Z fuel pump....Diaphrams good. Hoses good, what else??

[Yamahauler]

When you kick the bike over with the gas line off, only a few dribbles come out of the petcock.

I opened up my Z fuel pump expecting the diaphrams to be cracked, they looked fine. Seals were all good. There was some dirt in it, and there was quite a bit of stuff in the filter. I cleaned that all up.

I put it all back together using the same parts. Then I checked the vacuum line, took it off, blew in it to check for leaks, The hose is fine.

I cleaned out all the dirt from the inside of the pump, could this of been the problem? What else do I check before I put the pump back on?

[Unclediezel]

Take the gas cap off-----

[Yamahauler]

I tried that already;)

The top end has 190lbs of compression

I was reading old threads and one said you can have a vacuum leak in your bottom end, and still have good compression up top.

How would you determine if this was the problem

[Yamahauler]

I just went out and tried the tri-moto 175 fuel pump I have and it shot out fuel.

Can the Diaphrams appear to be good, but the fuel pump still be weak.

I talked to yamaha, they said you cant order the fuel pump rebuild kits for the tri-z anymore, where else can you get one?

[Kintore]

I got one from yamaha no problems a few months ago. Thats odd!

[TimSr]

Im going to asssume you have pulled the hose off where it goes into the fuel pump and verified gas is flowing that far. In the fuel pump, check the little rubber one way valves. If a small piece of debris is holding one open, youll get very little fuel.

[Yamahauler]

Yea, theres great fuel flow to the pump. I had the fuel lines taped up so the gas didnt pour out of them because I had a half tank. I went to work, got back home and the lines got loose and all the gas leaked onto the floor, pissed me off :evil: