Fuel dripping from FCR/hard starting

[DOHCFOX]

Good morning all,

I noticed that, after cleaning up the fcr carb on my KTM 625, that a small amount of fuel is dripping (at a very slow rate) from the fuel overflow. It goes without saying that I need to address the leak, but would this leak also cause the bike to be even more difficult to start than normal? It does start, and it runs well. Thanks for the input!

[William1]

Yes, it would tend to flood the engine and make it too rich, esp. at idle. Service the float needle valve. until then, you can try this:

Open the petcock for just a few seconds. Close it. Start the bike, then open the petcock.

[DOHCFOX]

Thanks William!  Once the bike is idling it runs fine.  I do think, as you suggested, that it is flooding when I first go to start it.  I'll get to tearing the carb out this weekend.

[William1]

If the float needle tip looks good (no grooving and still 'pliable') you can polish the seat using a fat Q tip and tooth polish.

[tonybike]

Nice write up. I like your two extra ideas about polishing the seat and the workaround with the petcock. Thanks.

I had a crusty green deposit that needed to be cleaned off the seat. I don't know what it was. It was hard to get off but a drop of water seemed to dissolve it. I was thinking it was from the ethanol in the gas.

[FORMA MOTO]

Nice write up. I like your two extra ideas about polishing the seat and the workaround with the petcock. Thanks.

I had a crusty green deposit that needed to be cleaned off the seat. I don't know what it was. It was hard to get off but a drop of water seemed to dissolve it. I was thinking it was from the ethanol in the gas.

 

it was

 

You have to treat all gas all the time for ethanol contamination

[DOHCFOX]

So I finally got to taking the carb out of the bike to inspect the float valve. The needle tip is still pliable with no grooves, and the inside of the valve seat is clean and not corroded. I pulled the float valve seat out and discovered an o-ring in pretty crusty and crappie shape. Any possibility that the o-ring be the culprit? See attached photo...

[DOHCFOX]

[William1]

Yup, common fail part. Under $3.00

Yamaha PN (Same part on all bikes if your KTOOM guy does not have it handy)

8F2-14147-00

[DOHCFOX]

Again, thank you William!