How much gas smell is too much

[Guest]

Greetings,

I recently rebuilt my carbs with new o-rings from Cycleorings, Gunk dip/cleaning etc. using Paul Musser's tutorial... (Thank you Paul!). I set the float height. New bowl gaskets. I replaced one pilot fuel screw I accidently... I mean the PO accidently broke off in the carb. My 79 850 has VM carbs with the plastic fuel Tee and Rails... so no O rings there were replaced on these. Sealed up the air box... (which made a great difference) It runs pretty well... no carb sync yet... but still runs pretty well.

I have a strong gas smell.

There is no gas in the oil.

Petcock does not leak.

No visible leakage from fuel Tee or Rails or anywhere else under or on carbs.

There is a wet end on the rubber tubes down by the rear tire... but never a drip.

I took a combustible gas sniffer around the entire engine.. the key hole for the gas cap leaks vapor, The Fuel Tee and Rails leak vapor.

The smell is strongest inbetween the carbs and up under the rear of the tank by the tank-to-frame bolt. ... vapor rising and collecting?

I never see drips or stains when driving or parked over night except for the wet bottom of the tubes by the rear tire... but that is not where the smell is strong... it really creeps out around the bottom of the tank when sitting at a stop light.

I ordered a new Fuel Tee and Rails from Z1.

Any other suggestions while I have the carbs off again? And how much smell is acceptable?

Thanks
TP

[DannyMotor]

On my 78' I rebuilt and dipped, and I have an aluminum T in the middle with rubber coating, and rubber couplers between 1/2 and 3/4...

I have absolutely NO gas smell, ANYWHERE near the engine... petcock, fuel transfers, bowls, caps, or boots.. I do get a little out of the breathers (which is normal) and a little out of the over-flow tubes (also normal) but you've got to practically stick them up your nose to smell it.

The tank cap gets a little smell out of it, but that's because it's the vent and needs to suck in air as the gas level goes down.

Sounds to me you're on the right track getting new T's and connectors.

Again, you should have ZERO gas smell around the motor... even sticking your nose right up close... if you can smell gas from say 6+ inches away... there's an issue.

[hampshirehog]

Fuel gauge sender gasket weeping?

[BassCliff]

Hi,

Is the float height set properly? When setting the float height with the carbs upside down, a lower number will mean a higher level in the float bowls. I've always tried to set the height right in the middle of the range spec.


Thank you for your indulgence,

BassCliff

[twotimeGSr]

Well... since I'll have the carbs off to install the new Tee and connectors I might as well pop off the bowls and recheck my floats.

[derwood]

check float level wet before the carbs come off,
shows actual fuel level,
helps in diagnosing a leaky float valve, or heavy float

[BassCliff]

Hi,

check float level wet before the carbs come off

Yes, this is certainly more accurate.


Thank you for your indulgence,

BassCliff

[Buffalo Bill]

Could be it's OK…

Any chance, this is your first carbureted engine?
It's gonna evaporate gas after a ride, mucho on a hot day.

Actually after another read, it sounds like you're getting gas in the air box.
That means the bowl floats are too high, so gas is flooding out the carb intake horns.
Lower them a mite, and I'll bet that's the issue.
If that don't work, it could be the needle valve controlled by the floats has an issue

[BassCliff]

Hi,

Another thought; Make sure the tank is venting properly. There is a small hole in the filler neck which should be clear. Make sure the gas cap is venting properly and has a good rubber seal on it.


Thank you for your indulgence,

BassCliff

[twotimeGSr]

UPDATE.....

I worked on the bike today. I could not get the fuel level gauge in time to check the fuel level in the carbs to check before I removed them. (but I did order one) So, off with the tank and air box and then the carbs. I popped off the carb bowls first to re-check float height...... and... Hmmmmm.... I guess you are really supposed to tighten those bowls well, because mine were all not tight enough and gas was leaking between the gaskets and carb bodies. But I did check the float height and all were about a mm or two to0 low, so I went ahead and set them to the upper end.... and tightened them better than I did on the carb rebuild.

I also pulled the carbs apart and put in the new fuel rails and Tee I got from Z1. I had an issue getting the second o-rings to stay in the grouve so I swapped the second o-rings with the ones that came from CycleOrings which are just a bit thinner and they installed just fine.

Reassembled and put about 20 miles on it and NO GAS SMELL!


Thanks for all the suggestions,

TP

[chef1366]

I huff carbon monoxide so I wouldn't know.