1970 Honda CL350 Identifying Mystery Bits in Lower Crankcase

kimcheankoy

kimcheankoy

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Hi everyone,

I currently have my right crankcase cover off and discovered these metal and rubber bits at the bottom of the sump near the oil pump filter. There are fine shiny silver metal shavings that I cleaned out. I tried looking at parts diagrams but am having trouble figuring out where these pieces come from.

The picture with the large curved black pieces are rubber and the picture with small silver bits are metal that is magnetic.

Bike starts, runs, and shifts good around my property. It’s been sitting for a long time so this is my first time digging deep into it.

Any help appreciated!

IMG_0737.jpeg
IMG_0740.jpeg
 
You're looking at a top end rebuild to replace the part (timing chain / cam chain roller). Failure to do so is risk of further damage to the engine
 
Thanks for the identification! I’ll have to think hard about a top end rebuild.
 
This is what I found in my CL350 engine.
This is probably close to what the upper pulley on your cam chain tensioner looks like now.
71_CL350_62.jpg
Because the roller is disintegrating the cam chain can move side to side and chew up the tunnel resulting in the loose metal flakes you found in the oil.
71_CL350_63.jpg
You should strongly consider pulling the head and replacing the tensioner parts.
 
Last edited:
Cycleranger said:
This is what I found in my CL350 engine.
This is probably close to what the upper pulley on your cam chain tensioner looks like now.
View attachment 46919
Because the pulley is disintegrating the the cam chain can move side to side and chew up the tunnel resulting in the loose metal flakes you found in the oil.
View attachment 46920
You should strongly consider pulling the head and replacing the tensioner parts.
Click to expand...
Thanks for the visual. If it's inevitable, I will do the top end rebuild when it's not too hot. Did you only replace the rollers or did you replace the chain as well?
 
kimcheankoy said:
the picture with small silver bits are metal that is magnetic.
Click to expand...
The first piece looks like an oil control piston ring. Magnetic is steel not just aluminum from chain slap.
I'd say to split the cases and clean the crank and entire sump area. Cylinder walls should be checked too.
 
kimcheankoy said:
Thanks for the visual. If it's inevitable, I will do the top end rebuild when it's not too hot.
Click to expand...
I don't want to sound like doom and gloom, but with the amount and size of the rubber pieces in your first pic above I'd keep a close watch on it. If the cam chain sound changes significantly one day it could mean bigger chunks might have come off the tensioner roller and if you continue to ride it there's a greater potential for the loose chain to jump a tooth or two, and if that happens while you're riding it could become a lot more expensive in a hurry.
 
I just looked at the oil filter and it’s pretty bad with the amount of metal in the filter.

I’ve decided I will tear the engine down to see how bad things are, but I’m ready to cut my losses and make it a parts bike since I’m not wanting to spend a fortune on this.

IMG_0868.jpeg
 
Wow, yeah that hasn't been cleaned out in a looong time, if ever!
The cam tunnel on my head was pretty chewed up but I didn't find anything close to that in the engine.
 
That's the first place I look.
If non-magnetic, then aluminum and the crank may survive, it will need cleaned but it's better than rust.
Next question is the piston bores and that is a money question. Sometimes you can skip a bit on the valves, it depends. The worn groves in the cam chain tunnel don't matter much if not worn through.
Buying a used motor could be the same or worse, it's a gamble.
 
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