You are here:

Motorcycle Repair/1971 CB Honda 750

Advertisement


Question
My beloved 71 CB 750 is spurting oil after turnoff from around the back of the motor.The 2 lower fins at the left front of the motor will show a drop of oil haging as well .The head and base gaskets don't appear overly saturated.I've tried to pin it down when I shut off the motor by looking but it's subtle and a little stream comes down the channel at the base of the cylinders  on the left side of the motor and runs down the side covers.The cam chain tensioner gasket appears to be really saturated and I figure that may be the problem. Do I have to pull the motor to replace it or is there some sealer that might get me by ?The bike runs great and has 75 000 miles on it.   Many Thanks

Answer
Ted, The camchain tensioner just unbolts off the back of the cylinder block.

http://www.cmsnl.com/honda-cb750-four-k3-usa_model481/partslist/E++06.html#resul

My initial suspicion is that the camchain wasn't kept properly tensioned throughout its life or it is just flat wornout/stretched and is carving its way through the cylinder block and now has ventilated the engine.

After 42 years and 75k miles, it is time to go through the motor and freshen things up inside. This will not be cheap or easy, unfortunately, and the motor has to come out of the frame for any serious work. It weighs about 175 lbs, so get help with the R&R.

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.