idle mixture thread

[Crazcnuk]

Just wondering if anyone has ever determined if the idle mixture screws are a standard thread of some type.

I have two that chew up the idle mixture screwm and would like to chase them, if I can get a tap for it.

[red bandit]

6mm X .5mm IIRC it's not standard but it's common.

[DGXSER]

Not sure if it is the same on the BS34 type II and the type II that I have on my 81 or not. I know the screws mount up differently. The older type are exposed, the newer ones are down in the tunnel.

When I got my stuck screw out, I took my old mixture screws (ordered new in my kits) and used them as a "tap" to chase the threads. Used Blaster as a cutting oil, and slowly worked it back and forth until I got the threads cleared. I counted the turns to see that I got it all the way down. Tarzan had a good suggestion of cutting grooves in the threads vertically to make a gap for the crud to go into, like a normal tap. HTH

[Crazcnuk]

That is what I did with the last set of carbs, too.

However, with these, there seems to be a fair amount of aluuminum oxide in there, and I have wrecked the threads on two 'old' mixture screws, so far.

The 80-81's use different screws than the 78-79.

I was hoping the brass would be strong enough, but I guess not.

[DGXSER]

Not sure if this is the right size, but the tap is available.

http://www.amazon.com/6mm-High-Speed.../dp/B0006FI7TU

[DGXSER]

Update - found an old thread that confirmed the thread size for the later style carbs to be 6mm X .5 thread pitch.

Sound liek you have the early types? Not sure on those.

[Crazcnuk]

No, I have the late ones, the ones down in the tube.

Thanks for the info, I will try and find one of those!.

[DGXSER]

First reply has a link to one from Amazon, only $3.30 US. And it is in stock.

[oseaghdha]

This one is better.

Get you to the bottom.

[corey]

$3.30 is cheap for that odd ball tap. I think I had to pay ten or so for the same rig when I fixed my chewed up threads.... that was before our economic mud slide, though...


Be sure to go slow... those are tiny tiny threads... :S

[Crazcnuk]

I only need it to clean threads in the aluminum housing, so not a problem if it isn't the highest quality.

[xs1100rider]

tap

craz, my offer still stands to mail mine out to you. i sent you a message about it yesterday.good luck with the threads. my wife is dragging me off to south dakota this afternnoon and i won't be back till monday.

[Crazcnuk]

Thanks, I tried to source one out locally, yesterday, including our local Machine shop, but no luck.

If I can't find one by Monday, I may have to take you up on your offer.