Hi Guys its me again, I'm still helping my mate with his FZ1 last time it was a clutch prob which we sorted but this time he has a Missfire but its a strange one.
The symptom
When starting from cold it starts and run fine, this last a few minutes and then without being touched the revs drop and it starts to miss fire. Its all most like it runs Ok on choke but when that comes off it miss fires. How ever it will rev and seems Ok above 5k.
What we have tried so far
Checked Plugs, Coils with a multi meter, Replaced the fuel line, checked all vacuum hoses. There is no fault codes showing and the TPS is at 17 bottom and 94 top. It runs the same with the Tank up or down . He has a power commander fitted so we in plugged that and it made no difference. Checked the clutch and side stand switch's all ok.
Something happens when it get warmed up to a certain point, I'm thinking a sensor is failing or something but don't know.
Any one got any Ideas please as I'm stumped.