Petcock issues

[chef1366]

That's very true, Bill, but the bolt spacing on it is 50mm.

Thanks Charles! I forgot about the minor detail.
Bite the bullet and get a Pingle.

[Suzuki_Don]

Spacer Made to Lower Fuel Tap

Last night I made a spacer to fit between the petcock flange and the petrol tank. The spacer needed to be 8mm thick to push the petcock down enough to clear the frame rail curve behind the carbs. I made the spacer from a piece of 8mm aluminium plate (actually one of Dan's caliper brackets. I knew they would come in handy for something one day.























That's all Folks!!

[chef1366]

Great work Don
Now seal that plate with some Hylomar. Works a treat!

[Suzuki_Don]

Great work Don
Now seal that plate with some Hylomar. Works a treat!

Thanks Bill. Not sure if we can get Hylomar here is OZ. So I went ahead and made a gasket from a rubberised cork gasket material which is resistent to petrol, oil, etc. according to the manufacturers spec. sheet.







By placing the 8mm spacer under the petcock it lowered the petcock so the two bulges on the vacuum plate did not contact the frame any more. But looking at the petcock from the vacuum side of the unit the screw at the top left was still touching the frame.

So I decided to countersink the hole in the cover and fit a 4mm countersunk screw, only one problem - I couldn't find one anywhere. So my friend Ron put a chamfer on a standard screw so it would fit in the countersunk position which lowered the screw enough to give the clearance that I needed.

The following pictures show what was done, although you will need to look hard at the photos to see it.

[faafaafowhigh]

My all stock GS750 has the "Dreaded 1980 Petcock" (nylon barrel screw no lever). After following the carb cleanup series to at "TEEEE" I still have fuel spitting back into my airbox. I will be purchasing a new petcock; however, i am unsure of which one to replace it with. Should I replace the dreaded one with the exact same dreaded OEM, or go to Z1 for their version of the dreaded one. I'm also curious what difference in materials if any between the two. Thank-you all in advance for your comments and advice.

I came to this diagnoise by switching petcock to prime and pinching off the vaccumm tube from petcock to carb #2.

[Suzuki_Don]

My all stock GS750 has the "Dreaded 1980 Petcock" (nylon barrel screw no lever). After following the carb cleanup series to at "TEEEE" I still have fuel spitting back into my airbox. I will be purchasing a new petcock; however, i am unsure of which one to replace it with. Should I replace the dreaded one with the exact same dreaded OEM, or go to Z1 for their version of the dreaded one. I'm also curious what difference in materials if any between the two. Thank-you all in advance for your comments and advice.

I came to this diagnoise by switching petcock to prime and pinching off the vaccumm tube from petcock to carb #2.

I am not sure fuel spitting back in the airbox is a symptom of a bad petcock. Sounds more like a high fuel level to me. Could be needles and seats or just incorrectly set floats.

If you are going to buy a new petcock I would get the one from Z1, but check first that it will fit. You need to know the distance centre to cente of the mounting bolts. Mine was 44mm. Some are 50mm. Also make sure the vacuum plate on the back of the tap does not foul the frame. I had to reverse the vacuum outlet so it faced forward instead of in reverse. Then as explained above had to lower the tap by 8mm using a spacer that I made up.

Mine was on a 550 frame and it could be the 750 frame is different in shape and will not cause these problems.