Well, Cam Chain is broken...

cleoncleon

cleoncleon

Been Around the Block
Long story short, I got to try out some new jets today, a 150: Main and 25:pilot on my CL360, working realll nice, but.
As i pull into my garage I hear this rattle, so i stop reving at let it idle... Then a few moments later i hear a huge PING and hte motor shuts off...
Turns out one bolt on the cam sprocket got loose then all that happened... Chain broke, found the bolt, slightly chewed by the chain. So Im assuming i have to break
the case and get the rest of the chain bits out.

Any tips, will i need any special tools or go through any special procedure to get a new cam chain on?
 
You may need the peg spanner to remove centrifugal filter nut (it's possible to get the crank out, but much easier with filter off)
I pull the generator rotor, mainly to save some weight when rebuilding, couple of pins need to be lined up in top case with main bearings
I use a 10mm quarter inch drive deep socket with long extension plus Loctite on the cam sprocket bolts.
I don't think it's possible to over tighten them that way, plus, deep socket prevents cam turning when it touches head so you can actually tighten bolts
Are the tensioner and guide OK?
 
Tensioner and guides look good!
Luckily this breakage happened at idle, so, no too much went flying off, i herd the snap, which was the chain, then it cut off.
I took the bottom case off and cleaned it, my oil filter was actually quite clogged, so i cleaned that off aswell.

Right now the cases are apart, and besides the chain not on yet, all seems ready to bolt back up.
I managed to get the bottom half off with the centrifugal filter/ Magneto/ clutch basket all still on.
It looks like I can lift the cranks up on the filter side a bit and shimmy the chain onto the bottom sprocket. Don't need to take anything off ;D , or will I?
I did see those two notches where the bearings sit, I'll make sure theyre in when Im bolting stuff up.

As for reassembly, I didn't see where the shifter arm came off of, it just sits in place, but i didn't see where, since the engine was upside down when i got the bottom case off.
And as for the bottom case bolts, when putting them back in, could i apply some hightemp grease to the threads for easy removal next time?
Tobiism, seemed to have done this, and it made for an easy disassembly, so I would like to do the same. Just not sure if he used liquid gasket or grease... :-\

Blue loctite fine? or that devilish red...
 
PJ,
Is it possible for a piston to smack a valve and bend it when this happens? If so, valve integrity needs to be checked.
 
Yes, valves need checking, it's highly likely that at least one valve is bent.
Check the guides as well, they can get cracked when valves bend.
You have complete top end disassembled?
Crank has to come up high enough to get chain past rod.
If you split and re-rivet chain you can just drop it through from bottom (case upside down)
CB750 chain has to be shortened so you will have to split it (or are you using a stock 360 chain?)
 
Thanks for clarifying that PJ. I thought that maybe he had a risk of a bent valve, but I am not as familiar with that engine as you are. (Few people on the planet are!)
 
shitttttt. shit. Bent valves??
Would I feeler gauge those?
Could a bent valve still happen when at the time of the break I wasn't moving, nor was the engine moving fast?
I feel like my damage shouldn't bet that monumental, but i'm hoping for the worst now...
I do have the top end disassembled. and I ordered a stock chain, I dont have to tools to break/rivet one. :-\
 
The 360 is an "interfering" engine. This means there is no clearance between the pistons and the valves when the valves are open. Normal functioning of the engine aside, if the valves are not open and closed at proper intervals, damage will occur. It may be relatively minor such as bent valves, but can also include damage to the pistons, valve seats, the head, and even the con rods.. Losing a timing chain or timing belt on an interfering engine is one of the more destructive things that can happen. Be prepared to check EVERYTHING.
 
yes I concur that you must now check everything. When you state that the engine was not moving quickly, only at idle, the engine is still rotating close to 1000 rpms...and would likely cause the same damage as if it were rev'd higher.

Bright news! You get to do an engine rebuild and you have the resource of this site to ask q's as you go. Where are you located? Its very possible that a fellow member is close enough to come lend a hand if necessary.
 
You use a grinder to remove heads of pins and a couple of hammers to rivet back together
 
To check the valves the easy way, just use some acetone or gasoline and stand the head on one set of ports with the combustion chamber facing you and fill the top ports with the fluid. IF you see leakage, the valve is not seating.

Flip the head over and do the other side, same deal. Bent valves leak pretty badly, non sealing seats just weep a little.
 
OKay I'll try that leak test in a few hours here...
PJ, I have a guy bringing me a 750 crackcase, so I'm gonna pull that chain and try and work it.
If it all pans out, I'll save the cb360 cam-chain I ordered.

I just found a decent looking cb350 project :)
I promised myself I'll wait till this one 100% before i start the nest :/

Thanks for the help fellas!
 
If it isn't heavy duty parallel side plates, don't bother with 750 chain
 
ahhh man! Always something... :'(
So check these out then, I wouldn;t know if it was heavy duty or not...

Top one are the 750, still on the case, wont bother breaking it if i doesn't work.
haha! nor will i need the case... money loves to spend itself.


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Oh also!
I'm still trying to turn over how i would do this repair, say this was the right chain...
How would i repair it, I get what griding the pin end would do, and getting it out, that all seems simple.
It's putting them back, how could i use ground pins? I need material at the ends to flare em a bit, right?

I'm going to get my friend chain breaker tonight, Ill see if i could just force it through...
Apparently he breaks his 530 chains and rivets em with it, we'll see...
 
the 750 chain is too long, I used a chain from bore-tech for the 350, and a master link, cut 1 link iirc out, and it was correct. Honestly though, every time I did something to upgrade that damned engine, I found the next weak link. the 350 was overbuilt to begin with and is a better platform for making power.
 
Ahhh I see, well could I just take out the amount of link necessary and rivet it shut? better yet! Master link it...
 
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