so i'm running into a brick wall with a 94 f2. so whats happening is this:
i have rebuilt the carb (cleaned and jet kit) and even went back in 4 times making sure all was right.
i crank the bike and it will run at 1,000rpm not matter how much gas i give it. so while it's running at 1k i take the air box and filter off and she lights up and runs as if she had all the ***** in the world.

i know i know you say she's not getting enough air right? well i would go with that if i could prove that was the case but i cant because if i put the airbox back on while running (while running like a champ) she will continue to run well until turned off?

what do you guys think??

*mods i have this posted in the f2 section but no one is there. if a mod would be gracious enough to delete the f2 section post i would give many many thanks in return*

 

not now pops not now lol

 

Sorry, moved it to General Tech because it seems well, General Techie ...

Been a while since I jetted and played with carbs. I'm wondering from your description if the slide (piston) in one or more of the carbs is sticking when the bike is shut down. With the air box on there is not enough flow to lift it but once you get the flow and it gets past the stiction point it is fine.

How were the boots to the intake manifold? Sometimes a small leak there can play hell diagnosing other problems [:'(] Doesn't sound like a vacuum leak but never hurts to check out all those lines while your dinking around in there.

 

Have you done anything else to the bike? I ask because I replaced the rusted out 4-4 pipes on my 650 with a new 4-1, and couldn't get much over 55mph. Turns out that while the old pipes were restrictive, so was the airbox lid so it all balanced out. Once I put on less restrictive pipes I had to remove the airbox lid so the motor could breath.

So with that thought and Chain's post, how is your airfilter? Any restrictions in the ducting to the airbox?

 

lol *throws hands in the air and shakes head mumbling*

cb750
um just rejetted : adjustable slide needle, jets. the main thing though is i took two f2 carbs and made one out of it!

 

I like what chainstretcher said. If your slide isnt moving correctly and sticking, it will do exactly what your describing. Also, make sure the top diaphram is seated correctly. It can be tricky to get it just right, but I would pull the top caps off, remove the slides and make sure there isnt any dirt or grime inside of the diaphram. Also, there are a couple of ports under the diaphram, make sure they are clear and nothing is blocking them. then, be very careful to get the diaphrams seated correctly. Also a good time to make sure there arent any rips or tears in the diaphram.