High Rpms On Start Up On 2001 Busa After Major Tuneup




TRALL

Registered
Hello there fellow riders. On my 5th Busa. Just got a 2001 from a local dealer. No history but one owner and near perfect condition with 23,000 miles. Bought it to setup as sport touring as with past ones. Had it for one month and several great riding days in IL. early this year. Bike was riding perfect but I did a major tune-up for prevention and to update mechanicals from things that fail from age and time. Also doing first major sport touring mod with LSL sport handlebar conversion.

So I just did the following work in the past two days- Installed LSL handlebar set-up, changed NGK CR8E spark plugs with .07-08 gap , new air filter, new stainless front brake lever, bleed and flushed front brake, clutch fluid, and rear brake, lubed throttle cables, changed radiator fluid, new thermostat, radiator cap, thermoswitch, water temp sensor, and new Yuasa Battery.

Afterwards - Went to start bike to bleed radiator system and bike won't crank or do anything when pressing starter. Yes bike was in neutral and kill switch in on position from first try. Checked all connections and tip sensor since I had gas tank off bike and everything looks connected. Checked hand clutch and messed with manual choke control housing near hand clutch and tried to start bike and for whatever reason it would crank and started but was at high-full throttle RPM so I instantly hit kill switch within 2 seconds.

I took apart throttle control housing and checked cables and checked throttle housing on engine and all looks normal. No binding of throttle cable. Throttle grip springs back after releasing.

Tried to start bike again, same thing starts at crazy high rpm, I instantly turning off in two seconds.

Check air cleaner and all vacuum hoses and air cleaner housing connected and normal.

Tried to start bike again and same thing- start at crazy high rpm and I instantly turn off.

I am not sure what else, I can do and hoping someone on the Org might know before I take it to dealer that has a Master tech with 20 years on the job.............
 

TRALL

Registered
So I just did the following work in the past two days- Installed LSL handlebar set-up, changed NGK CR8E spark plugs with .07-08 gap , new air filter, new stainless front brake lever, bleed and flushed front brake, clutch fluid, and rear brake, lubed throttle cables, changed radiator fluid, new thermostat, radiator cap, thermoswitch, water temp sensor, and new Yuasa battery
Correction -installed new front brake line not lever.

Also when I start bike each time for two seconds I have the manual choke off and confirmed this by watching the position at other end of choke cable on engine.

Iam at a loss on what else to check. Still thinking it would be throttle cables but there lubed and not binding and throttle grip resets in the forward position and springs back if use throttle with engine off.
 

David Offor

Registered
Try disconnecting the throttle cables from the linkage and run it with the air box off, to see what the butterfly's/flaps are doing, for it to rev up like you've described, the flaps must be visably opening.
Sounds like a mechanical problem.
 

TRALL

Registered
David,
With your direction it was something simple. I did check the throttle body linkage and could see the original stopping point had a 1/4 gap with the cables and hand throttle in the idling position all the way forward. So that was the issue. I have to readjust the cables so there not 1/4 advanced causing the high RPM issue from startup. Since it will be years before, I'll need to get in this area again, I went ahead and removed the air housing to double check and the butterfly flaps were closed and opened with the turn of the hand throttle like they should. I used some throttle body cleaner and spayed it on a clean wash cloth and cleaned them up since I could see a slight layer of grime from time and use. Put the air housing back on and removed the cables from the linkage and the linkage rests on the stopping point and my bike started purring again.
So just have to check my manual and figure out the correct adjustment and then bleed the radiator and it will be all done. Thanks again......
 

David Offor

Registered
1/4" gap!!! Yehr, that would do it lol.
I think I read in the Haynes manual, that there should be about 3mm of slack in the cables, at the linkage but it's a personal preference thing, I think, unless, you want to be at warp, as soon as you fire it up of course, in which case, leave it as it is :thumbsup:
 



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