carbs surging

[ripinanroarin]

Well ,my carbs have been off, cleaned and set with a mercury vacume gauge. The bike seems to lop a little at idle " and adjusting lean mixture screws doesnt help". From 1000rpm to 3300 rpm it seems to run "un clean" like a small mild suge . And some times when I'm gearing down I burp the throttle and I get a POP.."hic" from one of the carbs. So I read the plugs and found 1 left rear and 1 right front cylinder with snow white plugs. Were to start now? Is this a common thing "running lean? do I jet or shim? Right off idle there seems to be a small flat spot as well. I'm sure this bike can run cleaner than this. :bang head:

 

[gamorg02]

how far out have you put your idle adjustments at?

if your idle is ok then maybe look at a shim under your needles.

 

[kaboom]

Well ,my carbs have been off, cleaned and set with a mercury vacume gauge. The bike seems to lop a little at idle " and adjusting lean mixture screws doesnt help". From 1000rpm to 3300 rpm it seems to run "un clean" like a small mild suge . And some times when I'm gearing down I burp the throttle and I get a POP.."hic" from one of the carbs. So I read the plugs and found 1 left rear and 1 right front cylinder with snow white plugs. Were to start now? Is this a common thing "running lean? do I jet or shim? Right off idle there seems to be a small flat spot as well. I'm sure this bike can run cleaner than this. :bang head:

I have the same EXACT symptoms.......I have not pulled my plugs to check them:confused2:

 

[gamorg02]

one quick test, put the choke on every so lightly. does it help? if so you know you need to go richer. i'd count a/f screws and try 1/4 turn out at a time on each to see if it helps, up to 3/4 turn or a full turn maybe. if that doesn't try shimming the needles.

 

[jfeagins]

Doesn't a slight lope @ idle indicate a rich mix? I always liked that effect.

I'm having the same symptoms, only very, very, mild. If I hold a steady throttle between 1500 and 2500 rpms, you can feel the bike surging as well as the occasional "cough". I was going to look deeper to see if I can locate any air leaks and go from there, but haven't had any wrench time lately. If mine isn't an air leak, I'm going to pull the slides to inspect inside.

 

[kaboom]

My bike is definitely rich......not horribly...... but definitely rich:confused2:

 

[ripinanroarin]

I feel much better now knowing this is a common problem with these bikes,..and that also means...some one has a cure!!! Yea,..tried the mixture screws ..zip. Well its time to hit the yamaha sights ect and find a cure for whats ailing old Max. I see Sean rebuilds these things and does an actual bike test with them.....hmmmm time to revisit his sight.

 

[06VMAXIMUS]

If all spark plugs are firing with good strong spark and none are wet, I would dig into the carbs. Tear the carbs all the way down and clean them good. Check/set float heights, then re-install with new fuel filter and see what you have then.

 

[tugla]

My bike is definitely rich......not horribly...... but definitely rich:confused2:

kyle so putting on the choke made it even richer? what are your screws turned out at?

 

[kaboom]

kyle so putting on the choke made it even richer? what are your screws turned out at?

They are stock untouched......the choke certainly richens it up