GPz750 cylinder install

So assuming one doesn't own the special Kawasaki tool that holds the pistons in place, centered and upright, when installing the cylinder barrel, what's conventional wisdom on best approach? Middle cylinders up and locked, slide the barrel down, rotate crank and position outer cylinders and repeat? Outer first and then inner? Or all at same position? Any tips on locking the crank in place and positioning for an easy assembly greatly appreciated!! I've never done one of these, the last engine was a Laverda triple with a 120 crank. It was kind of interesting but the assembly went pretty well. Better yet it still runs!

Thanks, Richard

I made some piston holders from some thin paint stir sticks I got from Home depot. I cut them into shorter lengths and duct taped them together until it was as tall as I needed. The point is to rotate the crank until the pistons are firmly setting on the holders and can't rock while you isntall them.

I haven't done a four, but the approach I would us is do the middle pots first with them up a little higher than the outers. Put the piston supports under middle ones and clamp the rings. Lower the cylinder slowly and get it just started over the first ring. Tap down slowly adjusting the clamp pressure as needed. Remove the clamps and piston holders. Rotate the crank raising the pots already in and the cylinder will raise with them. Get the outers high enough to get the supports under them and apply the clamps. Tap the cylinder down onto them and then remove the clamps and supports.

Some things I learned:

1) Use fine sandpaper and polish the inside of the clamp bands to maki the things slide easier.

2) Use plenty of oil on them.

3) Oil rings break REALLY EASILY....

4) Draft an assistant to help because you are trying to support and guide the cylinder down, wrangle the pistons and clamps and also adjust the clamp pressure just right.

5) if the clamps are too tight, they will not let the cylinder down. Too loose,a dnthe cylinder will hang on the edge of the ring.

6) tap lightly, go slowly, and keep checking to make sure a ring has not popped out of the clamp and is blocking the cylinder.

Like 'bountyhunter' said, do the middle pots first...but I am assuming you don't have any of the special tools that hold the pistons AND rings clamped?!?! If not, then it becomes a bit trickier...some folks have said they can do a four banger by themselves w/out the special piston tool. I am not so talented but I am blessed with an exceptional wife who's not afraid to dive into a bike's innards. I have found that it takes two hands per piston to compress the piston rings sufficiently to slide into the jugs...she on one side of the bike, me on the other...center pots first, then the crank is slowly rotated and the jugs lowered onto the outer pistons and repeated until all pistons are in the jugs.

It occurred to me later that, assuming you have four clamps, it could be possible to do all four at once. You would have to position all four pots level across the top and then come up with a wooden block or support that would just slide under the pistons to support them.

I am not sure this would be easier, I think fighting two at a time is hard enough.....

Somebody has suggested using large hose clamps are ring compressors. I have not tried it, but they are cheap enough you could buy four if you wanted to.

In the past I've used ring compressor and cut the band to the needed width, getting at least two from one. Then I wrap the compressor band around the piston, then a clamp around the band, tighten, and go from there. This one's just different for me as it's my first four. The suggestions above make sense to me.

Richard

bountyhunter wrote:

Somebody has suggested using large hose clamps are ring compressors. I have not tried it, but they are cheap enough you could buy four if you wanted to.

They are, in fact, exceptionally cheap, and I have tried this technique...it sounded incredibly simple when suggested to me..I went back to my two-fisted approach as the design of the hose clamps doesn't permit the leading edge of the sleeve to cover the compressed rings without bumping into the hose clamp...the Kawasaki ring compressors have the clamp offset to allow the sleeve to slide over the rings:)

When I was putting together my buddy's Spectre, I removed the pistons from the rods, used one ring compressor tool to slip the pistons into the sleeves, rotated the crank until 2 & 3 were up, installed the wrist pin & retainers, then rotated the block until I could so the same 1 & 4. Yes, it's tricky and I took me two tries to get it, but it worked. It helps to have some short pieces of 2x4 to use as props to hold the block at the right height.

Mcdroid wrote:

bountyhunter wrote:

...the Kawasaki ring compressors have the clamp offset to allow the sleeve to slide over the rings:)

That's the best design. I ended up with the standard kind with a straight band. Harder to use, you have to get the tension just right to hold the ring enough to let the cylinder slip down and not clamp too tight. I popped a ring on the second rebuild, not sure how.

BTW: you may want to file a little bit on the "bevel" at the base of the cylinder to help it get over the edge of the ring.

guitargeek wrote:

When I was putting together my buddy's Spectre, I removed the pistons from the rods, used one ring compressor tool to slip the pistons into the sleeves, rotated the crank until 2 & 3 were up, installed the wrist pin & retainers, then rotated the block until I could so the same 1 & 4. Yes, it's tricky and I took me two tries to get it, but it worked. It helps to have some short pieces of 2x4 to use as props to hold the block at the right height.

Good one. I thought of that and couldn't do it. The tolerance fit of the wrist pins to the rods and pistons on mine is so tight I couldn't get them to line up that way.... in fact, it was hard to get the pins through without the cylinder! The pins were a press fit, zero tolerance at all.

Couldnt you use cut aluminum from pop cans to fashion a sleeve out of that would be thin enough to go into the jug with the piston? Then be removed once the rings clear the edge? maybe with the help of a hose clamp?

Qdude wrote:

Couldnt you use cut aluminum from pop cans to fashion a sleeve out of that would be thin enough to go into the jug with the piston? Then be removed once the rings clear the edge? maybe with the help of a hose clamp?

I don't think so. The piston to cylinder clearance is only a couple of thousandths.