Honda Twins banner

1 - 4 of 4 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 · (Edited)
Continuing on with my CB 350 project. Engine teardown is in progress. The top end is more or less in pieces and its time to decide what to do with the jugs.

I had the great fortune to have the cylinders measured up by our very helpful QC guy and his faro arm after work today. Both are right on the "replace if over" 64.1 mm mark in the shop manual. Taper and out of round are within spec.

I don't have the piston measurements in front of me, but if memory serves they're on the edge too.

Before going in to the project I was figuring on at least honing and new rings. So after this, would it be wise to go with a first-over bore job and new pistons altogether or will it suffice to hone, clean up the original pistons and go with new rings? I do have 2 shops within a half hours drive east or west and can get a full bore job for between $80 and $110 depending where I go.

EDIT: Just realized I fat fingered the 250 and 305 forum when I'm working on a CB 350. But in suppose the sa!me principles apply.
 

·
Premium Member
Joined
·
10,203 Posts
Moved it for you.

You need to determine the clearance between the piston and cylinder wall. Since your cylinders are at max you may have excessive clearance with worn pistons. If new pistons will bring this clearance within spec you could go that route. Some would say as long as you're buying new pistons anyway you may as well bore it 1st over and get "new" clearance. Depends on how deep you want to dive.
 

·
Premium Member
Joined
·
7,863 Posts
its a personal choice, but for me, any time I build a motor, anything even remotely questionable gets replaced. do the job once the right way or you may have to do again
my time is worth more to me than the price of questionable parts
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
Thanks guys. I like to tend toward the "do it right, do it once" mantra as well. But being as this is my first self-guided project I figured I would seek the wise counsel of hondatwins before doing something I might regret.

New first over pistons it is!
 
1 - 4 of 4 Posts
Top