1978 CB750A Fuel Problem?

Posted by Jabulani on
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/1978-CB750A-Fuel-Problem-tp460680.html

Hello fellow CB750 enthusiast,

  I recently pulled my dads 1978 CB750A out of the garage after being let sit for 10 years.  I was lucky that he drained the gas tank and carbs before he stored it.  I did end up pulling the carbs off and soaking/cleaning them anyways just to make sure.  Everything went back on the bike great (new spark plugs, oil change/filter, and air filter.)  Had the carbs synced and runs fairly well in first gear except when its cold.  Second gear is pretty good between 35-50 and then at 55-65 the engine begins to sputter and run like junk.  If I throttle it continues to sputter until about 68-70 and then it catches again and tries to almost lift the front tire off the ground.  It continues to have good power all the way until about 80 (scared to do much above that at this point in time).

  What would make it only sputter intermittently between 55-65 mph?  I am currently getting 28 mpg and I think it has to do some with my hwy driving is about 60 mph and it doesn't run very well at that speed.  Does anyone else have problems like this?  Anyone know of any causes for this / possible solutions?  I have gotten rid of my car insurance and have the bike for the summer.  It runs reliably at this point, but kind of hoping on taking it on a few longer rides and want to get better gas mileage than 28.  My honda civic gets 39-42 hwy but I can't afford the insurance on it right now so thus the motorcycle.

Thanks in advance,
Stephen