I'm still in the middle of my cleaning/rebuild - too much to do on too many fronts, too little time. I haven't had a chance to work on the carbs for about 2 weeks now. Hopefully, this weekend I can squeeze some time in...
Anyway, as you've probably discovered by now, there are 5 different o-rings used in these carbs. Readily available o-rings are identified by a standardized sizing/numbering system that starts at -001 and goes up to ???. You can find the sizing chart, dimensions, and more than you really want to know about o-rings at
www.allorings.com. Most commonly available material for o-rings is buna-n (also known as nitrile). This material is fine for the carb application, fully compatible with gasoline. Viton is OK, too, but viton o-rings seem to cost about 3 times the cost of nitrile rings.
Although I haven't put any carbs back together yet, I've been measuring, looking for o-rings, sizing the 5 applications in our carbs. This is what I've determined so far:
"Choke assembly" - Size -011 seems to fit well.
Jet assembly - Size -009 seems to fit well.
Float bowl drain plug - Size -008 seems to fit well.
Pilot screw (the larger one)- Initially a size -006 seemed to fit OK; after getting some -005's, I find they are closer to the correct size, but neither is an exact match for the original (-005 is closer).
Air screw (the smaller one)- Size -005 looks like it will work here, too, but it also is not an exact match for the original, which is different than the pilot screw application, where a size -005 also seems to fit OK.
My terminology may be screwed up a bit; I don't have my Clymer in front of me now; I'm working from some scrawled notes and memory (becoming a higher risk situation as time goes by). If you have trouble sorting things out, let me know and I'll try to clarify it.
Where to get the o-rings? You may have some luck at a well-stocked hardware store. At the website listed above, you'll find a nice kit for only $10.00; if you're a real do-it-yourselfer, this is definitely the way to go. Problem is, it starts at size -006 and goes up from there. I have a friend involved in auto racing who has this kit in his shop, so that's where I was able to get the larger ones. Finding the -005s was tougher, though. Most sellers (websites, industrial supply houses, etc.) sell in lot sizes of 100, 300, etc.
I eventually found a local supply house from whom I was able to buy a pack of 100 -005s at a reasonable price. I gave some to my friend in exchange for the ones I took from his kit; I'll gladly send you (or anyone else, until I run out) the 8 I think you'll need, plus a spare or 2 if you'd like; just send me $1.00; that'll easily cover the o-rings and postage. Email me if you're interested, and I'll give you my address.