leaking petcock?

[B.B.]

ok still having problem. i know my petcocks r leaking and i am looking to rebuild the
in a week or two. with that said, i am having a prob with my carbs leaking fuel into the air box. When i start the bike it stops but the bike will idle high then drop to normal rpms until i rev it up and then it will stick again for a few sec. I thnk this is due to running rich. I clean carbs replaced valve seal and adjusted float hiegth. I am wondering if the petcocks leaking would cause this overflow. if not then what?

[cywelchjr]

Carbs leaking fuel into the airbox is NOT the petcocks. The petcocks shutting off only masks the problem in these cases which is that the needle valves in the carbs are leaking for one reason or another. Being an 80 special if you didn't replace the o-ring on the needle valve seats when you rebuilt the carbs that is very likely to be the problem as those flatten out over time and let gas run right around the outside of the seats totally bypassing the seats and making the carbs run rich.

That said, the running high and then dropping back after a bit is almost always caused by the carbs needing to by synced, which includes adjusting the idle mixture as part of the process, but you need to get the carbs in good working order first. That said, you may have leaky petcocks as well, but to have the carbs leaking requires that the carb needle valves ALSO be leaking at the same time, so you have TWO problems at a minimum, BOTH of which need to be fixed, although frankly IMHO the needle valve is the more important of the two, as it's the primary control valve for fuel and the only one in operation when the engine is running.

[B.B.]

hey cy thanks for the info. i just replaced the o-rings yesterday. the only other thing i can think of is float hiegth which i checked yesterday as well. any other suggestions?

[ManagerMike]

The floats themselves are known to hang on the bowl gaskets. The float valves themselves could be suspect as well, are THEY new? A Cy implied, the petcocks are supposed to flow with the engine running. If you have fuel running out while it's running, it can only be the floats or float valves.

[cywelchjr]

Actually if you have fuel running out at ALL you have something wrong with the needle valves. You may well also have something wrong with the petcocks if the engine is not running and they are off, and/or the octy if it's still in place.

[B.B.]

Yea I know my petcocks are bad they leak when i pull the tank. The carbs were leaking after i put them on the bike before i ever started the bike. I think the float is sticking since i started the bike and taped on the carbs and it stopped. it was leaking out the #2 and #4 carbs.

[cywelchjr]

There is an adjustment for how far the floats can drop down, and this can help stop them from sticking. Especially when tapping on them stops them from leaking that is often the issue. Were the petcocks set to the off position when the leaked when you took them off? (I'm guessing they were but I'm not going to assume anything on that).

[B.B.]

ok so which way do i adjust the floats. I know they should be 23mm when sitting normal, does it matter if they are different hieghts when turned upside down (or that would actually be right side up). And yes the petcocks were turned to off position. But thanks for asking that wouldn't be the first time.

[natemoen]

ok so which way do i adjust the floats. I know they should be 23mm when sitting normal, does it matter if they are different hieghts when turned upside down (or that would actually be right side up). And yes the petcocks were turned to off position. But thanks for asking that wouldn't be the first time.

When you turn them right side up it doesn't really matter but there is a second tab that sits next to one of the float posts that will stop the float from dropping down too far. That is the adjustment Cy is referring to and it will stop them from dropping down so far that the float needle gets cocked and won't seal.