So I've inherited a couple bikes from my dad (read:they've been sitting in the garage and I want to get them to run so they're not taking up space). For some reason, he has a complete 360 engine that looks pretty much brand new and has .5 over pistons and I was wondering how they'd work in a cb350. I know the wrist pin is bigger (16mm for 360 and 15mm for 350 if I'm not mistaken) but other than that, how would the compression and skirt length and what not work with a 350.
CB360 Pistons in a CB350
- Thread starter kbaszak
- Start date
crazypj
Split personality, I fake being smart
I don't think it works.
I looked at it about 7~10 yrs ago, can't remember much about it but it was more trouble than it's worth. (and I do some weird stuff ;D )
360 motor doesn't fit 350 frame without some major cutting and welding either
You would be better off either finding a titled 360 frame or just building 350 motor
I looked at it about 7~10 yrs ago, can't remember much about it but it was more trouble than it's worth. (and I do some weird stuff ;D )
360 motor doesn't fit 350 frame without some major cutting and welding either
You would be better off either finding a titled 360 frame or just building 350 motor
rockcitycafe
I make things.
wrist pin is for sure different, and I think the 350 pistons are taller (longer distance from wrist pin to dome)... pj's right, just find a 350 engine, they're all over the place
Sorry, first post was confusing. I just bought a 350 engine but the walls are toast and it needs to be bored out. My dad had a set of some really nice .5 over 360 pistons but I have no other pistons for a 350. One of my dads really good friends is a engine machining instructor at pretty well known automotive school so the engine work would be free.
Sorry for the pretty poorly worded first post, guys.
Sorry for the pretty poorly worded first post, guys.
1969Honda
Been Around the Block
Give me a few hours until I get to the garage to change out the tranny in my metro and I'll post some pics with all the measurements for a CB350 stock piston. I still have mine as they were not in bad shape, but figured I would bore it out vs honing and new rings to get a slight (very slight) increase in output.
rockcitycafe
I make things.
the cb350 and cb360 have different wrist pin diameters. unless you've got a pretty good machining setup, probably including surface grinders and a few thousand in associated fixtures, it's not something you can overcome in your garage. cb350 os pistons and rings are on ebay for really cheap
I know someone who teaches a machining class at a pretty well known automotive school so machining cost isn't a problem. So it's either cost of wrist pins or cost of pistons. I haven't really looked at which would be cheaper but I can't imagine wrist pins being more expensive than pistons.
rockcitycafe
I make things.
so what's your procedure for fitting a piston with a 16mm pin into a con rod with a 15mm hole? because from my comparatively limited machining experience, that sounds like a rather involved job
crazypj
Split personality, I fake being smart
Roc City Cafe said:
It's actually pretty simple to make some sleeves to fit over stock pins.
They must have an internal lip to prevent 'small' pins sliding out and chamfered for circlips.
Hardest part is making everything accurate enough.
I've use same method in several motors
It's much safer than grinding out small end
rockcitycafe
I make things.
do the sleeves move against the pistons or do the pins move against the sleeves? seems if the sleeves moved against the pins, you'd have to factor in some method for keeping them aligned with the oiling holes
What's the danger in putting the rod on bridgeport with a boring bar and boring it out to 16mm? But now that I've noticed the 360 pistons are quite a bit shorter I'm thinking about just selling them and getting 350 pistons. I'm a pretty broke college student so I was trying to save money where I could on this but I think the lack of compression would be pretty significant.
crazypj
Split personality, I fake being smart
First off, you have to completely strip crank to get rod off it. (it's not like an automotive crank/rod)
There is also the (pretty good) chance that the small end will become weak enough to come apart
0.5mm all round doesn't sound much, but, the rods are build to take the stress of normal piston, not a slightly heavier one with less material in small end
There is also the (pretty good) chance that the small end will become weak enough to come apart
0.5mm all round doesn't sound much, but, the rods are build to take the stress of normal piston, not a slightly heavier one with less material in small end
rockcitycafe
I make things.
pretty sure the bearing surface of the small end is hardened then honed to size, not really something you'd do exclusively on a bridgeport
