Petcock Leak in the Off Position

[CaptonZap]

Perhaps my initial question should have been more succinct. Something like: Has anybody ever had fuel leak past their petcocks in the off position and why?

II have noticed that not every thread is a question that needs an answer. Sometimes it is cool to be able to vent about a problem and find out if anyone has had a similar difficulty. I kinda thought that is one of the things these forums are about...



See ya!

You will have to excuse Sufferin in Texas. The heat makes him grouchy.
Here is a thought. Take your petcocks apart and look at the rubber washers in there. Are they cracked, deformed, worn in spots?
If you were almost down to the reserve point, and the washers allowed leakage from the mains to the output port, they would leak down till they hit the reserve level, and then quit. Or you could pour in a gallon, and see if they still don't leak.
Most problems respond well to a close visual examination.

CZ

[SFerinTEXAS]

You will have to excuse Sufferin in Texas. The heat makes him grouchy.

Actually it was one too many. But man IS sure Hot here.Record heat + a record drought .

[Shacknasty]

I figured you were feeling a little froggy down there in Texas! I thought yer cryptic remarks were kinda funny.

I will pull those carbs manana and see what's up. I'll let ya know what I see in there...

[SFerinTEXAS]

Before you tear into them set them on a bench and fill with fuel. That will show which one(s) are leaking and deserve added attention.And remember to check the metal floats for leaks. Looks like a 79 in the pic.

[Shacknasty]

Damn good thinking, I was only gonna hook up a fuel line to test after I was done cleaning to see if I had done it right. Your way means that I know exactly where to look. I'll probably still clean them all just to be safe. I hope my float isn't fulla gas.

Yup it's a 79 SF, and I've enjoyed every ride on it!

[natemoen]

Damn good thinking, I was only gonna hook up a fuel line to test after I was done cleaning to see if I had done it right. Your way means that I know exactly where to look. I'll probably still clean them all just to be safe. I hope my float isn't fulla gas.

Yup it's a 79 SF, and I've enjoyed every ride on it!

If you didn't know I will tell you. To test the brass floats boil some water and then take the water off the stove. Completely submerge the float in the got water. If there are any leaks you will see a stream of bubbles coming out of the hole.

[SFerinTEXAS]

Ive always been a bit leery of the boiling water test. If done wrong it can cause a leak.In this case since the problem is current a float that is sinking should be detectable by shaking it or dropping it in a small jar of gas.

[natemoen]

That temp water should not melt the solder used on the floats.

[SFerinTEXAS]

Not a matter of solder melting, its about the pressure build up internally that could pop a solder point loose. This would start the moment they go into the water.Could happen.

The hot water is the only quick test, my not quick test involves submerging them in gas for a good while.see if any enters. If so then the hot water to find the spot.

Again since this would be a current issue if it is an issue it should be obvious just by floating them in gas as they barely float as is with the rest of the non floating parts of the float attached.

[cywelchjr]

If 212 deg will pop the float joints, they are already bad and need replaced as with the bike sitting in the sun it's possible for temps to exceed that at times inside the carbs if dry. Any part on the bike that can't take 212 deg needs to be replaced (I'm not counting the rider), as sitting in the sun those temps can easily be achieved or exceeded, not in liquid gas of course, but if the carbs are dry, at least here in Ca the metal parts on my bike that are exposed to the sun exceed that temp on hot days.

[Shacknasty]

Well the floats were all good and no sediment in the bowls, nothing looked particularly dirty but I pulled everything apart and tossed the jets in the carb dunk. I'll clean the bodies and passages with spray carb cleaner. This is just routine maintenance on a bike this old. Gotta pay if ya wanta play!

Drained the tank and gonna give the petcocks and filters a good clean up, maybe even give the underside of the tank a wash and wax.

But the real question now, is about my idle mix screws. The wear on all of them is significant. Are they somehow repairable or do I go straight to replacement.

[cywelchjr]

I'm not sure cause I have the late style carbs and the mixture screws on them are slightly blunt by design, but I think those are supposed to be needle sharp, those might be broken off. Did you check that the tips aren't still in the holes in the carb throat?

[Shacknasty]

The holes are open and do not look worn. All clear!

[mr_misfit138]

Petcock leak

As for the leaking petcock in the off position, my dad had the same problem on his '81 Special. Turns out it was the petcock valve that wore out over the years. If you disassemble the petcock, between the switch and the main body there's a little plastic circle with 4 holes in it. I'd take a close look at that. It might look ok at a quick glance, but if any of the edges on those holes are rounded over a little bit, it could be your culprit. I'm not sure if how long my dad stored his bike for expedited the wear or not, but these little plastic parts are over 30 years old and constantly sitting in gas. I would wear out under those conditions. But, then again, I wear out walking up big flights of stairs.

Anyway, if that's your problem, the replacement parts weren't too expensive, and it's an easy fix. I think we spent like $10-$15 per petcock for the valves and the seal, but I don't remember where. It was a few years back. I'm sure you can find them though.

Hope this helps!

[skids]

Those pilot jets look pretty good to me.