need yfz help asap

[EPDP99]

Got a buddy with a 04 yfz he bought with seized crank. Completely rebuilt motor(new, crank, piston, clutch, all bearings the works)with new stock parts. Only mods are intake, pipe, tokyo mods carb work and cam mod. Since built(recently) we have not been able to get it of idle smoothly. you can kinda rev through it fast but it still doesnt run well. He has tried a 42, 45, 48, 50 pilots different needles different positions on the needles, fuel screws with no change. took his wifes carb off her working 04yfz with no change. tried her rectifier, coil pack, cdi with no change. thought it might be stator acting goofy so he put her side cover on his with no change. put back to stock cam timing, re checked valves all with no change. fresh fuel, fresh spark plug checked the clutch lever switch..... where to go from here? I was thinking electrical like short or bad ground so he is in the process of runng temp ground from bat to frame because all they have stock are the bat to engine case. I also told him to check all plugs and make sure he is getting good connectiions but please help. Thanks in advance. We have been chasing this for about 3-4 weeks now and are stumped.

[EPDP99]

buddy took it to racer edge because he was tired of messing with it.... we will see what they say soon hopefully...

[EPDP99]

ended up being the throttle override system that had to be bypassed at carb and cdi...

[Jeremy]

Yamahas still have those?

[bajaman2000]

i was actually thinking about that. i had an issue with that on my yfz when i switched to the twist throttle

[EPDP99]

we unplugged it but you actually have to connect the wires in 2 different places I guess to bypass it...

[ElderGeek]

Yup! I did mine up in the harness when I was chasing a start problem. I did for get about the TOS until you posted it though.