air screw o-rings

[greg78gs750]

hi guys.

well, i pulled the carbs to clean them again, i just rebuilt them, oh, like 3 weeks ago with new o rings from mr barr. when i unscrewed the air screws, the brand new o rings on all 4 screws were all torn up and ripped!!! is there some trick to installing these screws? is it possible i got a bad batch? i mean, one of them was completely split around the circumference, all were unusable and really worse than the 30 year old ones i took off 3 weeks ago!! i guess im gonna email robert to order some more, but am i missing something? this motorcycle is trying to break my heart.

[chuckycheese]

Not right!

Well the first question is....Why did you pull them after having rebuilt them 3 weeks ago?? There's something else going on, for certain. How tight did you screw them in? Not all the way, I hope!! Let us know 'cause there's a simple explanation for what happened.....and it isn't Robert's "O" rings; they're good stuff...(I just ordered 2 more sets from him about 15 minutes ago.\\/)

[greg78gs750]

well, as my multiple posts recently have witnessed, i still have a cold 3 pipe. good spark. valves adjusted. air sealed. etc, etc, etc. screwed up my timing trying to check it, so dealing with that now. but it all led me back to my carbs, so i decided (since i am pretty familiar with them by now.....unfortunately) to dip them, again, for good measure.

i know roberts orings are good, didnt mean to question that. i thought the procedure on the screws was to set them 1 1/2 (or whatever the number is, i dont have it right in front of me) from lightly seated, much like the fuel screws. how else can you get them the right number of turns out? have i misunderstood the vm rebuild pages? i might have a parts bike available pretty soon if i keep up my bungling.

[Nessism]

Before installing the o-rings it helps to put a drop of oil or silicone grease on them first - keeps them from tearing during installation.

[SqDancerLynn1]

did you forget the little washer ?

[greg78gs750]

little washer? nothing i have seen concerning the screws on the vm's has a little washer on the air screw....at least not according to clymer or paul musser's vm rebuild pages....and no leftover parts either, i followed my photos putting everything back together. i think ness is right, i will try some lube on the new orings. i am gonna take a deep breath and try everything again. if i cant get my 3 pipe hot at idle this time i am either going to:

a. ride the crud out of it till it dies

b. go after it with a hammer

c. go after it with some wrenches and sell it for parts.

[chuckycheese]

Washers

Yeah, I thought about the washers but I don't think there's a chance that would have been the problem unless you really tightened and squished the screws in there. The washers are a good idea, for sure, but if they aren't there, I don't think that's the problem.

[SqDancerLynn1]

From end of needle should be O ring, washer, spring

[greg78gs750]

could you maybe point me to a picture or a parts diagram that shows these washers? cause nothing i have looked at, from parts fische to the rebuild papers to my manual has them anywhere...i want things to be right here. thanks!

[Nessism]

The washer business is applicable to BS/CV carbs, Greg's bike has VM carbs which does not have the washers (Unless I'm missing something).

Silicone grease, such as for use on brake system parts, works great for the o-rings since it doesn't hurt rubber. Learned this the hard way after tearing some o-rings on the pilot screws myself.

[robertbarr]

First, the washer reference was to the BS carbs. Yours of course are VM.

I'm going to presume you're talking about part 'A' here:

http://www.cycleorings.com/VMkit.html

Obviously, it has its own shoulder to handle the spring.

[I refuse to discuss any 'named' screw. Here's why: http://www.cycleorings.com/nomenclature ]

I pulled out my guinea pig VM body, which is equipped with the exact same O-rings I sent you. With a shot of silicone, I ran the screw down (lightly) to its limit and backed it out; repeated this three times, and examined the O-ring. It's fine.

I can't think of anything you could possibly do to harm this O-ring. Obviously something isn't right, or your O-rings wouldn't be destroyed; what that something might be is beyond me, especially on all four carbs.

(Even without lube, it shouldn't be a problem, but I still recommend a shot of silicone, or at least engine oil.)

So I can't answer your question. There's no reason I can think of why you'd have this trouble.

[Nessism]

(Even without lube, it shouldn't be a problem, but I still recommend a shot of silicone, or at least engine oil.)

I can confirm that the O-rings are easily damaged if they are not lubed up before installation. Small drop of silicone grease or oil helps immensely.

[greg78gs750]

ok, thanks guys, the whole washer thing had me in an unneccessary panic....i thought i stated these were vm's in the beginning, but i guess i didnt. im sure i overlooked the silicone, thanks again,

greg