[Tex Law]

Mechanics,
I recently rebuilt and rejetted the carbs from a 1982 750 LTD. After installing them I cannot seem to get them to prime.The bike has the vac style petcock that I understand works in ON and RES. Does that mean the PRIME is a gravity fed situation and if so why am I not getting fuel to the bowls? After several attempts I opened the drains and the center two bowls had just a few drops of fuel while the outer bowls were still bone dry. Is there some kind of trick to load them up?
Thanks for any and all info.

Tex

 

[zoro]

Hey Tex, Welcome to the Forum! A vacuum operated petcock only uses vacuum to open the petcock when the engines running and the petcock position set at "ON" or "RES" (reserve). The petcock(if functioning correctly) will "close" and stop the flow of any fuel if no vacuum is supplied to the spring loaded diaframed valve inside the petcock. This was Kawasakis fix and safety component designed to keep the fuel in the tank and not on garage floors or in crank cases when float bowl needle valves failed or were maladjusted. The fuel should flow freely (engine running or not) when the petcock is in the "PRI" position. This is the position used to refill the carbs if removed for maintenance or if the bike was ran out of fuel. Always have a fire extinguisher handy when performing these tests! Is there no flow when the petcock is in the "PRI" position? You can remove the fuel line at the petcock, attach another length of fuel line long enough to drain into a gas can to test the petcock. There should "no flow" in the "ON" or "RES" positions and "flow" in the "PRI" position. Is the petcock working as described? You may have the carbs vented incorrectly,and/or the float bowl needle valve/float levels maladjusted.

 

[billybones]

I had to rebuild the petcock on my bike recently and put a new clear inline filter in as well. After getting everything back together, I put the selector to prime and got no flow (at the filter). I rechecked lines to be sure they were in the proper locations, everything looked good.

I decided to hit the starter and crank it a few times in Prime and got a big spash of fuel out of the vent hose. The fuel was rolling after that. Not sure what happened but everything was fine after that and no leaks.

Try pulling off the fuel line off the petcock to see if the fuel is coming out in Prime and work your way down from there. Only help I can offer.

 

[zoro]

I had to rebuild the petcock on my bike recently and put a new clear inline filter in as well. After getting everything back together, I put the selector to prime and got no flow (at the filter). I rechecked lines to be sure they were in the proper locations, everything looked good.

I decided to hit the starter and crank it a few times in Prime and got a big spash of fuel out of the vent hose. The fuel was rolling after that. Not sure what happened but everything was fine after that and no leaks.

Try pulling off the fuel line off the petcock to see if the fuel is coming out in Prime and work your way down from there. Only help I can offer.

Yes! +1, I too use clear lines and ALWAYS an inline fuel filter so as to "visually" varify flow. Heres another problem I encountered prior to switching to clear lines. My fuel line "Kinked" once it warmed up and stopped the flow!

 

[BrianTSmith99]

Maybe there was a bubble in the petcock stopping the flow?

My bike has no "Prime". Just Off/On/Res.

Brian