fuel petcock

this fuel petcock is new to me. when do you guys use it? res/prime/on/off? stupid question? most likely. :S

ON & RES --- fuel only flows when the engine is running --- engine vacuum actuates a spring loaded diaphragm --- when the engine is stopped, the spring returns the diaphragm to the closed/off position.

PRI --- bypasses the diaphragm assy -->> fuel flows -->> engine stopped or engine running.
Use PRI to prime the carburetors. If left in PRI while the bike is parked, fuel may leak out the carb overflow tubing.

Use ON during normal riding. Switch to RES when the fuel gets low & the bike starts sputtering from lack of fuel.

RES = reserve --- uses up the remaining 1/2 gallon or so of fuel in the tank. You can go 10-20 miles on RES, so refuel asap.

gixxerkidd03 wrote: this fuel petcock is new to me. when do you guys use it? res/prime/on/off? stupid question? most likely. :S

PLEASE add your bike's year and model to your signature line.
Ed

thank Ed. udated profile. good to know the estimated milage on reserve with no fuel guage.
Eric

The reserve is probably 0.5 gals --- see the owner's manual.
You can figure out the RES range by riding the bike until it sputters from low fuel; switch to RES, noting the mileage; then ride the bike until it's out of fuel & note the number of miles ridden (bring along a gallon of fuel of course).

I think the 81 750E has a low fuel warning light. On my 81 650-CSR I can go ~10 miles after it starts to glow before switching to RES, then ~20 miles until empty.

I'm bring this back alive for a moment. So when I put it on PRIM I have a fuel leak but I'm not sure from where yet petcock was rebuilt and I have a vacuum line running only to cyl.#2? Is that right? The rest are capped off?
The carbs where just rebuilt and jetted by a buddy of mine so I wanna double check the float height.

I have done some searches and seems I maybe beating a dead horse here, sorry.

Eric

martin_csr wrote: ON & RES --- fuel only flows when the engine is running --- engine vacuum actuates a spring loaded diaphragm --- when the engine is stopped, the spring returns the diaphragm to the closed/off position.

PRI --- bypasses the diaphragm assy -->> fuel flows -->> engine stopped or engine running.
Use PRI to prime the carburetors. If left in PRI while the bike is parked, fuel may leak out the carb overflow tubing.

Use ON during normal riding. Switch to RES when the fuel gets low & the bike starts sputtering from lack of fuel.

RES = reserve --- uses up the remaining 1/2 gallon or so of fuel in the tank. You can go 10-20 miles on RES, so refuel asap.

Love your responses...so easy to relate, and to the heart of the issue. Keep it up!