06 has me whipped for now!

[jeffboyd47m]

My friend has an 06 that runs really rough and ratty at 1/2 throttle. I spent the entire day with him on sunday in my shop trying to figure out the problem.

We started replacing electrical parts one at a time (I have enough spare parts to build a whole bike) and by the time we were through we had changed every electrical part including the wire harness. Nothing made a difference. We checked the valve clearence and timing. We took the carb off and went completely through it and found no problem. We changed and tried three seperate exhaust systems and made sure the filter was good. I'm at a complete loss as to what could be the problem.

He recently completely rebuilt the motor and installed new valves. He also runs a Athena big bore kit on it. The cams are stock and he has a ZipTy carb mod. When the motor was rebuilt it ran perfect, but has since developed this 1/2 throttle problem.

If anyone has any other ideas I'm ready to try anything at this point.

JB

[Ricco420]

jetting ?

[jeffboyd47m]

jetting ?

We played with the needle both up and down without any luck. The bike was running good before with the jetting that was in it and the weather has not changed to cold yet, so I would think it should be ok.

[Ricco420]

Fuel line? and filter?

[jeffboyd47m]

Fuel line? and filter?

I even pulled the petcock off and tore it apart, cleaned it and made sure of no problems. The fuel line is clear and we put a fresh filter on.

[Ricco420]

did you check the plug for any clues?

[grayracer513]

See what happens when the TPS is disconnected.

[jeffboyd47m]

See what happens when the TPS is disconnected.

I didn't think of that. In hindsight I should have swapped out the carb to see if that helped. I'll try that and let you know.

JB

[cowboyona426]

I would also take the time to check the metal plate in the carb slide. If anyone had the slide out (you mentioned the Zip Ty carb mod) its really easy to put that plate in upside down.

[Ga426owner]

See what happens when the TPS is disconnected.

my guess also is that the TPS Pre set setting has slipped....

[yz450fcranker]

my 09 dies the same rattle thing maybe a heavier flywheel makes it better but i dont think anything will make it better FOrever