Yamaha TRX850 Enthusiasts Forum

hi all, i was reading a link that dicky had put up, for witch i must say is great information, but i have question about the fuel tap and that is, if the tap is faulty and allowing fuel to the carbs and the float needle valve or o-ring is leaking then surely if you do a float level test with a piece of plastic pipe from the float bowl the level would keep rising or would it just keep putting fuel down the inlet manifold into the piston.
and does any one recommend a fuel that would resolve this problem.
and just one other question, i have a 97 trx850. i have done a compression test (please bare in mind the gauge i was using is a hand held with a rubber bung on the end). on cylinder 1 i got 120psi and on cylinder 2 130psi. is this adequate.

1: The fuel leakage through the vacuum diaphragm tap is slow. It takes a long time to leak enough fuel to cause trouble, but if all of the elements line up in exactly the wrong way, parking your bike in the shed can lead to disaster.
Replacing the shit tap with a proper one is the easiest and best solution.

2: Roughly equal pressures is good, but they should be up around 180psi. See if you can get a better gauge.

hi, thanks for the reply. why do you think i would be getting low pressure and what type of fuel tap would you recommend.

why do you think i would be getting low pressure

Because you're using a hand held push to seal tester, probably one handed coz you have to push the starter button (those testers are crap), and it probably can't handle more than 130psi (did I mention that those testers are crap?).
Try to borrow a proper screw in tester, or cough up a few bucks and take it to a mechanic who has one.
Sorry I don't have one to lend you, I don't even know what country you are in.

what type of fuel tap would you recommend.

Almost any normal on/off/res tap for a Yamaha will fit.
I think the one I bought many years ago was advertised for a DT175.
As long as the bolt spacing is the same it should work.
Sorry I can't remember the bolt spacing.

Hi marky19!

I could lend you my screw-in compression tester but most probably you (wherever you are) are not in the same country as I am (Germany).

In the German forum some guys use a Suzuki RGV 250 fuel tap.
I use a quick disconnecter in the fuel line as described in the old post you mentioned above.

BTW: Have you checked your oil for fuel before going on cranking the engine more and more?

Reminding greets from Munich!