Talking to a buddy of mine (who is a carb guru) today about this problem. He's seen this a few times and, in his case, fixed it.

As you all know the float needle valve sits in the needle valve seat. The seat is removable and is sealed into the carb body by an O-ring. In his cases, the O-ring had deteriorated to the point where either gas would flow around the O-ring or caused the seat to be misaligned and the valve did not seat properly in the seat. In either case, this means that although the float works normally, gas flow cannot be turned off and the gas flows through the seat area. He found that once the O-ring was replaced the symptoms disappeared.

I’d like to challenge those of you who have this problem to try this cheap fix to see if it works.

Doc

DocShadow wrote:

As you all know the float needle valve sits in the needle valve seat.

Doc

Mighty big assumption there buddy.

I'm curious as well if this will cure it.

Thanks for the tip. Does this have anything to do with the carb boiling sounds as well?

I am goona go with Doc on this one...

Just messin with an O-ring can cause it to lose its seal....in fact in a lot of

mechanical disassembly /reassembly situations... new O-rings are recommended<br><br>Post edited by: Pop Rivet, at: 2007/04/18 18:25

Doc is probably right on this O-ring issue. It makes sense! (I didn't know there was a O-ring in a Roadie needle/seat assembly.) I would have assumed they used an alloy or copper washer, like the Japs used on older Datsun carbs.
Good point Doc!


OH! There's one VERY IMPORTANT thing about O-rings! They need to be assembled with some kind of inert lubrication stuff. O-rings can tear or shred easily when assembly is screwed in place dry.
Don't use cheap generic O-rings for fuels, (I almost had a fire on my propane BBQ because the propane promptly ate the new el'cheapo GENERIC O-ring I installed on the POL fitting.)

Post edited by: StarMyram, at: 2007/04/18 20:06 <br><br>Post edited by: StarMyram, at: 2007/04/18 20:10

I don't know ... mine did it when it was a week old... pre modifications... then didn't do it for a long time...

the only common factor was when the bike was HOT and I shut down the motor and without allowing it to cool restarted it... doesn't do it when I keep it running and she's hot...

if it was a leaking O-ring I'd expect it to do it either all the time or when the bike is cold and hasn't been run for the winter... (ie dried out and shrunk)
I think there are many factors that will cause you bike to puke fuel... some being the float bowl height... some could be this O-ring... some I think may be percolation ... some may be stuck needle valve... some may be fuel pump not shutting off

So I think we're coming up with a fix algorhythm IE: your bike pukes... 1st tap side of carb bowl to see if float valve is stuck open... 2nd check to see if you fuel pump is shutting off properly... 3rd check float hight ... 4th check O-ring and needle valve obstruction... 5th turn off petcock before shutting down bike when bike is hot and start bike with petcock off then turn on...

~Guido

davehrn wrote:
I think there are many factors that will cause you bike to puke fuel... some being the float bowl height... some could be this O-ring... some I think may be percolation ... some may be stuck needle valve... some may be fuel pump not shutting off

I agree completely. The symptom may reflect different problems so different fixes may be required. If you read thorugh the various posts you can see summer/winter gas, fuel percolation, stuck float, etc.

So I think we're coming up with a fix algorhythm IE: your bike pukes... 1st tap side of carb bowl to see if float valve is stuck open... 2nd check to see if you fuel pump is shutting off properly... 3rd check float hight ... 4th check O-ring and needle valve obstruction... 5th turn off petcock before shutting down bike when bike is hot and start bike with petcock off then turn on...

Certainly could be something like this. The service manual electical go/no go flowcharts are based this way.

Doc

DocShadow wrote:
davehrn wrote:
I think there are many factors that will cause you bike to puke fuel... some being the float bowl height... some could be this O-ring... some I think may be percolation ... some may be stuck needle valve... some may be fuel pump not shutting off

I agree completely. The symptom may reflect different problems so different fixes may be required. If you read thorugh the various posts you can see summer/winter gas, fuel percolation, stuck float, etc.

So I think we're coming up with a fix algorhythm IE: your bike pukes... 1st tap side of carb bowl to see if float valve is stuck open... 2nd check to see if you fuel pump is shutting off properly... 3rd check float hight ... 4th check O-ring and needle valve obstruction... 5th turn off petcock before shutting down bike when bike is hot and start bike with petcock off then turn on...

Certainly could be something like this. The service manual electical go/no go flowcharts are based this way.

Doc

I also agree that there may be many fixes as well. I am also leaning toward the float level is not set correctly to begin with. I had mine lowered during my first service. So far I have put a little over 300 miles since then. To date, no more puking, no more boiling sounds in the carb when it is shut down (it only did the boiling sound one time). I just got in from doing about 50 miles and stopped about half way out and shut the bike down for this very issue. Let her sit for a bit and then refired her up. Bingo, fires instantly. She seems to run a whole lot better since this adjustment. Just my opinion.

I also agree on the float level. I bought my 06 new last July and it has acted many times. I changed the float level 500 miles ago and it has not acted up since. I have 9000 miles on her now and love this bike. Even on warm days like 80 it has not acted up. I am really hoping I have fixed it. I put the clear hose on it first and had the bike sitting upright. The gas was 1/2 inch higher than the seem on the carb. I have it only 2 mm higher now. My gas milage did not change either. Maybe this helps.
Coolage

well i have had it happen to me two times, both times it was over 80 deg.s outside, and i figured two times was two many, so i got a peace of 1/8&quot; galv. sheet metal and made a shield to go around the bottom and sides of the carb. it took a little while to get it right for the mounting locations and i put a small o ring under the metal before mounting it to damping the shield. i then removed it and rounded of all of the sharp edges, painted it black after soaking the metal in vinager overnight for adhestion of the paint. i put it back in and havn't had the problem sence, hell i cant really even see it in there unless im looking for it. i also havnt had any rattling from it being in there, so im wandering if the fuel companys are putting something in the gas that they wern't last year to water down the fuel and make an even better proffet this year, the bastards!!! , and maybe that is why the problem is so wide spread with so many bikes infected. i talked to a frend with a honda shadow and he said his bike did it once this year to, his bike never did it before. so it may not be just the roadstars affected. <br><br>Post edited by: dozer, at: 2007/04/20 07:06