Timing chain chaos-- replacement options?

KZ Riders,
I've got a situation. Thought I'd see what you all think.

About a year ago, my timing chain jumped the tensioner. It chewed into part of the steel arm that holds that stupid rubber wheel on the tensioner. Also wore away some of the aluminum in the cylinder block chain passage. Plenty of little metal particles.

So I am replacing all the tensioner components. Might change the head, since some metal particles wound up in there. Probably changing the oil pump too, just to be safe.

Basically, rebuilding the top end, cleaning the engine out as best as I can-- and then flushing the engine to get any residual fine particles out of there.

Bottom end seems fine.

The cam chain shows surprisingly little sign of wear, given that it came into contact with the tensioner and the cylinder block.

Please correct me if I'm wrong, but the cam chain seems to measure well within in spec-- 20 pins per 15 cm. There is a little side-to-side play between the links-- don't know if that is normal.

So, what do you all think? In your experience could this chain still be good, or does it have to be replaced? If it needs to be replaced, is there a good option for replacing this without splitting the cases (i.e. a good master link replacement, or any other option)?

All thoughts appreciated. Thanks very much.

KZ200? KZ1300? Ed

Sorry-- 1978 KZ1000B2 (ltd).

I actually just measured the cam chain in question against a known good chain, and they have the same exact measurements-- both in terms of stretch (20 pins per 15 cm) and side-to-side play/link width.

What you all think?

There is a spec in the KZ1000 manual for how to measure cam chain stretch. I've forgotten the details and don't have my book in front of me, but here is a tale of woe that might help your thinking.

I recently restored a Z1B 900, having torn the engine down to the crankshaft. The speedo said 45,000 miles, so I thought time for a new cam chain. I knew I had a new one, but couldn't find it, so I checked the old one and it was within the stretch spec so I reused it. The chain was loose at the top sprocket idler but I figured it would be fine so I finished the rebuild and fired up the engine. Somehow it jumped the sprocket. In the process three valves were bent, but luckily no further damage. I ordered a new endless loop chain (and valves) and pulled the engine all the way apart to put in the new one when it arrived. Lots of work for nothing.

If you're really strapped for $$ and assuming the chain measures within spec I would try it and check the slack at the top sprocket idler. If the idler doesn't tension up on the chain I would replace it.

Here is a photo of the finished product.

I would replace the chain with a new endless one .
Cheap insurance after all the work and other cam chain drive parts you are replacing
Dave

Just get a new chain and since that engine uses the same oil for tranny and engine I would also split the case and clean out any metal shavings in the lower end also.

The crank main bearings have what could be called jets or reducers in them. One particle can clog one starving it for oil. I'd tear it down and do it right.
Steve

Alright. Thanks for all those responses. Seems the smart and responsible thing to do is split the cases, pull the crank and swap out the chains.

I just consulted my Clymer manual and was pleasantly surprised to see that I can do this without having to disassemble the transmission. Looks like I've got to pull the clutch, the stator and the shift linkage, then pull the cases apart. Then pull the crank and replace the chain.

That right?

Since I already have the top end off the engine, this doesn't seem too painful. Anyone out there advise me of any hidden landmines I'm about to step on with this optimistic outlook?

All thoughts/information appreciated. Never done this before.

Be sure to get all the small bolts top and bottom. Split the cases upside down sitting on the cylinder studs.
Steve

Clean all parts including ALL oil passages with solvent , Air and oil to flush out any metal shavings.
Impossible to do to good a job of cleaning
And throw away the Clymer manual and get a Kawasaki factory manual.
Please feel free to ask for more step by step advise
Dave

Thank you all for the great thoughts and advice. I'm going to tear into this and get the job done right. Three questions:

1.) does anyone have a Kawasaki factory manual for a 1978 KZ1000B2 (ltd) they want to sell or donate? If so, please send me a message.

2.) on the cleaning: what solvents and oils should I use? Dave, did you mean a spray down with something like carb cleaner and then compressed air to blow something like MMO through the oil passages? Also, what do you all recommend be used on things like the crank bearings?

3.) what kind of sealant should be used on the mating surfaces of the cases when the two halves are bolted back together again?

Again-- thank you all for the help and information.

I use diesel for cleaning and flushing. Compressed air for blowing out the orifices and Yamabond to seal the crankcase.
Steve