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I have a 400 1WG that needs a new fuel pump. They're impossible to find over here. I bought an aftermarket pump, rated to 2-3 psi. It does'nt seem to supply enough fuel because the bike misfires above 10,000 rpm. Does anyone know what rating(psi) is needed to successfully run my 400? Any ideas on what wiil do the job? A 10,000 rpm limit is like owning a ferrari and being stuck in 1st gear. Cheers guys

Hey Jim, I just read through the 400 manual and it says nothing about fuel pump outlet psi. It just says, if it energizes and pumps fuel, then it works. If it doesn't, then it's broke.

I did find that the "pilot screw is 3½ turns out" and the float level is supposed to be set at "4.5~6.5mm below from the float chamber line"
(quoted directly from the manual)

edit: mis-spelling... I just quoted it the way I read it.

Typically most of the pulse type fuel pumps will pump 2-5 psi which is plenty for most carbs. The problem though is usually the pump has good pressure at low RPM but loses pressure at high RPM due to the pumps inability to flow enough fuel. That is why there are so many different types and sizes of fuel pumps. Fuel flow is actually more critical than pressure.
You may need a higher flow pump than what you currently have to supply your carbs.

Tim, my old pump only supplied enough gas to rev to 6000 rpm. The new pump allows the motor to rev to 10,000 rpm. However it misfires above this. I assume that there is insufficient pressure to supply gas above 10k.
I have had this problem previously and a new (used ) fuel pump solved the problem.

Hey Guys, I put a FZR250 pump in and alls good now. Cheers

frogfeaturesFZR wrote:Hey Guys, I put a FZR250 pump in and alls good now. Cheers

Theres a certain element of irony in that given that all of the FZR250 fuel pumps that i know of have died and had to have been replaced with other pumps! On my old FZR250 i replaced the fuel pump with one off a Kwaka ZZR600 and it worked perfectly.

I was thinking the same thing Koma