Topic: ‘72 Struggles Under 3k RPMs?

[SalNYC750]

fellas when sitting on da bike my 4/1 pipe doesn’t heat up on the far left hand side as fast as the other 3——-after about 10 minutes she warms up but struggles below 3k rpms and has faint black smoke when revved??? Anything over 3k rpms no problemo!!!!

Also exhaust is kinda stinky and there is a lingering fuel smell afta a long ride, she burns about a 1/2 qt. every 500 miles or so I think....

but pulls like a freight train?! strong like bull!!!!!

checked the bowls, gettin gas plus adjusted air and fuel screw —— head scratcher! 

[scottly]

Is da far left spark plug black as the Ace of spades? If yes, replace it with new. If it fouls again, youse have a problem wit dat carb.

[SalNYC750]

I’ll take a looky loo today 

[SalNYC750]

Looks good and normal! What next?!!

[Johnie]

Did you do a carb cleaning / rebuild and confirm float levels and sync? Are the stock jets in there? Besides the aftermarket exhaust any other things not stock like air box?

[HondaMan]

Check the clamps on the hoses that mount the carbs to the head.  If they are OEM, they are likely hard as a rock and the clamps might be loose, too.