idle/backfire issues

i have an 81 kz750 h2... i'm having a problem with my idle... SOMETIMES it wants to run high (3000 rpm+) and it usually comes after running the engine high accelerating... i noticed that if i push down on the carb unit (filter side) the idle returns to normal (1000-1250 rpm)... i think i need new carb holders but.... not quite sure... i've put seafoam in my tank (1/3 can... been in for about a week) and have removed my filters and sprayed some carb cleaner in them...

also i've been getting backfires out of carbs 3 and 4... donno if this has anything to do with it..

tips/suggestions???

thanks!

Have you checked the input voltage to the ignition coils? It should be the same as battery voltage. If it is a lot less, you might consider doing the "Wired George" ignition relay bypass modification. His website www.wgcarbs.com lists parts and how to do it.

i would start with the vaccum lines with a small leak the idle will be eratic and rev up and cause a lean condition wich may explain the poping or back fire in the exhust might be a cheap fix and were id start

is that the same repair for backfiring through the exhaust and flames? should I look for a leak in the vacuum lines? can't find any vacuum lines to look at?? the engine is a 77 KZ1000.

it sounds like you need to replace yor intake manifolds air leaks will cause erratic idles and it will cause the engine to not return to idle properly. the backfire is caused by a lean mixture which is a symptom of leaking intakes