My bike is great out of the hole.. can run it up to 95 in third all day long ... But I can't hold top end .. I can barley keep her at 70 for more than a couple miles on the free way .... This bike sat for years .. I bought a motor for it about 5 years ago and this is the first season I have had it on the road ... I think eaither my carbs arnt jetted right for my micron pipe with no baffle or these carbs are still having issues ... Anyhow a friend has a real cheap set of f2 carbs but I havnt seen them yet ..has anyone done this .. are the f2 carbs heated (do they have coolant hoses and passages )

 

incorrect jetting shouldnt cause it to do that, i just put a full two bros system on mine and havent put a jet kit on it yet and i can still hold it at 80 no problem. not sure if f2 carbs would work, even if they would they werent designed specifically for the f3 so i wouldnt use them, just sounds like your carbs would need thoroughly cleaned and rebuilt. wouldnt hurt to put a new fuel filter on it too, and you say it sat for a while? is the tank clean?

 

Tank is spotless new filter and pump

 

give your carbs good cleaning then lol

 

i believe you will have to get rid of your ram air intake and the f2 are smaller bore than the f3 carbs. i just found out my 94 f2 somehow in the past ended up with f3 carbs and the guy somehow blocked off the throttle position sensor or hid it somehow because i dont see a wire for it. my intake doesnt line up on it. i can only bolt the lower part. the upper bolts are like 1/8th inch off and the intake needs to shift to the left like 1/8th inch also. im gonna buy a set of f2 carbs off ebay or something and put the f3 carbs on there or something

 

Did

 

Maybe we can trade

 

Sat for years-have your fuel tap checked for flow,check the carb intake boots (spray something w/ a high flashpoint on 'em while running).

I had a similar problem once,could pull well 1st to 3rd,4-6th would sputter above 6-7000.The higher the gear the worse it got.I did 2 things 2 FINALLY fix it,replaced the fuel tap,which I don't believe it was since I had a spare and that didn't work and then I rebuilt it,finally I retapped the plug threads,couple were worn (race bike,plugs came out a lot),that did it,but I put the new tap on at the same time but I swear it was losing compression or not firing right under load because the plugs were not fully seated.

 

this^^^^ my old f2 carbs are all jetted at .038 vs f3 at 0.35, 38, 38, 35.
i did get the f2 carbs on, but like iah said, airbox wont mate up, it did sound a LOT better. I tried swapping .035 for 038 on the f3 and threw the carbs all out of sync. worse than w the f3 carbs.