TOPIC:

Exactly! Thanks for the post.

Excellent post floridamba.
And in stead of using an elctric drill for the Flexi-hone I used a 14,4V battry drill the last two times I deglazed cylinders. It is powerful enough for the job, and it spins slower and are much easier to controle. I also used mineral spirit for cooling the liners, but you can also buy a special honing oil.
And washing the bores with soapy water is still the best cleaning method. Just make sure you oil the bores once the water is dried out. Orelse they will start to rust. And don't forget to measure the bores before, and during the prosess, to be sure you don't remove too much metal.

I have another question about replacing the rings.

As mentioned upthread, a leakdown test showed leakage around my rings that was borderline unacceptable (9%). So while I've got the engine apart, might as well replace the rings.

So, if my cylinders are still round and within spec, do I just replace the rings with standard size rings, or do I need to get slightly oversized rings? Do the oversized rings require a cylinder bore job?

I am trying to see if I can borrow or locate a bore gauge to test the cyls. If they are still within spec, standard rings should be fine, right?

(sorry for such a novice question, this is my first time this far into the engine )

If they are not to far out of round you may be able to hone them and use standard rings. I checked 5 KZ750 four cylinder blocks awhile back, and only one could be honed and still be within the specs.

The only oversize rings I have seen for the KZ required boring and oversize pistons.

If you are within spec for cylinder to piston clearance, and your rings are not worn (determined by measuring the end-gap of the rings, then you may just need to hone the cylinder lightly and the rings will be reseated to the bore.

Sometimes bores get glazed over due to sitting for years and this will help them. You are on the right track.

Rings come in an oversize - I'm not sure with stock Kaw rings but usually they are in .010", .020" over. If your clearances are too large you must rebore the cylinder and replace pistons and rings with the next larger size. It doesn't sound like you will need this though.

My point is that if you would only use oversize rings if you had oversize pistons, and you would need to bore the cylinder (all of them) if you did this.

good luck:P

Thanks. I think I understand now.

I just picked up a set of Tee Bore Gauges at Harbor Freight, so I'll check my cyls for round tonight.

I'll also check all the ring gaps and clearances. That would be great if I can get by without new rings.

One more question. I've read a lot of people talking about getting the rings to "set". Is this something I can see with the head off (the engine's head ), or do I just need to put it all back together and check compression/leakdown again?

Post edited by: Skyman, at: 2006/12/28 18:36

Skyman,

You must be talking about the break-in process where the rings and the cylinder wear in together. This gives the best seal and usually takes a few hundred miles. It is like a new bike breaking-in period.

Okay, my cyls are round, all measurments are between 70.0 and 70.1mm. So far, so good.

But my rings are worn beyond service limits, so new rings and a hone job should do the trick.

Well... not exactly. Your pistons also wear and you may have excessive clearance between the piston skirt and the cylinder wall. Pistons are aluminum alloy and cylinders are steel or iron, so your piston wears as well. This results in piston slap and also prevents the rings from sealing well because the pistons rock back and forth.

From the Kaw manual I have:

Use a cylinder gauge to check the cylinder wall dimensions of each cylinder in the three areas shown (where the rings go, where the piston skirt goes) and take two measurements at 90-degrees from one another, at each location. If anyh of the measurements exceeds the service limits given below, or if there is a difference of more than 0.002 in. (0.05mm) between any two measurements, all the cylinders wil have to be bored and honed. (boring is done after honing to put a final finish on the cylinders)

It sounds like you have done the first step.

Measure the piston diameter at a point about 0.2 in (5mm) up from the bottom of the piston skirt and at right angles from the piston pin holes. Replace the piston if the diameter is under the service limits. For a 1000:
Standard 69.94-69.96mm
Service limits 69.8mm

Replacement pistons are available in .020" and .040" oversizes.

Measuring both and subtracting gives you the clearance between piston and cylinder.

Here are a couple of ideas:

I have an old Kaw manual with single sheets - I can photocopy and fax these pages to you with the measurements if you need them.

I did not see in your post exactly which model this is for - can I assume it is for your 1981 Ebony Kz1000 LTD K1 model?

I have a 1982 KZ1000 LTD myself, and as part of my deal I got a spare motor except for head. It has a block and pistons, and I have been meaning to take the pistons out and measure them in the bore for clearance with the piston skirt. It's one way of doing the measurements with the bore gauges as you are doing.

Do you have any interest in a used block and pistons if they are in good shape? If so I can take the pistons off the rods, and slip them in the cylinders and see what the clearances are. It may be a way to get your bike up and running without spending a lot of money.

I If you are not interested in that route that's ok too, it's sitting in the garage.

floridamba wrote:

From the Kaw manual I have: ... boring is done after honing to put a final finish on the cylinders ....

All excellent info and advice, and just to avoid any possible confusion, the above cite should probably read "honing is done after boring to put a final finish on the cylinders"

Post edited by: Patton, at: 2006/12/29 08:00