Air Leak

intheclear

New Member
Local time
6:48 PM
Joined
Sep 12, 2011
Messages
29
Location
Evanston, Illinois
Hi.
I'm pretty sure my carb is bottomed out according to the measurements I took, but this carb is still kind of a loose fit. When I spray starter fluid at the valve, the engine stalls, so this suggests to me there is a leak. The idle is still somewhat high, but I've managed to get it down some. Is there anything I can use to seal the carb, that I could buy from my local hardware store?
I've experienced the engine running well until I went over a rocky road one day and the idle bumped up again...
Thanks
-Greg
 
normally if you spray starting fluid at an air leak the engine will rev up, not stall. (unless you spray a whole bunch of it)
You can try adding an o-ring into the intake side throat of the carb.
this o'ring slides into the carb, and when the carb is put back onto the intake manifold, the o-ring will seal the gap. just make sure the carb is bottomed out on the intake so the intake is up against the o-ring.
 
I had to do an Extendo carb on my build and had leak used silicone and fixed,but my carb doesnt get hot due to using Hi heat tubing to xtend. do you have an external choke. if so check the tension.
 
normally if you spray starting fluid at an air leak the engine will rev up, not stall. (unless you spray a whole bunch of it)
You can try adding an o-ring into the intake side throat of the carb.

-I bought starting fluid at my local gas station... i didn't spray a lot, I thought...
just a quick direct burst.

I had to do an Extendo carb on my build and had leak used silicone and fixed,but my carb doesnt get hot due to using Hi heat tubing to xtend. do you have an external choke. if so check the tension.
I think I have an internal choke. Its built into the carb.
-
also check the intake manifold gasket. they are known to blow out quickly.
The intake manifold is fine.

Tomorrow I'll try to get an o-ring at my hardware store. Thanks for the info, people.
 
silicone? gasket goo? stag? some paper/cardboard? when theres nothing else handy, thick enamel paint?

thems my ideas :)

o-rings need a groove to sit in...

file the faces of the manifolds flat.

measure the depth op the socket on the carb. mark the depth on the manifold. make sure it is going full depth...

squashed bugs, mixed in a paste ;) (or shellac)
 
The o-ring made the idle go down quite a bit, but it still seems a tad bit high. My bike also runs with the choke fully off now, FINALLY. the idle screw doesn't seem to do much to the idle speed though... it stays the same or bogs down. I think my throttle adjustments are fine, it seems to me that the spring snaps it all the way closed... hmm
 
are you oisitive that you have the carb slide installed right?
it can go into the carb 2 different ways, but only one way is correct.
there's a long slot and a short slot in the slide.
the short slot goes towards the idle screw and the long slot lines up with a pin that should be on the inside of the carb straight across from the idle screw.
if you have the long slot lined up with the idle screw, the idle screw will not have anything to seat against to raise / lower the slide to adjust the idle.
if the long slot is lined up with the idle screw, the skide will drop all the way down into the carb.
BUT, normally if the slide is in wrong, you will either have no throttle response when you twist the throttle or it will be stuck wide open.
 
are you oisitive that you have the carb slide installed right?

BUT, normally if the slide is in wrong, you will either have no throttle response when you twist the throttle or it will be stuck wide open.

I don't think so. When I take the carburetor off and look inside, the idle screw does move the slide incrementally up and down, and also the throttle works very smoothly. I was careful when I installed the slide. However, the idle still is not very sensitive to the screw.
A few more pieces of info-
On a cold start, the bike won't idle. I have to turn the screw in to get it to idle.
Then the engine heats up and the idle runs a bit higher, and I can back the screw out a lot without affecting the idle, and if I go too far, the engine dies.
 
Back
Top