[PhqOphRacing]

its my buddys bike, it barely takes any throttle, revs fine while sitting but under load it bucks and breaks up real bad, you can gently roll into it and it take it to about 8k then it starts breaking up.

it has a new tps sensor
its not throwing any codes
it has a new set of throttle bodies
ive swapped my gas tank (fuel pump) fuel line, ecm, and air box.

Nothing helps, im stumped and hes ready to ride, he bought the bike in mississippi and it starting running like this 2 days after he got it home

 

[Tro1086]

TPS adjusted proper? Secondary butterflies in TB's functioning properly? Secondary position sensor?

Sounds like a werid problem.

 

[audi1031]

Does this bike have a Power commanders or some type of fueling system. You should check the wires to the ECU and or swap ecu with another known working ecu as some people can edit the ECU's and you would never know if that one was

 

[2002GSXR1000]

Have you pulled some spark plugs to see what they look like?

 

[litshoot]

your screwed.

just joking. how many miles, what was done recently, has anything happened or changed. since its already bought i'd call the guyback and ask him what he knows about the problem. he could have sold a bike knowing that it needed something and didn't want to put the money. its shady but he may make it right buy at least letting you know whats wrong with it. also do no trust any of the work he may have done to it. recheck any tests he's done and look over all his work.

You've started off in a good direction. i'd check plugs, timing, valve clearance, carb sync.

Also does it have an aftermarket exhaust, if not could the exhaust valve be reversed. would cause high rpm problems. not likely but could be part of the problem.

 

[PhqOphRacing]

no power cammnder and ive switched my ecm in it, no changes

everything is adjusted right, ive had 2 other sets of throttle bodies on it and nothing helps.

the guy that owned said it ran perfect the whole time he owned it.

 

[cbreater]

Since you seem to be nice enough to tear your bike apart to loan parts about the only thing left are the coils and injectors or the harness for both. After that you are down to the motor itself being possibly a timing issue but not likely. It sounds like it's either dropping spark or fuel with my guess being fuel.
Is it the gear position sensor? If it's shit it could be throwing a bad timing map if it thinks your in N or something? :hmmm: