My buddy needs help 02 gsxr 750

[black diamond busa]

"02 gsxr750. Replaced upper tps, plugs, k&n air filter, checked and cleaned injectors. It backfires and spit fire when letting off gas after a steady throttle pull and when I squeeze the clutch it backfires. When i let off throttle its slams me back cuz the bike decelerates faster than.should. also it stalls if I try to stop to fast. I can't hold a constant speed because it chugs and lurches. Now when i replaced the sensor and adjusted it right almost all of the jerky ness went away and i can hold it at a constant speed almost all the time. Except for so often it will jerk. But it still stalls and backfires." That all the info I that he gave me. The gsxr forum is telling him power commander but he does have that money right now. It also has a Two Brothers slip on can. Thanks for any help guys

 

[StrtRac3r]

No fi light? And with those mods it should be more of a lean condition. I think if there are no check lights on and all the electrical parts are good I'd check the throttle bodies, and vacuum lines. Is the idle irregular? Also if it's riding real rough check the chain tension and cush rubbers.

That's all the ideas I have, anyone correct me if I'm wrong.

 

[Fastfrog007]

Unplug the power commander and go for a short spin, least rule it out as the problem.

Smellphone via Forum Runner

 

[black diamond busa]

He doesn't have a PC yet. Also he said he is getting about a 100 miles to his tank so wouldn't that be a rich issue?

 

[black diamond busa]

No fi light? And with those mods it should be more of a lean condition. I think if there are no check lights on and all the electrical parts are good I'd check the throttle bodies, and vacuum lines. Is the idle irregular? Also if it's riding real rough check the chain tension and cush rubbers.

That's all the ideas I have, anyone correct me if I'm wrong.

Next time I'm over there I will check all his vacuum lines and no FI light

 

[newb]

try running a good fuel system cleaner through it. dirty valves may not be seating cleanly. too much cheap gas may have gunked up the motor. also, does he run it pretty hard every so often? i knew a guy who was scared of his CBR 1000. he never got the RPMs above about 5k. Pulled the airbox and looked at the back of his valves through the throttle bodies and they looked like the bike had 1000 miles after about 1500 miles. that thing smoked like the rings were shot.

 

[black diamond busa]

So I looked at it and he had the vacuum line to the MAP sensor unplugged!!!
It runs smooth and no back firing or stalling. He said its got alot more power now lol found the problem 2 minutes after he had the tank pulled.

 

[newb]

Funny how that works. Glad you got it figured out and it was nothing major. Amazing how the simple things cause the biggest problems.

 

[karnage]

Yeah an unplugged MAP sensor causes a lot of issues with running.

 

[black diamond busa]

Yeah I I'm really glad it was simple. He was trying to fix it for the last 2 weeks. Busa to the rescue