Reply To: Miss and backfire under 5k only after engine warms up – 2009 GT650R
Sprag Clutch = Age , wear and tear , or premature damage (if the last owner neglected the bike and was busy trying to start it 1000x a day, it could wear it down a lot faster) but you won’t know until you remove it off the flywheel.
Idling = Does it ever cut out when idling hot even at 1,100 rpm ? If not, could you recheck your throttle body TPS and possibly the lambda sensor using the service manual to match up any values within OEM spec ?
If we were to assume the basics ==> A carb bike that’s struggling to hold 1500 rpm would indicate blocked pilots or poor floats (EFI= Fuel pump or injectors)
or else
the idle adjuster knob needs increasing to 1500 rpm when hot (EFI= your ISCV unit should maintain idle when ride is not touching throttle tube but alas , EFI also means airbox sensors & throttle body sensors need checking too)
or else
We must check the entire ignition system both EFi & Carby => coils, caps, stator and CDI (EFi= ECU)
I believe you solved the ignition issues?
or else
If the rpm needle is going up and down in a sweeping fashion (1200 – 1800rpm), this carb bike would suggest its hunting for fuel or plugs are wanning => Replace plugs or check float height (For EFi = Fuel pump and injectors and/or ISCV unit + TPS)
At this point, you have done more progress with it , so you should be happy it’s not dying as much ? We getting there. Welcome to EFi world! Carby sounds easier doesn’t it ? but EFI is more “snappy & responsive” on the throttle!