Getting gassy

[Joe McBride]

Hi: The snow riding in the snowbound and bored trail makes me want to ride. I have a feeling that is a bad idea. I noticed a gassy smell in my garage and had to investigate among my toys and tools to figure out the source. It looks like my 97 DR350 is leaking gas. The manual says to leave the petcock on as it is a vacuum system. The three positions for the petcock are on, PRI (prime?) and reserve. With the cold and life in general I have not had the chance to check my oil or anything else, but at a glance it looks like the source is around the shifter. This makes me think the vacuum system failed and the gas leaked into the engine and into the crankcase. So I am thinking I need to drain and replace the oil.

Does this all add up? Any ideas on how to fix the petcock?

Thanks

[troy]

Sorry to hear about your gas problem. First off, I'd suggest you refrain from smoking while working on the bike.

I can confirm that the DR350 petcock does not have an off position. Supposedly it is off until the engine pulls vacuum. I've not heard of them going bad, but I can tell you that the vacuum petcock is not vital to the engine operation. I had an aftermarket tank with a "normal" petcock and the bike still works--that is, gas still gets to the carb and it runs.

So if you can replace the petcock, I guess you don't have to go back with a vacuum one....although personally I probably would.

[Hank Moody]

I had the same problem but mine was due to the cold temps. The rubber gasket between the petcock and gas tank had a problem with "shrinkage". I was able to get a 1/4 turn on the bolts and it stopped.

It might be worth a quick check to see if that is your problem.

[slimtrader]

I had the vacuume petcock go bad on my DRZ. I was riding in MN and the bike quit like it was out of gas. Tried to start it till the battery was dead and then swapped batteries to start it. Didn't think I was that low on gas but I topped off anyhow and the problem persisted. Someone suggested running it on Prime and that did the trick. Worked fine the rest of the day. So when mine broke it left me with no or little fuel. I replaced the petcock and it was fine after that.

I'd be more apt to believe the fuel is leaking somewhere on the outside of the bike and dripping off of the lowest point. If it was leaking into the crankcase it would just stay there, right? Unless you had a known oil leak around the shifter before the gas was noticed. I think Mr. Moody has this one pegged.

[safiri]

The vacuum operated valve is there for safety. If the engine stops, fuel is shut off. That said, that vacuum valve is one more thing that can go wrong. Troubleshooting it is a PITA, especially in the woods. I would price both an OEM fix kit as well as a non-vacuum replacement. Neither of my KTMs came with one, and the LC4 was an OEM DS bike.

The only way for the fuel to get from the tank into the engine is through the carb. If your float isn't working, then it can allow the float bowl to overfill and this fuel then run into the engine through the intake valve. If that is the case, then you need to change the oil as well as adjust the float (or fix the float valve). No fuel should run into the carb when the float bowl is full.

I agree with Mr. Moody (and isn't he!) that the gas is acting as a solvent and cleaning the exterior of your engine for you.

If gas is in the oil, you will smell it on the dipstick.

[MacWildcat]

I have had 3 suzukis, all 3 had the vacuum petcock go bad - gas always flowing. I lucked out on the first two bikes and the float valve held. Not so lucky on the third bike. Petcock failed and float valve failed, filled the engine with gas. On two other separate occasions I have witnessed this same mishap on someone else's bikes. One was brand new bike!

I decided it's not worth the risk. A OEM replacement is big $$, so is the rebuild kit. For under 20 bucks you can replace it with a manual petcock that will give you the piece of mind that the gas is really off. A yamaha dealer matched a petcock from a four-wheeler that was almost a exact match to the Suzuki OEM piece of crap.

BTW - when the petcocks failed on the other two guys bikes.... they had driven 6+ hours for a weekend ride. Ended both their weekends before the weekend even started.

Be sure you track down that gas leak before you ever try starting the bike. Check the oil and pull the spark plug in case the cylinder is full of gas.

[Joe McBride]

All good ideas. I'll check it out tonight and stop eating so many beans
I do have a spare plastic tank with a petcock on it so I have a temporary solution in hand should the petcock be bad. Will advise. Thanks!