out of sycn?

after i rebuilt my carbs (dipped them, replaced the butterfly seals, wet set, and so on)

anyway, while i'm tuning it if i rip the throttle, it takes longer then i want for the rpms to fall, but heres the interesting part, if i push down on top of the 4th carb sync screw (to push the throttle back down after i pull it up) the rpm drops like a rock,
the return spring on the throttle is working, so its a bit weird.

i did vacuum sync with the yics eliminator in, it said they were synced

valves were done 4,000 miles ago by the previous owner, i'm going doing them anyway though, just want to get the bike running so i could see how much of a difference the valves made afterwards,

so i know thats a little confusing explanation, but what i guess i'm getting at is if the valves are out of spec

will the vacuum gauge read incorrectly, so you can't sycn them, (as in, even though all my vacuum gauges read the same, the carbs are still actually out of sycn)

or

will you not be able to get the vacuum gauges to all read the same, so that you know that they are out of sycn?

just curious about this.

 

If the valves aren't in spec, yes you can sync them (unless some are dead-tight) but once the valves are IN spec, you'll need to re-sync. The "carbs in sync with out of spec valves" configuration just won't have as much power as it will with everything in spec and in sync.

The fact that you can PUSH on the #4 carb's linkage and the revs will drop tells us you probably have a BIND in the rack that doesn't become an issue until everything gets hot.

You are probably going to need to pull the rack and re-align the carbs to each other. Then re-bench sync since that will screw up your sync. (Sorry.)

 

your right, of coarse it has to be binding a bit. cept maybe the shaft seals i put in need a little more time to wear in, or a little bit of grease, silicon grease on them right?

i'll bet it the seals, they were a little bit tight, and that would make perfect sense.

i'm not gonna pull the rack yet, but if the seals don't wear in and fix it, then i will

 

The throttle linkage return spring on that carb alone is way stronger than the seals' grip on the shaft. It's binding somewhere.

 

Try doing a sync without a yics tool, just for the sake of science

 

yup, it seems it has to be binding some where, the idle drops down quick when ridding, but not when im testing it in neutral in the driveway, doesn't matter though, i'll be breaking the rack again.

ima still wait till after i check the valves next week, and get them in check. i've never had a bike where the carbs fight me so much to go in and out, it sounds like that is normal for these bikes, but i also have a rebuilt 82 engine, in a 81 maxim frame, i couldn't tell for sure if the carbs were from the engine or the frame.