Mid-Range & Top end stall?

[kevslatvin]

Hey all, this is sort of a continuation of the "Whats it feel like topped out" thread. Did some riding today and the quad seems to have a stumble in the mid to top end range. It seems to be more RPM dependent than throttle position dependent. I can be in 5th or 6th at half throttle and it will start stumbling,almost like it is missing. I can give it more gas or nail it and it will clear up until my revs get up then it starts stumbling. It will stumble at the to of any gear by the way. You can check that thread to see what I have tried though it almost seems worse since I had the carb apart. I did strecth the accelerator pump spring while I had it apart. I'm begining to wonder if it is ignition related? Thanks.

P.S. I put fresh gas in it today so the gas should be good. Here is a link to the other thread.
http://yfm350.proboards31.com/index.cgi?board=quadrelated&action=display&thread=1151139842

 

[klutchbuster350]

sounds like jetting, If not, rev box.

 

[yamaha350r]

u kno the needle in the carb.... that was loose in mine and i had the same problem my guess is take it a part and look at the needle :/

 

[kevslatvin]

I moved the needle one notch toward lean and it didn't seem to change anything.I have since put it back stock. I initially thought I was lean and went up one on the main but it is back to the stock size as well. The main was before I discovered it would do it when it wasn't at full throttle. Pilot screw is set at two turns.

 

[kevslatvin]

Did some testing today with my timing light. Timing at idle is good.I rigged my light up so I could put the seat on an took it for a spin up the road. I can't seem to detect a change in the light when it starts cutting out, though I'm not sure I would at the RPM that it cuts out at. Sure the neighbors got a kick out of seeing me fly down the road with a timing gun pointed at my head. Anyway I'm back to supecting carb problems. I may try a new accelerator pump spring. I am considering just getting a rebuild kit and rebuilding the whole carb.

 

[kevslatvin]

I cleaned my air filter last week and re-oiled it, but never really got to ride. From what I could tell in the back yard it still did it. I had bought a rebuild kit for the carb so I rebuilt the carb yesterday. While I had it completly apart I sprayed it out real good with carb cleaner. After riding today I think it may be fixxed. Once it got warmed up I don't think I noticed it cutting out anymore. I could definately hold it in each gear longer. If the cows are out of the field maybe I can go to my brother-in-laws next weekend. I can open it up more there.Can't really get out of third in the woods by my house.