You are here:

Motorcycle Repair/Honda CB350 four 1973

Advertisement


Question
I am restoring multiple Honda 350fours, but all have the same problem, mid range sputter around 5000 to 6500rpm range,then they power thru. Have used 3 different sets of carbs all rebuilt,one by wire george in TX.The ignition is pointless, valves are adjusted,new plugs,3 different motors. I have vac balanced the carbs.I just can't figure what is up. Can you shed any advice.  Thanks Tom

Answer
Tom, the bikes were jetted kind of lean from the factory. If you have changed the exhaust or intake systems, the bike should be rejetted, which may include raising the needles, by lowering the clip position on the needle.

Mid-range leanness is generally related to the needle taper/position.

The last few 350-400F bikes I have worked on responded to an increase in the main jet sizes from #75 to either #78 or #80.

Bill Silver

Motorcycle Repair

All Answers


Answers by Expert:


Ask Experts

Volunteer


Bill Silver

Expertise

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.

Experience

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.

Organizations
VJMC (Vintage Japanese Motorcycle Club) of North America

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

Education/Credentials
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.

©2016 About.com. All rights reserved.