Gas leak

[colab]

I'm leaking gas. resulting in a little puddle each time I come to a stop while the engine is still running. I can't tell where it's coming from.

Just had an 836 BigBore kit and a long travel cam shaft and air pods installed in my cb750. Could it have anything to do with more fuel travelling?

Any recommendations?

 

[colab]

Oh... forgot to mention. It's dripping near the bottom rear of the engine.

 

[locOleoN]

Oh... forgot to mention. It's dripping near the bottom rear of the engine.

Oh.. that motor is all fucked up now...
tell you what, I'll be a nice guy and take that motor off your hands and give you my running stock cb750f motor.. ;D ;D

ehhh.. just sounds like one of the float valves in on of the carbs is stuck, or worn out, or the float level needs to be adjusted.
At the bottom of each carb, a overflow tube runs to the back of the motor and lets the excess gas exit between the engine & the swingarm. You need to find out which carb is leaking.
- a short cut is to remove one overflow tube at a time to see which one is spilling gas into the tube... (or you can stick your head under the bike and see which tube is leaking then follow the tube back to the carb bowl...
Once you find out which carb is leaking, knock it with the end of a screw driver to loosen up any bit that may be stuck keeping the float valve open...

If you are lucky, and it stops leaking, then you are done.

Try that first...

Id also recommend putting an inline filter in between the fuel tap and the carbs.

 

[Mortikan]

Apparently I type to slow Noel got to the punch

Have you checked your carbs? lots of leaks happen involving floats/seals and other vaious items sticking. the gas if it's gas only has a short path to follow. petcock, if tight and no leaks hoses/connections to carbs or carbs them selves after that it's burned. I don't have a cb but I know the linkage's are notorious for leaking especially on the left side if sitting on the bike.

hope that helps good luck

 

[matt365]

As the other guys stated, so nothing new to contribute, but I have a question:

When you were getting your cam and big bore kit installed, how long were the carbs sitting dry for. I've had a set sitting for a winter before, and all the gaskets and o-rings started to crack and dry out - leaked like a siv.

 

[sgt. slick]

Just to add to this an not post a new thread, I ran into the same problem today. I had a little bit of fuel leak when I parked the bike so I took off the carbs an ran some carb cleaner through them, replaced the worn out hoses an, as many have mentioned, added an inline fuel filter. Now the gas in leaking in a constant flow an leaking into the air filter as well.

Any suggestions? ???

 

[matt365]

I'd start by taking the bowls off and seeing if the floats are stuck. Somethings got to be gummed up and stuck to have the fuel running into the box.

Diagnosing problems on the internet is next to impossible. It's just a guessing game.

I'd just tear down the carbs. I've tried the easy route of spraying carb cleaner down it's throat and revving up the bike on some older junkpiles I've worked on, but it'll never get the thick varnish out. Dissassemble and clean each part.

 

[locOleoN]

Check if there are any cracks along the shaft of the brass overflow tube in the float bowl.

Just today I encountered a float bowl that had a thin crack in the brass along the length of the tube.

So no matter what you set the float level at, or how new the float valve or gaskets is, its gonna leak throught the crack into the rubber overflow tube...

 

[sgt. slick]

Thanks guys. the carb that was giving me problems had this black gue along the inside. my first time working on carbs an was a little intimidated. but it's either learn or pay someone else an hope they do it right.