Frame Petcock Rebuild


I noticed that there were yellow fuel drip stains coming down the left side of the frame, I didn't think much of it until one day I noticed a drop of fuel coming from the frame petcock. I paid a little more attention and noticed that the fuel was coming out of the left side of the petcock, the vacuum diaphragm seams. I was thinking about swapping to a CRF petcock that is common, but wanted to keep the vacuum feature. I went as far as buying a cheap Virago 250 petcock on eBay from China for $15, but the hose routing would have been messier. This thread got me thinking that if the round gasket is an off the shelf item for other bikes, the diaphragm must be as well.

I took a chance and ordered the K&L 18-2763 kit. The vacuum diaphragm was a perfect match. As was the valve gasket, O-ring and diaphragm spring. The grey plastic spacer that sits between the two halves of the vacuum diaphragm is reused. It's an easy replacement. I used two needle nose vice grips to clap the ON and RES fuel lines and unbolted the 2 frame bolts. Then leaving all the hoses on, I removed the 5 screws on the diaphragm side (proper JIS screwdrivers help). Some fuel will come out, but if the inputs are clamped, the tank won't keep draining on you. You'll need to pull the old diaphragm out through the middle of the grey plastic spacer, then carefully put the new one back in. Bolt it all back up and you're good to go.

My valve knob wasn't leaking, but I replaced that gasket and o-ring anyway. For that, you just remove the two diagonal screws and pull out the knob and cover. Use a pick of small screw driver to get the rubber gasket out. Replace with the fresh one.


The vacuum diaphragm might have the alignment pin holes at a different place than the above 2001/02 model. I find it hard to believe that it would be different, but is possible.