Ok, im at a loss we put my Busa (1397) on the dyno to map a new PC. First run was sad without the PC went to 1100 rpm, found one plug was dead. Changed new plugs and fired it back up. sounded better hitting on all four, Installed the PC and started to map the bike everything was going great untill we got to 7500 rpm then the bike cuts out like its hitting the rev limiter. everytime we make a run same thing 7500 or 8000 grand cuts back. we have changed everything we can think of, PC, ECU, tip over switch, unpluged the kill box for the air shifter, new battery and on charger to see if a voltage drop would cause it, nonthing. checked for loose grounds and bare wires nada. drained fuel and put racing fuel in it. lower rpms runs great sounds great pulls good to 7500 rpm then thats it. If anyone has had this happen please help us out. Thanks
Won't go past 7500 rpm HELP
- Thread starter Safaritow
- Start date
I was sort of thinking fuel delivery as well, but how is it cutting off? Does it just die, sputtering or is it like you click the kill switch and everything shuts down normally?
Yeah I saw that, but bouncing from the limiter and dying seem different to me... that is the part that I don't get.(Gunnybusa @ Dec. 18 2006,08:32)He says "cuts out like its hitting the rev limite" so it must be bouncing off of 7500.(MC MUSTANG @ Dec. 18 2006,06) I was sort of thinking fuel delivery as well, but how is it cutting off? Does it just die, sputtering or is it like you click the kill switch and everything shuts down normally?
I agree. If it just dies then it could be an ECU problem. My 02 was having a similar problem, it would wouldn’t go over 7500 it would just hang there, but the moment I shifted in to a higher gear ( causing the RPM's to drop ) it would take of again until it hit 7500 again. Turned out to be a bad fule pump.(MC MUSTANG @ Dec. 18 2006,06:42)Yeah I saw that, but bouncing from the limiter and dying seem different to me... that is the part that I don't get.(Gunnybusa @ Dec. 18 2006,08)
He says "cuts out like its hitting the rev limite" so it must be bouncing off of 7500.(MC MUSTANG @ Dec. 18 2006,06) I was sort of thinking fuel delivery as well, but how is it cutting off? Does it just die, sputtering or is it like you click the kill switch and everything shuts down normally?
) Check your fuel pressure 
+2(Professor @ Dec. 18 2006,10:40)+1(BA BUSA @ Dec. 18 2006,08) Check your fuel pressure
Did you happen to leave race gas in it for any extended time?
If you have race fuel, in the tank and the bike is not mapped for it, the bike will go over 8k!!!
That happen to my 1397!
Fuel filter/fuel delivery
BusaBusa00
Registered
Check your fuel line mine did that when it was kinked with the tank down. One way I checked that it was a bad line was I raised the tank all the way up and rev it, worked for me.
Ok, well its not a fuel ussue. The bike never ran out of fuel or leaned out at all on the dyno. What we did see was when it starts cutting out the tach goes crazy. and it will stay running below 7500 when you back off, just when you try to go past 7500 it will not let you. Im at a loss............If I find out whats doing this i will let you"all know......Thanks guys
HiYaBruceA
Registered
My '04 did that. It was the fuel pump, which I had replaced and now all is excellent. While the old fuel pump was giving me grief I noticed that when I unlocked the gas cap there was a pressure release. That had never happened before the original fuel pump went bad, nor does it happen now that the new fuel pump has been installed. This may be symptomatic of a bad pump. Does your 'busa do the same thing?
Find a friend with a busa and swap out CPUs.
Use a similar year, but doesn't have to be the same. I think 99-01 uses the same CPU and 02-06 uses the same. But I'm not 100% positive.
Use a similar year, but doesn't have to be the same. I think 99-01 uses the same CPU and 02-06 uses the same. But I'm not 100% positive.
Dumb question! Does the busa vent from the rim under the fuel cap? If so i know the Bandit would screw up from it being plugged with crap or water freezing when the vent hose was crimped or plugged! Also for the pressure being released are you sure or was it a vacuum? That would explain the new pump working when old one wouldn't. Or !!!
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