TOPIC:

Trying to put my '81 KZ 550 A2 back together...specifically the top end. Saw a ridiculously simple video on U tube of how to get the pistons back in the cylinder without a ring compressor. That didn't work and nothing I could find in the way of a tool worked when they are still on the connecting rod and in the bike. So, has anyone got a trick they care to share? I don't see any earthly way to get the rings or any compressors past the bevel of the cylinder wall. A friedn told me that should help compress the rings. But on close inspection of the bevel, I found ridges that are grabbing the rings and preventing any movement. I have ordered another set of rings only because past attempts has me worried that the leading edge of the top rings have been damaged from the many attempts

Hi Gman - I feel your pain; I've run into this problem before, and it can be a royal PITA. Have you tried using worm gear clamps (aka radiator hose clamps) as ring compressors? I've had good luck with that. You can also cut 3/4" strips of soda can to wrap around the rings before you use the clamps; this is especially helpful if the ring grooves are wider set than the width of the clamp. Be careful and don't cut yourself - on either strips of soda cans, or the rings themselves.

Also, try cutting a piece of plywood that fits between the bottom of the cylinder block and the top of the top crankcase. It will need to have four U shaped cutouts in it that will allow it to slide around the connecting rods. It sits there temporarily and holds the pistons level and in place so that you can get the cylinder block over all the ringed pistons. As you've surely noticed, it's hard to handle all four rods/pistons at once, especially with everything covered in a nice slick of oil. Once you have the pistons inserted, you withdraw the piece of wood. The exact dimensions of this wood block will vary depending on your engine, but should be described in your repair manual.

I hope this helps - good luck.

I have a set of ring compressors you may borrow if you would like. There are 2 sets of them I bought from PIT POSSE for doing my KZ. I will ship them to you for whatever it costs me from 28468 zip. They work great. PM me if you want them. jon

I should have taken a clip of my putting mine in. I do 2/3 first then 1/4. I use short pieces of 1X4 to hold up the pistons. Hose clamps the right size will compress the rings. Once you're set up on the first ones, you loosen the clamps just enough for them to slide into the cylinders. A light coat of oil helps. If they won't go in, don't force them. Start over until you get the feel on things. When you get the first set in, the second will be easier.
Steve

If you decide to use the hose clamp method ..... Make a few (maybe 4 or 5) outside dents (larger than the cylinder base) in the top edge of the hose clamp (where it meets the bottom of the cylinder) so that the hose clamp does not want to slide into the cylinder. That's how a piston ring compressor actually functions. I would recommend, that when you tighten the hose clamps on the rings, MAKE SURE THE RING END GAPS ARE IN THE CORRECT POSITION PER THE FSM and as you tighten the hose clamps ..... tap the clamps VERY GENTLY and keep tightening until you're sure they rings are fully compressed. I personally would oil the rings before doing this and make darn sure there rings grooves are smooth, clean and your ring clearance AND end gap are correct. Please elt us know how you make out. Be well, jon

Can you carefully take a file to the ridges on the bevel.... Jay from APE told me to just use wood sticks and my fingers to compress the rings (like stated make sure they are gaped, oiled and positioned right first) and they slipped right in doing 2/3 first. I'd oil the cyl and piston skirts well too a few on here do em dry and I shutter every time I read that. The pop can and clamp trick sound good too but was pretty easy Jay's way..... aquaholic's offer is nice of him too... what ever way you feel the most comfortable with.

On the 550 and 1000, I never had any issue using fingers, assembly lube and patience. Put a safe prop under the head so you can work withot the head weight bearing down to smash you fingers. YMMV. R

rrsmsw9999 wrote: On the 550 and 1000, I never had any issue using fingers, assembly lube and patience. Put a safe prop under the head so you can work withot the head weight bearing down to smash you fingers. YMMV. R

Head? Smashing fingers? What are you referring to?

I never need or use a ring compressor tool for piston installation.
I compress the piston rings with my bare fingers into the sleeves first with a lot of lubricate.
Put all 4 pistons half way into the cylinder block first with the inner circlip installed.
Push piston #1 and #4 deeper into the sleeve to get full access to #2 and #3.
Then push piston pin into #2 and #3 and install outer circlip and turn the crank 90 degrees ( #2 and #3 piston goes deeper into the sleeve).
Then position cylinder block to push piston pin into #1 and #4 and install outer circlip.
Quick and Easy and never get headaches with this method.
Don´t forget to covering the crank case with paper towels if you want to loose some circlip into the deep of the crank case.

Michael

I did a similar method to Scirocco, but installed the pistons through the top of the sleeves with a tapered compressor.

With 2/3 up lowered the block and slipped in the pins and caps (no snap rings on MTC). Then rotate and repeat on 1/4. Works best with a buddy positioning the block while you install the pins.

I use a small wood block for a spacer because once the last set of rings is inserted in the sleeve, the head will drop down. Watch your fingers. R

A few nights ago while laying in bed I was thinking the same thing...why not install pistons in the barrels 1st then connect the rods and wrist pins... thank you for reinforcing my thoughts... thank you Scirocco