Mixture Fixture 2

[tbishop11]

So today I attempted a Sync / Mixture adjustment and its better then it was the carbs are pretty close to being synced and the mixture is close too but I've encountered another problem.
When I rev the bike after a couple revs it revs up by its self and keeps revving until i rev it real fast a few times and then it drops back down. It's weird and frustrating! The linkage isn't sticking any where it seems internal within the Carbs?
Please once again I'm at a loss?

[MindWebs]

slides?

it sounds like you may have a leak or 2 in your rubber diaphrams on the carb slides.
check them with a flashlight and make sure there are no pin holes in'em

is there is fix with light coat of silicone.
there is also a write-up in the tech tips i believe...

but it sounds like your slides are not droping correctly at either rate.

polish your slides to ensure there is no varnish(gas) build up on them that
may be causing them to "stick". 1 or 2 slides sticking would be enought to
play havoc with your bike returning to idle.

[boyat68]

It still seems as if you have not synched quite well enough. The hanging RPMs is an indication that one or more carbs are pulling more than the others. Once you have all of the carbs pulling at the same hg. and the idle set, the bike will respond quite well. I know that it is a hair puller, but keep synching to the point that all of the carbs read very near equality. Check your plugs often to see that they all are firing and clean.

[tbishop11]

The slides and diaphrams are good, and they were synced up pretty good but I'll check both the slides and the sync again though because who knows at this point. Maybe one of the backfires yesterday blew out one of the diaphrams? Its making me crazy

[DiverRay]

If the hang up is AFTER you have the sync tool removed, check the vacuum plugs on the carb holders. If you can spin them, they are bad, and causing a leak. I use some vacuum line with a stainless steel cap screw in the end. Not quite as pretty as stock, but it works.

[tbishop11]

That is a very good possibility I'm on my third set of Vacuum plugs and I think these are probably bad, in fact now that you mention it, it back fired yesterday and shot one across the shop.

[thewiz]

I think ...

it's possible that one or two float levels that are too high could contribute to that slow return to idle as well.

[tbishop11]

They were all good too, I would say this is more of a take off by itself rather then a slow return it's weird?

[thewiz]

Ya' know, tb ...

Planedick had an F that did exactly that which he later sold to the Diver. Now Planedick, clever man that he is , stuck a spring onto the vac advance plate somewhere and that stopped it. You might ask the Diver what he found was wrong .. cuz I think he fixed that issue once he got it home.

BTW your vac advance hose is on the #2 carb port, right, and not the manifold? Have you tried pinching off the vac advance hose to see if that stops it? The advance plate itself can also become sticky over time, so you might check that it moves back and forth very easily. Also,I have seen the the mechanical advance weight and spring governer unit on the crank snout stick in an advanced position .... just a few more things to check out

[tbishop11]

Just got done pulling it apart and the #4 carbs float was full of gas among other things the vacuum slides were good but I think that is my main issue for know. I've about had it with these carbs, I've worked on a lot of bikes and these carbs are definitely the most finicky! I'm about to give Flea bay a try? So long story short looks like every body was right about one thing or another.

[81xsproject]

These carbs are VERY forgiving. Fix the float and start over. Now that you have a properly equipped set of carbs, NOW you can tune them. You can't blame the carbs for you not testing your floats for leaks.

ps If you want to pay the price for "bolt on and ride," I am going to sell my prized set because the FI is going so well. PM me if you're interested.

[foreda]

Finicky Carbs

Just got done pulling it apart and the #4 carbs float was full of gas among other things the vacuum slides were good but I think that is my main issue for know. I've about had it with these carbs, I've worked on a lot of bikes and these carbs are definitely the most finicky! I'm about to give Flea bay a try? So long story short looks like every body was right about one thing or another.

One must remember these carbs are 30+ years old. Older than a lot of folks here (excluding me). If you need a float, I have a couple laying around. Don't give up, you won't regret it once you get it running right!!

[tbishop11]

One of my main problems is that I have two of my float posts broken on the same carb and now I'm on my third super small crack on the same float its just so thin that it forms a new crack after about a week of just sitting. This is definitely not my first carb rebuild but its making me feel like it. I really do appreciate all the help and support. Thanks everybody. Even if I never get to really take her out on a good ride at least I know that I have had great support here.
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