My '97 220 sometimes dies while clutching going down steep hills. It idles fine and runs great under all other conditions. It may be getting worse because it died a couple times yesterday while crossing logs. It seems to only do it when you clutch while moving. Is this merely a jetting problem?
If you are idling in gear the clutch drag might cause it to stall. Try just standing still and put in gear with out reving. It will probably stall. That may be the reason but I don't know what to tell you about fixing it except up the idle or blip the gas a bit. Thats my opinion but I could be wrong.
FWW, even on a 220? I thought that was the point of a 220. I'll try the air screw, it seems to me like it might be "flooding" a bit causing it to die. With the cooler air now, it may be time to reset the clip. I hate to change much because it's running so well the rest of the time.
FWW is flywheel weight. It's a plate that bolts onto the flywheel. The added weight makes the engine harder to stall, and smoothes out the powerband making the bike more tractable. The trade off, a slower revving engine, which is worth the benifits.
Oooohhhh! OK!! My '03 220 does seem to have a fairly heavy weight already compared to my '01 kx500. The 220 runs much smoother and revs up and down much slower. Thanks for the terminology lesson!!
Turning the airscrew out helped this past weekend. I rode with 5 other people, 4 four-strokes and 1 two-stroke. Their four-strokes died more often than the twos! They were running MX bikes though and we were on "trail" bikes. I think the problem was a mixture issue and not a flywheel issue. As the weather cools more, I'll probably have to richen up my main jet to avoid any lean running.