Small hole in carb body under the felt washers for throttle plate

[pjlogue]

Does anyone know the purpose of the small hole in the carb body that is under the felt washers for the throttle plate rod? This is off a '76 GL1000. The hole is a direct passage to the carb bore just upstream of the throttle plate.

I'm rebuilding a set of carbs and noticed the hole when I replaced the felt washers.

-P.

[Whiskerfish]

hmmmmmmm..... Nope. I try not to go that deep.

[pjlogue]

The only I can think of that would make sense is to draw air through the felt when the throttle is opened so it would help dry out the felt if it gets wet. However, none of the components the felt is in contact with would rust. Carb body, throttle plate shaft, throttle plats are either aluminum or brass.

-P.

[gltriker]

Here's my thought.

Maybe 7 -8 years ago I'd spotted a dark , slightly sticky film accumulated around the throttle shaft and felt dust seal on my 75 Gl1000's carburetor #3. That cylinder's spark plug color appearance suggested it was running 'richer' than the other 3 cylinders.

I reckoned it wasn't a problem because the sticky film wasn't affecting the free rotation of the throttle shaft/throttle plate.
I figure the residue is just the condensate of the liqutd gasoline that is evaporating out of the carburetor fuel bowl after the "hot' engine/carburetors is shut down. The residue MIGHT provide a source of lubrication film to the area of interest, as well?

I would imagine the same gasoline condensate residue would be found under the brass seal on the opposite end of the throttle shaft, as well. As long as the residue doesn't restrict the free rotation of the throttle shaft, I would say it"s ' normal'


viewtopic.php?p=821287#p821287

[robin1731]

That residue probably does nothing to lubricate. I've had plenty of carbs here that had that on the shafts and the shaft would not turn at all or barely move. Spraying carb cleaner into the throttle shaft bore while moving the throttle would loosen them up. Sometimes it would take quite a few attempts before getting all of the residue out. Even after ultrasonic cleaning.

[cfairweather]

According to CoPilot (They got the info from GoldWingDocs.Com): Summary: The design allows a tiny amount of air to enter the intake to provide proper air-fuel mixture and provides smooth operation. The felt is to prevent dirt from entering the intake.

[gltriker]

Just spotted this fellow's position on Keihin carburetor throttle shaft felt washers (dust seals) , again

https://www.motorcycleproject.com/text/felt_seals.html