Broken Exhaust Cam Chain

[will e.]

Me and my baby have been through a lot together. Recently finished an engine rebuild where I replaced a piston and did a lot of work on the valves. But now after the first thousand miles my exhaust cam chain broke. Not feeling very eager to disassemble the top end again if I don't have to. Trying to think through if it's possible to pull the pistons out the bottom end rather than pull the jugs off the pistons to get the new exhaust cam chain back around the crankshaft. Has anybody ever tried this?

If I can pull pistons out of cylinders without damaging anything.
Re-hone and replace piston rings without damaging camblock, valves.
And reinsert pistons into cylinders with 1 & 4 at TDC.

Any advice in this regards other than buy a new bike? If I was going to do that I would have left her in nowhere Pennsylvania that time she broke down and I got stranded there for a couple days.

[TOOLS1]

Sorry no way to remove pistons out the bottom. Have you tried fishing a piece of mechanics wire down, and around the crank? I have done this before, and pulled the chain around that way.
TOOLS

[will e.]

Hey Tools,
I've read/watched videos about that before but was always a little skeptical about the longevity of it. Taking a dremel to the ends of one of the connecting rods to break the cam chain. Feed it under the crankshaft with wire and then re-welding the end of the connecting rod. Given the extreme speed at which that chain runs through the engine I would think that to be a temporary fix, but seeing as how you've actually done it maybe you've had better experiences?

Would love to not have to break this engine open again for at least another 20,000.

[TOOLS1]

I have heard of people spot welding the cam chain master link plate on instead of using a rivet tool, but it is something I would never feel comfortable doing. I use clip type master links for them. They are available on ebay. The older Honda's like the Dream models used them. However I have heard about master links with a pressed on plate that does not require any special tool to install it, but I have not used one yet.
TOOLS

[will e.]

I'm guessing you ride an SOHC Tools. My baby is DOHC. I kind of vaguely knew that the cam chains were different but decided to do a little research. If anybody ever cares to be dorky enough This is everything you've never needed to know about chains. The DOHC uses an inverted tooth chain, which is known for being quieter but to my knowledge they are solely solid link chains. Which means there is no way that I could snake one around the crankshaft without disassembling both the top and bottom ends of the engine. Anything but the exhaust cam chain.

Considering looking for a new engine but they're rarer in the NY area. Just heard a story from a coworker about a guy who broke down in nowhere Montana on his KZ and just happened to find a motorcycle graveyard nearby with a suitable replacement engine. Lucky bastard.

Thanks for the advice Tools. Engine is out of frame, brought her back home to Brooklyn, will probably begin disassembly tomorrow. If nothing else I do love taking apart engines. Just wish I had something to ride in the mean time.

[TOOLS1]

"I'm guessing you ride an SOHC Tools. My baby is DOHC. I kind of vaguely knew that the cam chains were different but decided to do a little research. If anybody ever cares to be dorky enough This http://chain-guide.com/applications/1-6-3-inverted-tooth-chain.html is everything you've never needed to know about chains. The DOHC uses an inverted tooth chain, which is known for being quieter but to my knowledge they are solely solid link chains. Which means there is no way that I could snake one around the crankshaft without disassembling both the top and bottom ends of the engine. Anything but the exhaust cam chain.

Considering looking for a new engine but they're rarer in the NY area. Just heard a story from a coworker about a guy who broke down in nowhere Montana on his KZ and just happened to find a motorcycle graveyard nearby with a suitable replacement engine. Lucky bastard.

Thanks for the advice Tools. Engine is out of frame, brought her back home to Brooklyn, will probably begin disassembly tomorrow. If nothing else I do love taking apart engines. Just wish I had something to ride in the mean time. "

That's the primary drive chain in that link, not the cam chain!
TOOLS

[will e.]

In my engine, a 81, all chains are endless and are the inverted tooth kind. My manual refers to the chain that broke as the "exhaust cam drive chain." Transfers power from the crankshaft to the exhaust cam. I think were just calling it by different names Tools? Here's some more good info on chains. This guy says that whenever he's in there he almost always replaces these chains. Not bad advice considering the situation that I find myself in. But I do love getting my hands dirty.

[will e.]

So I learned a hell of a lot more about chains, pardon my earlier ignorance Tools, and discovered that there are several ways to reattach inverted tooth or silent chains. To my knowledge I have yet to find a rivet tool specifically designed to hold and break inverted tooth chains (there are also several varieties, as well as manufacturers that use different link pins). After having read and researched the hell out of all of these things I sat down and did some thinking about how I was going to go about cutting and then reattaching a new chain when I realized that if the chain had snapped there almost inevitably would be valve damage involved and damage to the cam chain guide.

There was.

So here ladies and gentlemen is some engine porn for you.


Cleaning the mating surfaces with brake cleaner and a lot of patience.

Primary Shaft.

Running rich on the surface of the moon.

Naked.

I might have saved myself from cracking the crankcase if I had still cut and reattached the drive chain, all of the damage was from the cam block up, but if I'm taking off the cams I mine as well dig in and go all the way.

[hellsford]

For future reference guys, if you're having problems finding an engine for one of these old CB's (or just about any other part for that matter) you might give this hidden gem I found a call. It's called Ron's Cycle Land in Tulsa, OK. They've got an indoor salvage yard of old bikes, majority of which are old honda's. I just about lost it when I saw how much they had there. Prices are also very low compared to most online sources.