Topic: gas leak from carbs

[pg13]

so i just got my bike running and my clutch fixed!!!! was warming it up hopefully to take it for a test ride when i noticed gas leaking from my #1 pod. i did carefully look that it was not coming from one of the fuel lines or anywhere else. took the pod off and gas dumped out. so what you all think? i was planning on a carb rebuild, just wasn't planning on it right now. any quick fix or something else it may be? also noticed a little rattle while it was running on the center stand. ideas?

[punch455]

Hey, what bike is it?  Did this happen with the choke closed?  If you have an accelerator circuit, I've had this happen by revvin it up too much with the choke closed.  The accelerator pump was squirting fuel against the choke plate and dumping it back into my filter. Where are you in Chicago?

[Cvillechopper]

Issue 1 - Gas leak.  Pull the carb bowl and make sure the float is moving freely and that the float valve and seat are clean.  You should be able to open the petcock and cut off fuel flow by raising the float so it closes the valve.  Also make sure your overflow tube (brass thing sticking up in the center of the bowl) is clear. That allows the gas to run out instead of flooding your filter or worse your engine.  Take care of this before you turn the petcock on again.  High risk to engine if not addressed.

Issue 2 - rattle.  Have you done a tune up on the bike (cam chain, valve, timing adjustments, fresh oil, etc)?  All of this needs to be done periodically and each could cause a noise of some sort.  Could also be something else but the tune up procedure is necessary for a well running bike so start there.

[Spanner 1]

The only reason there could be fuel backed-up into the pod would be the bloat bowl overfilling, either a stuck float or the needle valve not closing into the fuel nozzle.
Prob. 2nd option, due to crap stuck in the small opening the valve has to seat in.....

[pg13]

thanks for all the ideas. this is my first bike(CB750K4) so i am learning as i go. i have changed oil, oil filter, air filter(new pods), plugs. guess i have to look into cam chain, valve, timing adjustments and look to see if float is stuck. then onto carb rebuild. so much to do i can feel summer slipping away!!

punch455 i live on the north side the bike is at work downtown. U?

[Cvillechopper]

thanks for all the ideas. this is my first bike(CB750K4) so i am learning as i go. i have changed oil, oil filter, air filter(new pods), plugs. guess i have to look into cam chain, valve, timing adjustments and look to see if float is stuck. then onto carb rebuild. so much to do i can feel summer slipping away!!

punch455 i live on the north side the bike is at work downtown. U?

It's really not THAT bad.  First time you'll probably need a few hours to get the cam chain and valves adjusted.  Another hour or so to get the points gaped and timed (they are cheap to replace if there is any pitting but you still have to adjust them). 
Carbs will take you the most time.  If you haven't done so already you should pull the bowls and check the jets.  Unless they are dead clean you'll not get the bike to run right.  Also, you mentioned pods.  Were they on there when you bought the bike and you just replaced them?  If the carbs haven't been jetted correctly for the pods you'll have a crappy running machine. 
Take some pics and let us see what you're working with.

[RM81]

If your floats check out ok and you still have the gas leak, then check for cracks in the overflow tube.  There's some info about that in the CARB FAQ's.

http://forums.sohc4.net/index.php?topic=5410.msg245572#msg245572

[Cvillechopper]

If your floats check out ok and you still have the gas leak, then check for cracks in the overflow tube.  There's some info about that in the CARB FAQ's.

http://forums.sohc4.net/index.php?topic=5410.msg245572#msg245572

That would cause the gas to leak out the overflow tubes, not fill up until it floods the filter.  Great link though.  I'm dealing with that on my 350 twin build.

[RM81]

If your floats check out ok and you still have the gas leak, then check for cracks in the overflow tube.  There's some info about that in the CARB FAQ's.

http://forums.sohc4.net/index.php?topic=5410.msg245572#msg245572

That would cause the gas to leak out the overflow tubes, not fill up until it floods the filter.  Great link though.  I'm dealing with that on my 350 twin build.

yep, you're right.  Not sure how I missed that in the OP.  I thought it was leaking out the fuel line.

[pg13]

well i pulled that float bowl off and it is pretty clean actually. it seemed like it did stick a little when i first tried to move it up but only that time, then it was free and moved easy. so i think i'll move on to the cam chain. i read how the owners manual said to do it and i did just loosen and then tighten back with it at 15 degrees past TDC. but still have that rattling. is that it? loosen then tighten? well im off to get a set of feeler gauges so i can try to adjust the points and valves, then maybe i try the cam chain again and see where im at. thanks for any help

[punch455]

thanks for all the ideas. this is my first bike(CB750K4) so i am learning as i go. i have changed oil, oil filter, air filter(new pods), plugs. guess i have to look into cam chain, valve, timing adjustments and look to see if float is stuck. then onto carb rebuild. so much to do i can feel summer slipping away!!

punch455 i live on the north side the bike is at work downtown. U?

I'm at Foster and Milwaukee! If you get it running we should set up a little sohc Chicago outing yeah?  Plus, I have all the maintenance tools in my garage if you ever need anything.  Would love to check out the bike!

[OakBehringer]

I'm at Foster and Milwaukee! If you get it running we should set up a little sohc Chicago outing yeah?  Plus, I have all the maintenance tools in my garage if you ever need anything.  Would love to check out the bike!

My bike is currently in Park Ridge. We should have a superdawg meet. Start a thread and PM me, as I won't be watching this one

[cycleman]

Sometimes after a bike has sat for awhile and you start putting gas into the carbs the needle & seat will stick and the gas will run out the overflow tube.  Shut the gas off, tap the bowl of the affected carb gently with the plastic end of a screwdriver, and turn the gas back on.

Sometimes you have to do this a couple of times but if it's a minor issue this usually works.  Once the new gas gets flowing through the needle & seat area the problem usually goes away.  If this doesn't fix it, then I'd look at a good cleaning to see if that fixes it or a new needle & seat.

[OakBehringer]

Sometimes after a bike has sat for awhile and you start putting gas into the carbs the needle & seat will stick and the gas will run out the overflow tube.  Shut the gas off, tap the bowl of the affected carb gently with the plastic end of a screwdriver, and turn the gas back on.

Sometimes you have to do this a couple of times but if it's a minor issue this usually works.  Once the new gas gets flowing through the needle & seat area the problem usually goes away.  If this doesn't fix it, then I'd look at a good cleaning to see if that fixes it or a new needle & seat.

Good luck- you'll never fix it. I tap my carbs every time I turn the gas on if it's been sitting for more than a day.