synthetic Merc ATF! Your mileage may vary!

[Sam]

Copemech,

You have been very helpful, I hope other trials enthusiast find this thread informative.

Thanks Again.
Sam

[Neo]

copemech, on May 6 2010, 02:36 PM, said:

This whole thing really p****d me off, as while I had the clutch basket off, I started thinking about doing the Dan Williams clutch mod(Beta threads) on the Sherco!
Took me a while, yet I am happy with the outcome and glad I spent the afternoon fileing and polishing on plates and taking grooves out of the basket! Works good!
Once again, the geek took over, and I tried another experiment, and using the needle file put a small diagonal groove into every pad on every friction plate. Estimate 5-6 hours massaging this thing! Fingers numb!
My clutch works well, even with the two springs out! No slip or stick from cold using the synthetic Merc ATF! Your mileage may vary!

Hey Cope,

I don't think you mentioned you were doing this mod?.....Would have been a lot easier using Nulon oil instead .... easily said in hindsight I know

Best of balance.
Neo

[Sam]

Help!

Any suggestions on primary gear removal, the little bugger will not come off by lightly prying up and my gear puller is to big. I guess its hung up on the key.

Thank You.
sam

[Sam]

Should I use heat? My goal is to replace the seal.

[copemech]

When I did mine, I used a small slide hammer with a little "L" shaped adapter to slide under the gear edge and tap it right off. Does not take much to dislodge it, but I did not want to pry against the case edge either.

2K8 made a small puller out of an old pushbike pedal and a bolt, a thin metal strap would do. Must look for his old piccie!

[Sam]

Copemech,

Thanks again! Tomorrow will be a day of tinkering.

sam

[Sam]

Hurray It runs!

Harbor Freight saves the day. I bought the smallest gear puller they had with 2 arms then grind the claws to fit under the gear. I rassembled the machine and it ran worst then ever just like the choke was on. After a small inspection I discovered the float was stuck. Now she runs smooth and perfect.

So all you Sherco owners that are not mechanicaly inclined, If I can change engine seals anyone can!