Fuel selector switch

[dukesguy]

When I switch my fuel selector from "on" to "res", am I still using vacuum to keep the fuel flowing? I am going to rebuild the petcock vacuum parts, but just wondering if the vacuum is always there or not.

[shortleg]

 Yes you are,vacuum from #6 intake.
       Shortleg[Dave]

[John Schmidt]

Dave is correct. When switching to RES you're only changing the point at which the fuel enters the petcock pickup stem in the tank. Basically, on RES you're now pulling fuel from the bottom of the pickup instead of the top. You still need the vacuum to keep it open. As for rebuilding, remember....the petcock on these bikes is the weakest link in the fuel delivery chain. And that chain breaks down quite frequently. In the long run, you're better off going with an aftermarket unit as many of us have done. In my case and a host of other members, we have chosen to use the Pingel. In addition, I added an electric fuel valve so I don't even bother to shut the petcock off. Something for you to consider.

[Steve K (IA)]

But to be fair....there are those of us who have never had a petcock problem.  
OK, I'm knocking on wood.

[John Schmidt]

But to be fair....there are those of us who have never had a petcock problem.  
OK, I'm knocking on wood.

Careful Steve, I said the same thing in a post a few years back and.....uh oh, less than a week later it went south. 

[rmrc51]

Pingel!!! lol   

[98valk]

recomend installation of a snubber in the vacuum line. reduces extreme pulsations of the diaphragm which will increase its life.

search my threads on the subject. about $10 in parts.