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Fuel Leaking *from* Idle Air Screw?!?!

Featured Replies

Trialtrial, please post a pic of the carb mounted on your bike. I'm curious about how you route the overflow pipe from the bottom of the floatbowl.

  • Author

My Oko with the clear bowl has the fuel level quite a bit lower than that, how are the floats adjusted compared to how splatshop shows?

You may have damage on the Viton tip of the float needle causing it to not seal properly if the floats are set to their recommendation & the level is still this high

Well, this here is the problem. If I set it up according to the splatshop's recommendation, the fuel level is as in picture 1 above - IOW, the fuel level is above the rim of the float bowl.

I guess I have a problem with the float/needle - I will get a new one and see how it goes.

Thanks everyone for your help and recommendations.

Edited by trialtrial

If you carb has a drain screw and a small spigot on the bottom of the float bowl, then connect a clear hose the the spigot and run it up the side of the carb

Open the drain screw and see where the fuel level is

I have an issue with static setting of the tab on the float tang

It does not give you a specific reading of where the fuel is in the carb when it is fully assembled

Where did you get the clear float bowl ? Keihins do seem to run with a lot of fuel in the bowl, they certainly spill more than a dellorto, but when mine overflows it comes out of the overflow via the brass tube 'b' in your first pic

  • Author

Where did you get the clear float bowl ? Keihins do seem to run with a lot of fuel in the bowl, they certainly spill more than a dellorto, but when mine overflows it comes out of the overflow via the brass tube 'b' in your first pic

Its an OKO float bowl, got it from scooter shop from ebay. Thing leaks bad, but is useful for looking at float action and fuel level in the shop.

  • Author

I got a brand new float and valve. Adjusted it according to splat shop recommendation... and... its the same as the old one. Fuel level to the rim. Perhaps this is normal?!?!

Try and blow up the overflow tube to make sure its not blocked. Is there fuel going through to filter box out of rear of carb ?

Where did you get the clear float bowl ? Keihins do seem to run with a lot of fuel in the bowl, they certainly spill more than a dellorto, but when mine overflows it comes out of the overflow via the brass tube 'b' in your first pic

The Dellorto PH series doesn't have an overflow, Just a breather. I love the Dellorto reliability too!

I'm not sure on how much fuel should be in the float bowl, Never really needed to check but I'm curious now.

I can not understand how it's coming out of the air screw. Maybe a blockage in the air passage on the engine side of the slide messing up the pilot circuit.

I suggest getting some tamper proof torx bits and giving the jet tower passages a good clean as the holes are minute and easily blocked.

I love the Keihin performance but have spent more time fiddling and setting them up than anything. I can probably strip and rebuild one with my eyes closed now! I need to get out more :wall:

  • 1 year later...

Did you manage to fix the leaking issue? I've got a brand new KTM Freeride 250R bike which has exactly the same carb. The carb started to leak around the air screw after about 30 hours.

 

I added an o-ring and a washer just at the end of the air screw, and what happened is that the bike cannot get even started when cold, and when it finally starts up it stalls often when idling - I have to support it by a bit of throttle. When hot, it stalls when riding downhill :(

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