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Motorcycle Repair/Vent Hole Termination


QUESTION: I have a CB77 305 - 1966 and the carb slides stick unless the carbs are loosened to the point that they have a vacume leak.  Is there a fix for this?  I have a couple sets of CL77 carbs, could I try those slides for fitment or are they different.  Thanks.

ANSWER: David, the carb bodies are basically the same for CB and CL models, so you can interchange parts, other than the jetting.

File the flanges flat, replace the o-rings with the 260-004 code parts (not PF0-000) in carb bodies and insulators. With carb bodies off the bike, run the slides up and  down inside the bodies to establish where the wear pattern is taking place then use some emery cloth to work down the high spots. Test and repeat the process until the slides will drop down by their own weight.

The coated alloy slides are less likely to stick then the early chromed brass slides.

Bill Silver

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QUESTION: Where should the two vent holes near intake & the one on top of the motor go to?  I have tubing for them but where/how should I end the run?

David, the top vent tube is the crankcase breather tube and should run down the back side of the motor, left of center, into the little slot in the top transmission cover and then turn 90 degrees and lay down with the end pointed towards the drain hole in the crankcase valley.

The two intake vent fitting tubes can just hang in space. They originally connected with a Y fitting and then hooked up to a small fitting on the air filter. They do not have manifold vacuum on them, so are basically just a vent hose.

Bill Silver

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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