Topic: RE: CB750 Stock Air Box K & N Running Lean?

[chewbacca5000]

I looked at the carb FAQ and saw, "Engine surges or "hunts" when cruising at part throttle" which matches my symptoms.  I have a stock air box and K & N filter I checked my plugs and they were lean at 1/4 and at 1/2 throttle.  1/2 out on the air screw seems to have given me a nice tan on the grounding strap of my plugs, but I am not sure what I need to do to get the nice tan at 1/2.  My grounding strap is white.  I think I am running 110 mains.  Would one clip position richer fix my problem?

Thanks!

[andrewk]

That's where I would start. (one notch higher on the needle clip)  How's it run wide open?

[chewbacca5000]

Not sure brand new engine, but more gas like 3/4 seems better.  With more gas it gets past the surging.

I am a little confused about the air screws is in richer or leaner? 

[chewbacca5000]

I pulled the carbs and at first they didn't look too bad, but after much reading of the carb chapter in Hondaman's book I decided to take a harder look.  Using steel guitar string I tried to see if the main jet passage was free and it appears to be partially blocked.  I probled and make progress, but am unsure if that is enough. I am pretty sure there are deposits in there too.

So I am thinking dunking in GUNK Carb cleaner 1 gal overnight might help things out.