blasted NOISY petcock!

[IanFrancisco]

Spent the last two weeks agonizing over a top end rattle that sounded like someone shaking a can of spray paint. Checked the valve clearances and measured the camchain for stretch - everything was within specs. Changed the oil and filter (Mobil1 10/40 motorcycle oil). Used a screwdriver as a stethoscope all over the engine and couldn't pinpoint the source of the noise. Didn't think to check the petcock because I just replaced the diaphragm with one from CRC2 about 500 miles ago. Reading posts here, found one that remarked about the noisy petcock. Did the screwdriver/stethoscope thing to the petcock - sure enough, rattling like crazy. Said to myself, if that's all it is, to hell with it - I'm going riding! Did about 120 miles including some 80mph freeway miles. Getting off the freeway to go home, the bike wouldn't idle right and misfired pulling away in first gear unless excessive amounts of throttle were used. Get home and find that the new petcock diaphragm has begun leaking big time, way worse than the old one. The metal washer that surrounds the plug/piston in the center of the diaphragm had rattled itself to pieces already. Started the engine with the tank off and sure enough, rattle gone, engine sounds sweet, like new! This petcock is fired, it's coming off and going in the parts box. I'm tempted to trash it but will save it for the day some collector wants to pay me $2000 for my 1980 GS450ST (haha). Buying a manual petcock from a PE250 on Ebay for $20. Will repost with results as to whether it fits and works. Anybody hearing any scary rattles coming from their bike, check the petcock first! I can't see why anyone would design a luxury/convenience item like a vacuum petcock to be such a mission-critical component of a bike. If it leaks or doesn't work right the bike runs like crap or not at all. Mine doesn't have the PRI position, it needs a perfectly working diaphragm to flow fuel in either ON or RES positions. What a pain in the @$$ !!!

[bgmart450]

The wife's S petcock knocks slightly, gets amplified by the tank, esp when its low on gas. Hard to hear otherwise with out getting real close to the tank.

Been thinking of getting a non-vacuum petcock for mine too. I'd like to hear how that works out for ya.

[Chris Daniel]

My 650 was doing the same thing, drove me nuts untill I figured out that the noise was the petcock. I replaced it with a Pingel and love it.

[earlfor]

Ohhhhh, I just love my little Pingel. I never leave home without it. :-) If you want to make the wife really happy Brent, give her a little Pingel.

Earl