I got the engine going on my soon to be street worthy F1, but at the 1-3K rpm my bike dies if I roll on the throttle hard. If I roll SLOWLY up to the 4 or 5K mark then I can hammer on the throttle with excellent response. Is this an air filter deal or jetting?

I have found I have a full Yosh exhaust and do not know if the carbs have been rejetted or not. I'm under the impression you should jet if you have the full Yosh system. Also I have a K&N filter (from what I read in earlier posts they aren't great) so I plan to switch it to the stock filter from my parts bike.

Any suggestions before I go insane and rip out my hair? (the wife say's I'll look like a q-tip if I do that)

Any advice is appreciated!

 

The K+N filter is better than stock. They need to be cleaned and oiled properly to get the benefit. Try running some seafoam through your bike. I usually add it to the fuel and then run the bike long enough that it had makes it into the carbs. Let the bike sit over night then ride it till its empty and repeat if necessary. Do that or pull the carbs and clean them.

 

Thanks Thrasher - I'll give it a shot. Since your Canadian as well - I'd imagine I can get Seafoam in Ontario (hopefully). The post is appreciated though.

 

Napa or Canadian tire carry it.

 

It could be a lot of things so you can start at the basics and just make sure the carbs are clean, you have no intake leaks, your idle speed is about 1200 rpm. If it runs fine everywhere else that doesn't preclude an issue with air leak somewhere.

If you have problems starting it (especially warm) without a choke than something is leaning it out.

Usually if you are getting a bad stumble under 4K and you changed exhaust and air cleaner your pilot jet is too small. Slow jet usually start off stock at a #35 and the main is a #105. try upping your slow jet up a couple of numbers.

KongBastard

 

Sounds like the carbs could be out of sync too. That or one of them has developed a dead spot. But I think a sync would do wonders.

 

Thanks guys ... guess I'll look into building a manometer next.