high idle back fire, poping smokey exhaust out of right exhaust.

[ick]

my new vance and hines exhaust is now blue, the right two cylinders burn hotter.
carbs were jetted according to v and h specs but ran the same.
i went back to stock jets, u guessed it same issue!
oh, i forgot i also installed foam air filters which eliminated the airbox.
i dont know the history of this 82' 750F except i got it from folks that didnt have a clue!
i am told this model was good for faulty spark advancers can i test these for proper operation and then how bout cdi or pulse generator, thanks for listening

[woodsrider250-2]

Can swap coils and see what happens.  Fresh plugs?  Valves adjusted?

[ick]

thanks for the reply!
i've had the coils tested at a reputable harley/ suzuki dealer here in yakima wa tested ok.
the plugs i'll check but their fairly new. i havn't been able to ride this bike at all because of this issue.
even before i got the bike it ran the same w/stock exhaust but no bluing of pipes. carbs have been jetted
to vance and hines specs and then back to stock jets same result .the valves were
adjusted by a shop at least i paid for it! again i never have rode the bike or heard it run correctly, help!
i dont want to off it!

[ick]

thanks for the reply!
i've had the coils tested at a reputable harley/ suzuki dealer here in yakima wa tested ok.
the plugs i'll check but their fairly new. i havn't been able to ride this bike at all because of this issue.
even before i got the bike it ran the same w/stock exhaust but no bluing of pipes. carbs have been jetted
to vance and hines specs and then back to stock jets same result .the valves were
adjusted by a shop at least i paid for it! again i never have rode the bike or heard it run correctly, help!
i dont want to off it!

[CB750Winger]

  Just for the heck of it, take the plugs out and lay them on the head hooked to the coil wire and turn it over to see what the spark looks like. I put all new ignition parts in my 75 and it ran like crap. I check the plugs and one was dead. It was not the coil or wire, it was a bad new plug. Have you had the carbs off or cleaned? You can try running Seafoam in the gas to clean it up.   Paul

[Craig B]

I don't know if you solved your problem with backfiring yet, but over on the 750/900/1000 DOHC forum they are emphatic about the carbs on these bikes needing the stock air box and filter. Without the proper amount of back pressure provided by the stock airbox the bike will run way too lean, and re jetting to get a richer mixture just results in a poorly running bike.

Craig