Hi, I've got a 1986 xj700 maxim, and the petcock is not working correctly. It is supposed to be vaccum fed, but it allows gas to go to the carbs no matter what setting it is on. Does anyone have any tips on fixing them? I have put in a new diaphragm and that rubber disk with circles cut out of it. Thanks for the tips.
mrblades

If you didn't fix it with new rubber, I suggest streching the spring A LITTLE.
Or... you could try this link and see if it helps any at all.
http://s7.invisionfree.com/XJOWNERS/index.php?showtopic=84

Thanks eatatjoz for the tip. I might try it when I have it off next.
mrblades