Understanding the Keihin PW22?

[DianneB]

Before I overhauled the engine on my '67 Dream, I had it running twice and it idled pretty good - never did try to take it on the road. The compression was TERRIBLE. On the second run, it ran long enough to warm up and the rings stuck so I did an overhaul with carb kit, new rings, gaskets, seals, etc., and converted to Probe electronic ignition.

Initially (after the overhaul) the engine was running terribly rich, "slobbering rich". I got 1/2 mile down the road before it drowned and wouldn't restart. It left a puddle of raw gas under the left exhaust and fouled the plugs something terrible.

I took the carb off again and checked all the jets - all the right size - and made sure all the passageways were open - they were. I dropped the needle from the 3rd ring to the top ring with a very small improvement and finally did some modifications to the main jet mounting body to raise the main jet in an attempt to further lean the mixture - that helped a great deal and it now runs but it still isn't right (NOT a modification I would recommend to the faint of heart LOL!)

There is SOMETHING wrong with this carburetor that I haven't found yet and it has me stumped! I have no idea what "backyard modifications" may have been made to it before I got it but there were screwdriver dents on the bottom of the slide as if someone had tried to pry the slide up at some point. I checked the jet sizes and they are close to book values so I am completely puzzled as to why it is still running extremely rich. It does start to improve at high throttle settings so it is something wrong before the 1/2 throttle point.

Has anyone found a detailed description of the workings of the Keihin PW22 carburetor, something that would help me diagnose the main "fuel paths"?

Thanks gang!

[R100]

Factory Service Manual.

[DianneB]

Factory Service Manual.

Is there a factory service manual for the carb? The Honda service manual doesn't go into details about the inner workings of the carb.

[R100]

This is the manual I have from E-Bay.
Tried pics of the carb description pages, hope they will be readable.
(Watch out for any differences between PW22 and PW26.)

[R100]

P.S. The shop manual on Bill Silvers CD appears to be the same.

[DianneB]

Thanks man, that helps!