Topic: 1972 Honda 350 Four: 30,000 miles? What do I need to do on the engine?

[twincityrider]

Hi All,

New to the forum and glad to be apart of it.  Lots of great info here.  I have a 1972 Honda 350 four that I picked up for $375.  I'm doing a full restoration on it (minus major engine work if I don't have to).  Bike ran rough before I completely tore it down.  Carb work is needed.  The bike has 30,000 glorious miles on it.  It's currently at the powder-coater getting a makeover.  My question is when do these bikes need major engine overhaul?  When does the top end need to be redone?  Bottom end, etc?  I took the valve cover off and everything looks good however the rocker arms are showing slight wear.  Also cylinder 1 exhaust port seems pretty clogged up with soot.  Can I remove that externally and call it done?  Thanks.  I'm looking forward to being apart of this community.  Will post pictures soon.

-TwinCityRider

[HondaMan]

Hi All,

New to the forum and glad to be apart of it.  Lots of great info here.  I have a 1972 Honda 350 four that I picked up for $375.  I'm doing a full restoration on it (minus major engine work if I don't have to).  Bike ran rough before I completely tore it down.  Carb work is needed.  The bike has 30,000 glorious miles on it.  It's currently at the powder-coater getting a makeover.  My question is when do these bikes need major engine overhaul?  When does the top end need to be redone?  Bottom end, etc?  I took the valve cover off and everything looks good however the rocker arms are showing slight wear.  Also cylinder 1 exhaust port seems pretty clogged up with soot.  Can I remove that externally and call it done?  Thanks.  I'm looking forward to being apart of this community.  Will post pictures soon.

-TwinCityRider

Take a compression check (with throttles full open), then add a teaspoon of oil to each cylinder, and take another check. The later number should come up by 10 PSI or more if the valves are good. The number itself should be between 90-110 PSI.

If the number does not come up at the second check, the valves are leaking.
If the number is low, like 70-80 PSI, the rings are leaking.

The little bores are pretty simple!

[markjenn]

Compression test would be good to do, but I'd clean up the carbs (and make sure your tank isn't rusty), give it a complete tune-up (points, plugs, condensors, valve adjust, cam chain tensioner adjust, new air filter) and see how it goes.  If the thing will run 85+ mph indicated, it's doing Okay.

- Mark

[HondaMan]

An observation (hopefully I don't sound like a salesman here, as I'm really NOT trying to nudge another sale, I'm busy enough...):

Loonymoon said the addition of one of my Ignitions made her 350F start at the touch of the button, and wind up more than she cared to ride it. As much as these Baby Fours love to spin, I would think that the points alone would have their hands full. I remember when I used to work on them: after a tuneup, they were like a sewing machine and would run nearly 100 MPH with me sitting straight up: 3000 miles later they were 85 MPH bikes.

There's a neighbor here with a beautiful supercharged '55 Chevy and a brand-new (from all appearances) green CB350F in his garage. He never rides the Four, but buzzes around sometimes in the summers in his Chevy. Some day....drool...