Is this Toast?

Update: after 1 hour I can still feel a bit of a lip above the block on the left cylinder. Right feels good though. Gonna leave it at temp over lunch and check around 1.

Update 2: it feels a little better after cooling off, but there’s definitely still a bit if height difference. Any chance this will get sorted out when I torque down the head? If not I’ll heat and separate them, clean both, then try again.

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Separated them again and really cleaned out both, still not sitting flush, so I figure this is as low as they’re gonna sit. I’ll take them to a machine shop to get it flattened and the cylinders cleaned up. Bottom end of the motor is together so really just need to get this sorted to finish the motor build.


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So I finally played with the 350 engine again tonight. Long story, but a new project has been getting all my attention. Cleaning out the oil pump to continue engine assembly and cracked the holder for the screen taking it off. Any problems running it as is or should I go find a new one?
 

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Before you waste anytime pulling bearings, make sure you can get new ones.

XS650 crank bearings for example are difficult to find, at least one of them if memory serves. Like they don’t make them kind of hard.
If I remember right, the 'hard to find' bearing isn't that difficult to get but is crazy expensive. 3 bearings are about $50.00 each, the other $100+?
GS850 piston is 360 only, unless you split crank and fit different connecting rods for the larger piston pin (very expensive, probably won't get any change from $450~$500)
It may be too late now but if the top flange of liner is sticking up slightly, you need to press it down. The differential expansion makes the block 'shrink' further than the liner.I found this out the hard way when I did my XS'800' Honda liners are generally 'loose fit' only around 0.00!5" larger than the hole they fit in. Normal fitting size would be around 0.003" larger
BTW, I like toast, you can eat it raw or cooked :rolleyes:
 
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It may be too late now but if the top flange of liner is sticking up slightly, you need to press it down. The differential expansion makes the block 'shrink' further than the liner.I found this out the hard way when I did my XS'800' Honda liners are generally 'loose fit' only around 0.00!5" larger than the hole they fit in. Normal fitting size would be around 0.003" larger
BTW, I like toast, you can eat it raw or cooked :rolleyes:

Not too late, I’ve been dragging my feet and haven’t sent the cylinders out yet. When I spoke to the shop on the phone they said cylinders shouldn’t stick out if I’m swapping barrels, so they’ll take a look at it and correct if necessary.

If it’s raw is it still toast or just bread?
 
It's easier to just clamp it down and warm it up to about 350f. Couple of long bolts, flat bars and some metal tube over spigot. I was swapping liners on so many XS650's at one time I made a custom clamping jig.
 
CrazyPJ is correct. Those liners need to be pushed back down. If they are left slightly high and then ground down, they will drop in use when the motor gets hot. And then the gasket will probably fail.

Easiest way is with a press and a flat, thick piece of metal to spread the load.

If your shop can heat the barrels and press the liners down and hold them until it's all cool again, that would be good.
 
I'll call the shop back and double check. I know swapping barrels is one of their advertised services and when I mentioned my problem the person on the phone said it shouldn't need machining and they'd check for me. Assuming/hoping they have a way to heat/hold/cool, but if not I can get out some clamps and flat bar then toss it in the oven at work.
I'm thinking just the big hunk of steel I used before with some unistrut above and below the cylinders bolted together (we have a bunch of small unistrut chunks laying around at work).
 
Mega thread revival… got another project so the 350 stalled out. Trying to wrap up the engine build now and keep running in to hurdles. Machine shop said pistons were out of round and required going to +1mm, got everything back and went to assemble last night. Noticed my cam chain tensioner does not look like any drawings/pics of the 350 roller and doesn’t fit in the block opening. Also looks like the cam chain I got in the parts lot years ago is too short… so thinking about getting the KA slipper and a master link chain so I don’t have to split the cases again. Thoughts?? Also any clue what this tensioner is?
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Ended up ordering the proper chain and tensioner. Motor is together, but came across an issue when trying to set ignition timing. The engine is not smooth to turn over. There are points where it’ll jump forward, one of which is right around the LF/LT marks which is making timing it a pain. Any ideas why this is happening?
 

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If it's jumping forward I'm guessing it's because a valve is pushing on the camshaft. (As in it's normal)
 
Mega thread revival… got another project so the 350 stalled out. Trying to wrap up the engine build now and keep running in to hurdles. Machine shop said pistons were out of round .....
Eh?
Pistons are supposed to be out of round. They are cam ground so that there is more clearance side to side than back to front. That gives the right clearances as it runs on the thrust faces and the extra side clearance is to reduce viscous drag. Pistons may be round at the crown or in the ring lands but not the skirts.

And pistons are also tapered. Largest at the bottom and smallest at the top so that when they expand when running, they are more or less the same diameter.

Modern pistons (ie for modern engines) are much shorter and often have no "sides" and they are what used to be called "slipper Pistons". less reciprocating mass and reduced friction are the way to more performance and that's why some of us shorten our race pistons and take more metal off the sides and have to replace them more often.
 
Eh?
Pistons are supposed to be out of round. They are cam ground so that there is more clearance side to side than back to front. That gives the right clearances as it runs on the thrust faces and the extra side clearance is to reduce viscous drag. Pistons may be round at the crown or in the ring lands but not the skirts.

And pistons are also tapered. Largest at the bottom and smallest at the top so that when they expand when running, they are more or less the same diameter.

Modern pistons (ie for modern engines) are much shorter and often have no "sides" and they are what used to be called "slipper Pistons". less reciprocating mass and reduced friction are the way to more performance and that's why some of us shorten our race pistons and take more metal off the sides and have to replace them more often.

Whoops, my bad. Wrote that post late, it was the cylinders not the pistons. Doh!
Thanks for the info though, I had no idea that was the case with pistons.
 
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