Hi all:

I have a 3 month old Sherco 2.9 2005. I have Keihin PWK 28 installed, 50 pilot, 115 main, neddle in the middle.

I have notice when I

Does it run OK with the Standard Carb?

If 'yes' put it back on til the other problem is sorted off the bike then try again.

I just have tunen it with Keihin, I dont like dellortos response, unfortunately my bike doesnt came with spare dellorto jets, and the ones included are 30 pilot and doesnt work, so I cant tune this carb as it should be...(ie. dell ortos carb)

Try removing the breather pipe from exhaust side of the bike, it tends to get nipped causing poor running especially when going up or down something steep.

This happened on mine a few times, I now drilled the breather on the other side out so I can use that instead.

I also notice your running a smaller main than mine with a larger pilot (125 main, 48 pilot) could be just the different climates

Hope that help's

Chris

Here's a few more ideas:

1. What does your spark plug look like after it quits? Is it wet or dry?

2. Check for flashing (little bits of plastic) hanging off inside of the airbox forward of the air filter at the seam between the airbox main body and airboot, they can find their way to the float bowl and cause some issues. Same goes for dirt that might have inadvertantly found its way there.

3. Verify again that the floats actuate properly. Is there some sort of obstruction that prevents their clean working when the carb is pitched forward? Probably not an issue with a brand new bike and carb, but worth checking anyway.

4. Leaner pilot could be helpful if it is rich, but since it seems to be affected while going downhill, it could be a mechanical issue of some sort.

5. Look at routing the right breather tube so that it doesn't get squeezed by the exhaust. While you are doing this, you may consider re-routing the taillight wires back over to the left of the frame main center spar away from the exhaust. Verify that the routing of the rear brake reservoir hose is clean, too.

Hope this helps!

Mike