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Re: [turbobike] STILL floods when I turn fuel pump on.

Tim Drew (tim@timdrew.co.uk)
Tue, 26 Oct 1999 21:28 +0100 (BST)


If it's any help to you. I have the standard BST40SS carbs on my 1992 UK 
spec GSX-R11 and through experimentation I found the float needle valves 
would hold 5psi without the engine running, but with the engine running 
4psi was about maximum before the carbs would flood.

I now operate my bike with the fuel pressure set to 3psi over boost, and 
the float hights are set at 15mm which is about standard. These settings 
work just fine for me and I don't ever have any flooding problems.

Just a couple of things I'd recommend:

Return the fuel to the top of the tank and make sure there are no 
restrictions in this pipe. I use a 5/16" stand pipe in the tank with a 
wide radius 90deg bend.

When you adjust your regulator do it at your desired maximum boost      
pressure. (I found my regulator could be somewhat non liner at the low 
end!) What I did was plug the pipe to one pair of carbs and connect a 
pressure gauge in place of the second pair. I supplied the regulator with 
compressed air at 20psi and then adjusted the fuel pressure for 23psi. 
This will guarantee you always have 3psi over boost when it really 

Good luck


Tim Drew
Phone:  +44(0)7050 611846
FAX:    +44(0)8700 881993
ICQ:    52312721
E-mail: tim@timdrew.co.uk