Hello How are things? Good I hope.
I rebuilt carbs on 76 750F.
The Idle and off Idle to mid range works ok.
Open the throttle quickly and it hesitate and backfires, back off throttle and it goes ok with little power.
I ran down the highway at WOT 80 miles an hour and shut the engine off and coast to a rest area.
Pulled # 4 plug and it was plain white not anything at all. Pulled # 1 plug and found a little tan on a small part of the insulator.
This is what I check. I check for vacuum leaks. I check points and timing. I even took off the muffler to ensure that it was not blocked and causing back pressure. When I took it for a ride without the muffler you could really hear it backfire and break down and no power.
So I quess I must of missed something in rebuilding the carbs. I have the Needle in mid position and 120 jets.
Did I miss a port that I have to clean out?
I do not know the history of the engine and there may be something change inside.
Would Coils break down only on a higher rpm 5K .
The bike starts with Chock and Idles fine. You can rev it up and it will go back to Idle.
I wish I had other carbs to try.
Well I could remove the carbs and change the needle and jet, I could replace coils, wires , etc.
I guess I have to go with the plug result and change the color first.
Before the carb rebuild the Idle circuit system ran rich. Because of that the higher rpm breakdown was not as noticeable and the plugs were dark sout.
I went from one extreme to the other.
Well shoot me a thought.
Thanks
