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Motorcycle Repair/1972 cb450 carb and timing issues


My name is jake winters I am having trouble with the carbs and the timing.  Please help thank you

Jake, that is a very open-ended question, with little info for me to work with.... Here are the basics....

You need a fully-charged battery for the ignition system to work properly.

Set point gaps so they are at a maximum gap of .016", then move the point plate around until the left side opens at the LF mark, then check the right side and if the timing is not matching the left side, then adjust the point gap slightly until the right side points just open at the F mark.

Carburetors have various calibration codes, stamped on the carb bodies around the inlets. The code stamped will match a set of jets that are required for a particular model. CB450 carbs are jetted differently than the CL450 units.

Without knowing the carburetor code I can't say what the settings are supposed to be for your bike.

If you have altered the exhaust system and/or the intake system (mufflers and air filters) then the stock settings for the carburetors will probably not work. If that is the case, then stock up on main jets and primary main jets and perhaps even idle jets and start to experiment with what works best.

Before you start, make sure that your valves are adjusted properly and the compression is up around 160-175 psi on each side. Low compression, inaccurate ignition timing and air leaks at the intake manifolds and/or exhaust joint connections can all cause performance issues.

Bill Silver

Motorcycle Repair

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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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