Cb360 piston rusted and stuck in cylinder

stubsryan

Been Around the Block
Picked up an old cb360 and it wouldn't turn over. So I pulled the engine out and took the head off. Wow it's really stuffed. Now I'm trying to get the cylinder block off for machining and the piston is super stuck. Soaked it in oil for a few days after cleaning to no avail. Just tried heat, rubber mallet and even a hammer on the piston. Won't budge. Any ideas?
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My suggestion would be to pour some diesel on there and torch the cylinders until the diesel starts boiling, then use a BIG hammer and a block of wood on the piston..
 
So it looks like sand but I think it's actually corrosion. Must have got a crap load of water in there at some stage?!

What's ATF?

Thanks for the help!


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Chances are good that if the cylinders are that bad, the bottom end is in rough shape as well. You'll likely need new bearings and at least a very thorough rebuild.
 
Those chambers are toast. I don't think the head is usable anymore. Did that motor sit without carbs or something? Good chance the whole damn thing was full of water.
 
SONIC. said:
Chances are good that if the cylinders are that bad, the bottom end is in rough shape as well. You'll likely need new bearings and at least a very thorough rebuild.

Surprisingly, the corrosion in cylinders often 'protects' lower end of motor from further damage. May be a little rust on edge of flywheel but all the bearings, crank and transmission should be good. Don't scrap block, it's ideal candidate for 378cc conversion or liner replacement (plenty of people have similar damaged blocks, make 1 good from 2 'bad' use damaged liners for 378 motor)
Pull valves out of head, if seats ain't too rusty to be re-cut it will clean up OK. If cam bearings are good it's worth salvaging even if it needs a new valve seat fitted
 
Awesome advice guys! So a whole lot of effort later I got the cylinders off. Man that was difficult what it is.


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So I have been looking for a replacement engine. I can't find a cb360 engine at all in Australia. Even the motorcycle wreckers don't even have them. Maybe the 360 was a limited release in Aus. Thought about fitting a cb350 twin but again they are rare. One guy wanted $1000. It's annoying because on eBay there is a cb360 engine complete for $275 but it's in America! I'm going to try and fix this one up. So another issue is a spark plug broke in the head. I thought oh ok I will use an easy out. Well that snapped off in the plug! Damn it! I will get it but damn that's annoying


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Easyouts SUCK.
The only time they work, you didn't need it anyway.
I've always found the wedging action forces tin sections even tighter into 'whatever'
Get a small punch and drift out plug centre then use a 7/16"drill (all from combustion chamber side.)
As for fixing up engine, not a problem as everything below piston looks good.
Even if you do have to get a pair of valves it will probably still be way cheaper than a full engine shipped from USA (shipping may be more than cost of motor?)
Either get a cylinder block and piston set or just have it bored for Suzuki GS850 pistons (69mm)
You may have some luck getting Suzuki pistons in Oz as they were way more popular than CB360's
I know Suzuki had 0.50mm oversize pistons available a few years ago but stock have not been available from Suzuki since 2010. Plenty of people with no experience have done 360 motors so you shouldn't have many real issues
 
crazypj said:
Easyouts SUCK.
The only time they work, you didn't need it anyway.
I've always found the wedging action forces tin sections even tighter into 'whatever'
Get a small punch and drift out plug centre then use a 7/16"drill (all from combustion chamber side.)
As for fixing up engine, not a problem as everything below piston looks good.
Even if you do have to get a pair of valves it will probably still be way cheaper than a full engine shipped from USA (shipping may be more than cost of motor?)
Either get a cylinder block and piston set or just have it bored for Suzuki GS850 pistons (69mm)
You may have some luck getting Suzuki pistons in Oz as they were way more popular than CB360's
I know Suzuki had 0.50mm oversize pistons available a few years ago but stock have not been available from Suzuki since 2010. Plenty of people with no experience have done 360 motors so you shouldn't have many real issues
Thanks mate. I'm going to take the valves out and then decide what I should do. If they are ok then I will fix the stuck spark plug and move on to new pistons etc. worst case I can get a new second hand head with valves for $160 or so. The cylinders need boaring and new pistons with rings anyway so maybe the 69mm pistons will work well. Can't remember what I have at the moment, the bore size was 67 maybe? Anyway, will sort that out later. I have two projects on the go at the moment, got a Cb350f so funds are spread thin over two builds! Thanks for the advice


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Back in 'the good old days, we had to re-profile masonry drill bits to cut through high carbon steel. Easyouts ain't too bad to fix, snapped taps are much harder as they are tool steel. Taday, things are 'easy', get diamond coated burrs and 'Dremel' through just about anything ;)
 
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