Petcock valve mod - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
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post #1 of 2 (permalink) Old 03-20-2018, 07:11 AM Thread Starter
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Petcock valve mod

I did this mod because I was tired of the old valve leaking and filling my crank case up with gas, also the rebuild kits and replacement valves are so expensive. This does not do anything to the sealing part of the petcock, mine was working well, this only deletes the vacuum portion of the petcock that is so prone to failing and either not allowing fuel to the carbs or leaking through and filing the crank case up with gas.

I can't tell you where to find the material, I was lucky enough to find some scrap pieces at work and use that. I used a piece of about 3/16" thick rubber gasket material. I would think you could use anything as long as it is resistant to gas. You may even be able to do this without it and just seal the 2 pieces with ultra black RTV sealant, I don't know just sharing what I did. Also you will need a M6 bolt/screw to plug the vacuum port.

1. After the petcock is removed (actually did one with the valve on the tank turned on it's side) remove the 4 phillips head screws from the vacuum diaphragm side of the petcock.
2. Completely remove the vacuum diaphragm and spring assembly.
3. While the back cover is off, using an 8mm wrench, remove the brass hose nipple careful not to lose the tiny check valve that is inside. Replace the nipple with the M6 bolt.
4. I used the back plate as a template and cut a square out of my rubber gasket material, marked my holes, and drilled them out. Doesn't have to be pretty, you can trim it later.
5. Lastly just assemble the valve back together with the gasket you just made, tightening the phillips head screws in a criss cross pattern so it seats evenly.

I didn't take any pictures in the process, but here is a picture of the finished product as well as the parts used because I made extra to do another valve at home. This is a quick and easy solution to these problematic valves. Hope this helps someone else. This is the valve from my 85, with red primer over spray.

Petcock by lugnut1009, on Flickr
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- 1999 Kawasaki Vulcan 750
Ear shaved
Mufflers removed / 38/140 + 2 shims
Relay coil mod
Pick-up coil mod
Emissions removed
Lowered rear
Rear blinkers located in tail light housing
Petcock gutted

- Wife's: 2018 Can-am Spyder F3 Limited Pearl White
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post #2 of 2 (permalink) Old 03-20-2018, 10:30 AM
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+1 vote for sticky post!
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2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
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Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
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