‘76 KZ900 LTD. Need some advice.

Yeah, and I have to admit, I’m probably at fault for not doing the tensioner maintenance often enough.

I had exactly the same thing happen, and when I tore it down I found that the cam chain roller and idler sprockets were worn down badly and the cam chain was stretched out. I ended up replacing the whole kit and caboodle; Liska racing makes stuff that seems far more robust than OEM.

Today I measured the bore of the liners. 70mm. Isn’t 66 the stock bore? I’m the second owner so may the guy before me put in a piston and liner kit? It would make sense I suppose because of what I mentioned earlier about the liners just sliding up out of the cylinder when I set it down on a flat surface.

Second, to measure lift on the cams, wouldn’t a guy just measure the diameter of the cam then measure the total diameter to top of lobe and just do the math? I’m getting right at .276 but that sounds low to me. 

Those loose liners are a concern.  They should be a press fit into the cylinder.  I'm not sure what the remediation steps would be, other than maybe getting a new block.

What does it say on the block 903 or 1015cc? 
Steve

Your bike was stock 66mm bore. If it’s 70mm, then either the block has been swapped out for a 1000 (1015), or the 900 block was bored and the 1000 sleeves installed. That might explain why they don’t fit. This is assuming the the 1000 sleeves vs the 900 are a larger OD. I have never thought to check. 

I don't think the 1015 sleeves will fit in the 903 block. I'll Check tonight. 
Steve 

SWest wrote:

What does it say on the block 903 or 1015cc? 
Steve

903
 

The pistons themselves measure under 70mm and the cylinder is for sure stamped 903. I’m not so much concerned with the sleeves not being tight in there as I am needing to know what new rings I should order. Would be stupid imo to put this thing back together without at least new rings.
 

The 1015 sleeves will not fit into the 903 block unless it's been bored to accept the larger sleeves. They may have spun while boring.
Steve
. 

Mikaw wrote:

Your bike was stock 66mm bore. If it’s 70mm, then either the block has been swapped out for a 1000 (1015), or the 900 block was bored and the 1000 sleeves installed. That might explain why they don’t fit. This is assuming the the 1000 sleeves vs the 900 are a larger OD. I have never thought to check. 

This is slightly incorrect.
The stock 900 liners can be bored to 71mm ( 1045cc) so it's likely they are on the stock max 70mm oversize on stock liners.
1000 liners are a larger OD so a 900 block needs boring for them to fit.
Loose sleeves are not uncommon either because of factory tolerances or they've been cold pressed out and back in which drags material from the alloy block and lessens the fit..
 

zed1015 wrote:

Mikaw wrote:

Your bike was stock 66mm bore. If it’s 70mm, then either the block has been swapped out for a 1000 (1015), or the 900 block was bored and the 1000 sleeves installed. That might explain why they don’t fit. This is assuming the the 1000 sleeves vs the 900 are a larger OD. I have never thought to check. 

This is slightly incorrect.
The stock 900 liners can be bored to 71mm ( 1045cc) so it's likely they are on the stock max 70mm oversize on stock liners.
1000 liners are a larger OD so a 900 block needs boring for them to fit.
Loose sleeves are not uncommon either because of factory tolerances or they've been cold pressed out and back in which drags material from the alloy block and lessens the fit..

 

If the liners are as loose as they appear to be, will they not "rock" forwards and backwards during normal running causing the block to oval and the liners to chew the head gasket ?