Topic: 75 550k fuel leak?

[apex_seeking]

I added the question mark because I don't know if it qualifies as a leak. Ever since I got the bike on the road this spring, I've noticed "Gretchen" is leaving a little spot of gas from the #2 carb overflow tube on the ground. She didn't do this last year. I did rebuild the carbs over the winter. Any suggestions? Should I be concerned? It's only if I leave the petcock on and she sits for a day or so.

[Gordon]

It's not uncommon for these old bikes to dribble a little gas if the petcock is left on when the bike is sitting, and there's a very easy solution to this. 

Don't leave the petcock on when the bike is sitting.


Seriously, though, make turning off the petcock part of your shut-down routine.  It's a very good habit to get into.  If something causes one or more of your float valves to stick open, you could end up spilling the entire contents of your gas tank on the ground, or possibly even into the crankcase. 

[apex_seeking]

And that's exactly what I've started doing. Just wondering why. You say a sticking float. Could I have set a float level wrong? It doesn't bother me that much. More of a curiosity and trying to understand the nuances of these old bikes.

[Gordon]

Many things could cause a float bowl to overflow,  but a small dribble over the course of several hours or days is most likely either a small piece of debris in the needle valve, or a valve that's just not making a perfect seal, or an incorrectly set float level, or excessive friction between the float bracket and its hinge pin, or a hairline crack in the overflow standpipe. 

[apex_seeking]

OK....I think I'll just close the petcock and pretend there isn't a problem 

[Duanob]

When was the last time you took the carbs off and cleaned them? It's something to do with the floats. Either the float has becomes gas logged or has a leak or the float needle has some crud on it and not closing completely or your float needles are wearing out and not seating perfectly in the valve. I would say crud on the needle or in the valve.

Does your bike have a slight miss every now then? Just curious cause mine does and I'm thinking it's related to the float. Possibly gas-logged and sinking slightly. Just looking for similar symptoms and cures.

[strynboen]

i have some fine rust in the tank..the inline filter can not take it..it makes kabs overflote..have faund an better tank on germen e bay..så hope that helps..so tjek for rust..

[apex_seeking]

No missing or anything. The bike actually runs like a top. I tool the carbs apart and cleand them and replaced all the rubber over the winter. I didn't replace floats as mine looked ok. I checked float heigth and all seemed on the up and up. I haven't had much of a chance to ride it this week so I can't give much follow up, yet.