I was out riding my 04 Sherco 2.9 yesterday and all was well it had been running like a top all evening.

I was done riding and was headed back home in fourth gear and all of the sudden the engine just cut off completely.

It will fire but only briefly and will not run for more than a second or so even then only very occasionally.

I changed the plug, cleaned the carb and it's acting the same way.

It's not a fuel issue as it was not changed and will act the same if I kick it and spray new fuel through the carb with the airbox removed.

Although I've not tested with a compression tester it kicks hard and sure seems to have plenty of compression also this problem happened almost instantly

and it had ran perfectly up until it shut off. I did remove the exhaust and had a look at the piston and ring and they look as new.

Reeds looked fine as well.

Anyway, The spark looks to me to be very weak and I suspect the problem is with ignition.

I've read Sherco's can have ignition issues but it looks like I need a special tool (that I don't have) to have a look under the flywheel.

I'm thinking about just taking it somewhere local because I want it fixed ASAP and I am busy running my business all week.

I am a little worried they won't know where to get parts or whatever else...

Is it an issue taking these bikes to a shop that works on the standard Japanese motocross bikes and the like?

Yes it is! They know nothing about it!

Spark allways looks weak, because it is. Eithere there or not for the most part.

Quick die out does suggest ignition related issue. Try unplugging kill button, ck elect connections to cdi and the ground wire to frame.

A faulty stator is allways a possibility, and even the cdi/coil unit, but without good parts to exchange and try makes it tough.

Ck that stuff and do tell.

A gent at one of our trials had his Sherco running great the day before and he washed it. Then the day of event it would not run. We unbolted the bracket that holds the "magic box" up by the steering head and cleaned the part of the bracket that contacted the frame and the frame where the two met and it ran fine after that.

A Sherco Flywheel puller can be purchased from Ryan Young Products. https://secure.rypusa.com/prodpage.cfm?cat_selected=175&product_selected=89&startrow=1

If you have sheared a flywheel key.

Flywheel key in packs of 25 (I believe this is right one, it's the link I saved from when I had a Sherco)

http://www.mcmaster.com/#98490a160/=rxkl4d

Thanks guys for the tips.

Guess I'll hold off on calling the shop, having nightmares of them keeping it for a month and accomplishing nothing.

I did check the kill switch right away will have a look at the other stuff as well.

-Mark

Flywheel key sheared?

Sorry just noticed it's been mentioned above!

Edited May 12, 201412 yr by jfc

I've checked everything (except flywheel key) and no dice same behavior.

Cleaned the ground to the lleonelli CDI unit, unplugged the kill switch.

I have a flywheel puller on the way from RYP then I will be able to test the stator

and trigger AFAIK.

Can't see if the key is busted until flywheel is off.

This sucks I feel like a kid who's had all his toys taken away

Where do you live?

I've checked everything (except flywheel key) and no dice same behavior.

Cleaned the ground to the lleonelli CDI unit, unplugged the kill switch.

I have a flywheel puller on the way from RYP then I will be able to test the stator

and trigger AFAIK.

Can't see if the key is busted until flywheel is off.

This sucks I feel like a kid who's had all his toys taken away

You don't need to remove the flywheel to test the stator & trigger, unplug at the cdi/coil pack & measure there.

Values have been posted numerous times before but haven't ended up being pinned to the top of the page, do a search should find them otherwise I may still have them or could measure my new spare stator for you

I am in Michigan USA.

Thanks Tony, I was wondering if I could measure at the other end.

I've seen those values while looking around I will have a look.

-Mark

http://uk-motoplat.com/testing.html may be of help just for info, not expecting you to send stator to uk.

Edited May 12, 201412 yr by dadof2

Values courtesy of Splat Shop but will post here if perhaps someone in the future stumbles onto this thread with a similar issue;

Testing and checking your Sherco stator plates, only applicable to the Leonelli stators from 2002 to 2007.

The trigger, using the diode check mode on a multi meter, you should get reading something like this, don't worry about exact numbers if it is somewhere in the same region.

Using the red lead to the plug terminals and black to earth.
Blue no reading (sometimes shown as 1 or error)
Brown 1000 to 1600
Black 1050 to 1650

Using the leads the other way around i.e. black lead to the coloured wires, red to earth.
Blue 600 to 730
Brown 650 to 770
Black 650 to 770

Also test the resistance's of the other coil wires, leads either way around.
White to red 95 ohms
Red to green 550 ohms
Green to white 640 ohms

http://uk-motoplat.com/testing.html may be of help just for info, not expecting you to send stator to uk.

Yep those are the same... was posting same time... I will send it to the moon if I have to, I just want to ride my bike again....

OK I have tested the stator wires and the values ARE out of recommended.

Recommended values in black, mine are in red;

Blue no reading (sometimes shown as 1 or error) 1

Brown 1000 to 1600 1946

Black 1050 to 1650 1895

Using the leads the other way around i.e. black lead to the coloured wires, red to earth.

Blue 600 to 730 678

Brown 650 to 770 727

Black 650 to 770 728

Also test the resistance's of the other coil wires, leads either way around.

White to red 95 ohms 85

Red to green 550 ohms 542

Green to white 640 ohms 619

I'm not sure how to interpret these results is this conclusive that the stator is bad?

Is so I'd probably want one with the upgraded hall switch, what is the fastest option

for replacing it? I am in USA.

Hrmmmm no motoplat expert but if you are measuring to ground or engine case you seem to have high resistance. You have a good group in your area. I PM'ed you my number. Lets try and get you some local help to double check.

--Biff

I grounded right to the ground bolt the other ignition items ground to. I cleaned it it's a solid ground.

I'll give you a call in a sec thanks!

-Mark