hi everyone.

just got my self a nice little f2 a few weeks ago.
there was a lot of tatty bits and scuffs etc so ive removed all fairings and tank.
resprayed and re fitted.
went to start it but had left breathe/vacuum hose that comes from the top of engine on near side off the petlock. had a good few attempts at turning over thinking its just air or like in the fuel line. today, looked and realised my mistake
re connected hose and after a few turn overs got it to start. thing is, now it only idles while the choke is open. if i close it and dont keep reving it, it will stall. any ideas please..
thnks for any help offered.

Gavin

 

look for another vacuum leak. Intake boots are prone to not seal when they get old.
Turn up your idle.
Adjust/sync your carbs.

If all that fails, remove the carbs and clean/rebuild them.

 

What's an intake boot? Could a throttle adjustment sort it as if I turn off the child and put some slight revs on it stays idle. What about these cleaning additives? Any reccomendations, (sea foam maybe)

 

The intake boots are the 4 cylindrical rubber boots that each have one end clamped onto the carb, and the other clamped on the inlet tracts of the cylinder head - you can test for a vacuum leak there by getting the motor running from cold, and spraying a little carb cleaner around these boots - if the idle suddenly goes up, that means there's a bad seal around that area - the idle goes up because at the leak some of the carb cleaner is being sucked in and burnt in the engine.

It's not easy to diagnose an issue without working on the bike ourselves, or knowing any of it's detailed history, and if you haven't had it very long, you may not know for certain of any of its history either... that said, do you know if it has been sitting for a long period of time? Were the carbs modified in any way before, i.e., have jetting changes been made, or fuel screw settings changed? Going along with the last question, does the bike have an aftermarket hi-flow air filter, or an OEM-type paper filter? Stock exhaust or race headers? A real simple one: how old is the gas that's in the tank?

Like already mentioned, it might be as simple as your idle adjustment... all you have to do is turn the small black **** in the slot at the front of your left tail fairing clockwise to see if that makes the difference, but if you find you have to have the thing idling really high to stay running, then you need to look further.

Demon mentioned the possible need for adjustment to the carbs, or a cleaning, and like I already said, it's not easy for us to diagnose things without being there, so it's going to take some work from you to determine what exactly needs to be done... if the carb settings have never been altered from stock, the bike has stock exhaust/air filter, the idle adjustment setting is not the issue, there are no air leaks, and the bike has been sitting for a long time at some point, with the carbs never being cleaned, then my money would be on that they just need to be cleaned - properly and thoroughly.

You asked about additives: additives are more of a preventitive measure - Sea Foam is fantastic stuff, but let's say you've got filthy, gummed-up carbs, and your plan is to put Sea Foam, or a similar item, into the tank, and run it through to clean things up... this could work, but it also could take months for it to break down the carbon build-up and do so.

Start simple and work your way up - try adjusting the idle screw and check for an air leak, then go from there.

Oh, and vote for CBR of the Month - there are two F2s in the running this month : https://cbrforum.com/forum/cbr-month...thread-150840/

Good luck!

 

thanks for such a detailed reply. and i tried to vote but it wont let me take part.
im going to try and bottom the stalling issue this week so i will check what you said and get back to this thread ater in the week

thank for the replys guys.

Gavin

 

thanks for your help guys.
turned up the idle, all sorted.

 

This sounds about like my problem...
ive been through every cleaning issue but i cant get my bike to run off choke. it starts fine
on choke. I warm it up until the radiator hoses get hot (that is enough time right?), but if i try to rev it, it stalls. No matter what position I have to choke...
I have stripped the carbs of all rubber/plastic and sprayed/soaked with Berryman B-12 Chemtool and verified the jets are clean and clear with specialized tip cleaners. While cleaning the jet ports, I would spray in and look for the cleaner to exit another area of the carb. I can't get my head around this problem. She is driving me crazy. Please help