Hallo all.

Hope you have some advice for me.

I have a problem with my Fireblade 929. I have had the bike now for 3 weeks and this morning the bike started to do something that is not right:

This only happens some times. When I accelerate the bike then sometimes the engine makes a funny sound like it is misfiring or something (bogging down)and has no power but when the revs go above 7000 then suddenly the power kicks in and the bike pulls strongly. I did check the exhaust and airbox flap/valve thing as I heard that this is activated at about 7000 rpm and it seems that they are working properly ( The exhaust valve goes 90 deg clockwise at about 3000 rpm and then 180 anti clockwise above 7000 rpm as per the Hayens manual).

Any help would be appreciated.

 

The manual should have an outline for troublshooting the engine becasue of poor performance at idle and low speed.

1. Check timing
2. check starter valve synchronization
3. Check all fuel flow
4. Inspect injectors
5. check for intake leaks
6. do a spark test

Go through these steps using your manual and let us know where you're at from there. I'm going to guess that timing and fuel flow are going to be your culprits, just as with my bike.

Good luck!

 

mine did the same thing, was like it misfires between 5k and 7k rpms, i changed out the throttle boddies and it fixed it. injectors and all. i have a good set if you wanna try it. i tried changing plugs and filter and cam chain tensioner, but it didnt work till i swapped out the fuel injection. someone told me i had to reajust something, but it involved drilling out metal in the throttle boddy area, so i just appted to swap out for newer ones.

 

you run race fuel? Sometimes fuel type can damage plastic, like the plastic in fuel filter screens. but that usually will give you a symptom of good power everywhere until you are at max load and high speed. I would replace plugs, check the air flap in air box to make sure it is align right. I would check fuel pressure while this is happening, but you may not have the means of doing that. But about the other guy saying new throttlebodies and injectors....that is a pricey attempt to try. But that may work. But the test above will rule out fuel pump, possible ignition issues, but other than that i don't know where to go. Hope it helps