Bonneville America Forums Forums Technical Forums General Tech Fuel shut off curiosity

So, I've always heard that the fuel shut off switch should always be turned to the off position if the bike is not running. Ordinarily in the summer, I have to admit that I don't. I ride the thing every day. This time of year however, I ride only when the weather is permitting (with five to seven inches of snow supposed to fall tonight, guess that won't be any time in the next couple of days). Anyway, if I'm not going to be riding it for a while I try to make sure that its turned off, but I started to get curious about what the risks are of leaving it on. My dealer says "NEVER" under any circumstances should it be left on. That somehow the bike will explode if you do (okay, she didn't say that exactly, but close). So what are the risk? Is it okay to leave it on if I'm riding daily, like I do in the summer? Just curious.

Your float(s) may stick and then allow fuel to free flow.

Safety first! Like seat belts, turning it on and off can turn into a mindless habit. I leave mine on while out riding, but always turn off when I get home.

I never turn my fuel off and have never had a problem.

It's a holdover from the days of pure gravity-feed petcocks.

Ours is controlled by a vacuum diaphragm.

I have always turned the valve off every time I turn the ignition off. That way you will never get a leak on the floor and all over the engine. I actually turn the valve off let the engine run for a couple seconds then turn the key off. I do the reverse to start. One time Tom came over for me to fix his bike we went for a ride after I fixed it. I turned the gas off every time we stopped. He took off every time without turning it on. We got a laugh out of it. What it boils down to is that it isn't mandatory but it is a good safety precaution to get in the habbit of doing. In addition to a mess if a float did leak it could also wash rings clean and contaminate your oil in a cyl with the intake valve open.

Got it. See, I was curious what the potential bad side effects were. I figured it might just be something that used to be a bigger deal than it is with modern engines. When I had my Honda I never bothered turning it off and never had a problem, but as these are carbeurated I didn't know if that made a difference or not. My wife always turns hers off and occaisionally forgets to turn it back on. Thats funny, but I've noticed that it lacks the same humor when I do it. At least I think it does . Where I used to really embarass myself was that I would leave the key in the ignition with the lights on and kill the battery. My older bikes used to have keys that were up on the front, but the Honda had a key that was down underneath my leg on the side. Out of sight, out of mind. Took about six or seven times to really get in the habit of getting that key out. The Triumph is even worse because now the key's behind me, but I've been lucky so far. My memory sucks.

I have forgotten to turn it back on,everyone does once in awhile that turn it off. My friends and I have those helmet stickers that say "turn the gas on dummy" and we trade them back and forth when we forget. One guy is really bad and has it on his gas cap!

I shut mine off all the time and Ive never forgotten to turn it on..........ok , maybe once.........or was it twice........

Because I always run until out of gas and switch to reserve while riding, the few times I've forgotten to turn on the fuel resulted in the same automatic reaction.

If the floats get stuck in the feed position, a significant fuel spill could occur.
Chances are it won't happen, but it sure wouldn't hurt to shut off the fuel.

See also: Gas bottles on gas grills. I leave mine on.
A bad habit to be sure, but I am a card carrying member of the RWSLA:
The Running With Scissors League of America.

OK, imagine your bike parked in a nice warm spot. Carbs warm up, hte gas in the bowls expands. Some goes down the overflow hoses, some squirts out the main jet. The gas that squirted out into the carbs evaporates, cooling them down so the gas in the bowls contracts. The floats open and the bowls fill up again. Then they warm up and it all starts over again. Eventually, there is a puddle of gas on the ground and another in the intake system all ready to ignite if there is a backfire out either end.