Bike running like...

[kmx 193]

Alright gent's I'm posting this in the jetting section as I believe this is jetting related. Fully rebuilt engine just cant get the jets right. Could be the Colorado temp changes but this is getting old. I'm on the verge of tossing it and going fuel injection. Below is a short video of a few laps at a local area. As you might see the bike completely stalls out at one point. Any suggestions or hunches are very appricated thanks. Kevin

https://youtu.be/BL7D1myl2HI

[mlatour]

Bike : make, model, year ?

 

Engine : stock / modified ?

 

jetting specs :  stock settings / current setting ?

Edited October 8, 2015 by mlatour

[William1]

Jetting seems fine. If it were jetting, it would be consistent all the time.

 

You need to need the revs up a lot higher than you are At best, you are at 1/2 throttle.

 

You may have an electrical issue or possibly a clogged tank vent (Though I bet it is electrical).

[kmx 193]

Alright thanks for the info will. The bike is wide open at all times out of the corners and im feathering the clutch. I am running the o-ring chain on it because it my play bike and I don't really care to adjust every time I ride. Im thinking I may need a larger leak jet also considering on exit of corners the bike cuts out. For some reason the go pro doesn't pick the sound up well. If you listen its hitting the rev limiter all the time... another issue is at high rpms the bike cuts out on top. I agree with the electrical although the jetting is off. The needle is perfect. It pulls great 1/2 to 3/4. Issue is down low and up high. It's a 2007 rmz 250. that is ride number 6 on the new top end and complete valve train rebuild. Another hint that my help is the bike a the  start of the day run's better then later on after riding and its up to operating temp. At operating temp pulling the choke makes it run worse, engaging the hot start makes it run worse, To my knowledge this is good. Im thinking larger leak jet on top its slightly lean so slightly larger main jet. electrical wise I will have to start diagnosing. Obviously we have some issues if you think its 1/2 throttle... LOL

[William1]

Not jetting. It is electrical

Choke adds fuel, if it were lean, choke might help

Hot start adds air, if it were rich it might be better.

Leak jet only affects rapid throttle openings for about 0.7 seconds and really has little effect over 1/2 throttle

I never once heard it hit the limiter, at best, maybe running 8K. You may of twisted the grip all the way but the engine never rev's out.

Most electrical issues are worse at high rpm and get worse as the bike heats up. Eventually, the mis-firing occurs at lower and lower rpm and eventually, the bike will not run at all.

[kmx 193]

Alright so we narrowed it down more more than likely an electrical issue. What's your guess? Ill pop a new plug in it which it already has. I know nothing I grounding out.

[William1]

Most common is a bad coil or bad stator. Testing per the manual sometimes can identify the failing part but to do so, you have to ride the bike, get it nice and hot and then immediately perform the tests. Read the service manual for testing method specifics and tolerances.

[kmx 193]

Testing complete. Extremely low voltage output. Only visuals I can find are some spots looks like rubbing.

[kmx 193]

Counted 8 spots worn can this cause the problem ?