Gurus - another 1000 carb synch question

[dontwantapickle]

Ok, my project engine - 76 GL1000
Not stock
No airbox
K&N filter
open pipes
etc.

I hooked up the synch gauges this morning and began tweaking.
At idle (980 rpm.) the synch gauges are dead on.
at 3000 rpm. #1 and #4 are about an inch off.

If I synch the carbs to equal at 3000 rpm. the bike seems to maybe smooth out a bit
but... when I drop back to idle, the gauges obviously read off
but... the bike still idles really well, no throttle hang, starts easily, ect..

What gives?
sticky slides?
slide spring rates different?
worn out gauges?

I think I'm gonna leave it synched at 3000 for now and see what happens.
Any ideas?
has anyone ever even ran their bike up to 3K with the gauges hooked up and
noticed a change in vacuum ?

[Chris in TN]

I can't speak for everyone obviously but I always synch any motorcycle at running RPM rather than idle since that's where the engine will be operating. Normally that means there will be fairly minor variances at idle.

[tlbranth]

Even though I've spent 2/3 of my life screwing with GL carbs, I don't remember what all is adjustable. But 3 things come to mind: The little flap doohickeys that the throttle controls are not opening in unison (don't remember if the linkage can be adjusted for this), the slides are not rising uniformly, or you have vacuum leaks.

[dontwantapickle]

"The little flap doohickeys"
Thank's for the laugh, definitely not the guru like reply that I was expecting.

[pidjones]

With all of the changes that you listed, I couldn't even guess at your problem. Except, the straight pipes probably don't effect it. When you enter unexplored territory, you should do so one step at a time, not jump into the middle of the jungle!