"Those IM Screw Covers"

[boyat68]

I noticed that the brass IM (Idle Mixture) screw covers on my 80G has a small hole in them, (makes drilling and removing easier). The pertinent question is, are the holes necessary to allow air into the mixture? I noticed that the replacement covers on Mikes has holes in them too.

I know that it has been said that you need not replace those caps when doing the deed, but I was going to put the extracted brass caps back in the holes and seal the drill hole with hot glue to keep out dirt after synching, but if the "Air Hole" is necessary I will not do it.

[81xsproject]

No air involved with the screw/cap. However, I wouldn't seal them off with glue. Maybe you could thread them to take a screw in bolt/cap.

[boyat68]

I have them so that they take a sheet metal screw, but the hole is rather large and would allow junk to drop down in them. The hot glue would only seal the hole for the sheet metal screw. Am I being to anal rententive? Never ran across a fuel port that was open on top. Of course leaving them open has its positive, you can introduce a little WD-40 at intervals.

[TopCatGr58]

Hey again Boyat68,

The IM screw is an actual fuel/air mixture control, and the fuel and air is being mixed before it gets to that point, so the screw is just metering that flow into the carb throat. Folks have expressed concern about dirt, water, etc. possibly getting down in that tunnel once the caps are removed. IF you got some carb kits, they may have come with the pilot jet rubber caps, it has been suggested to use them IF you don't need them for the pilot jet towers!

If you didn't get them but would like to, MikesXS has them:

Rubber pilot jet Passage Plug
Rubber pilot jet Passage Plug (Pk./2) Fits: XS650G/H/SH/SJ/SK/SL (1980-84)
stock Mikuni BS34 CV Carbs. Used inside float bowl to seal pilot jet passage -
1 used per carb


Part #48-5002 $3.00 USD /Pk/2

Don't know if WD-40 would be good? I would think the rubber O-rings under the screws are Neoprene/buna-n type, but not totally sure?!
But many folks just leave theirs open! Depends on how dirty the environment you ride in, whether it's garaged or stored outside!
T.C.

[mro]

Never had a problem leaving em "expossed"
and ride rain/shine etc..


mro