Changing my head gasket and have some questions

Hi all,
Recently my xj650j began running bad until running hot and on a hunch I put my hand next to the side of the engine while at a red light, and I could feel some compression blowing out past the gasket. So, I got a top gasket set and I've got it torn apart. I think that I'm going to change the base gasket too. But does anyone have suggestions about what I might use to get the pistons back in? I just got a downloaded copy of the factory service manual for xj650G (is the difference that the G isn't YICS?) and it shows as needed tools: 'Piston Base' and a ring compressor. It looks like the piston base is just a clip to keep the pistons from wobbling around and I can probably make them out of sheet metal. But they show an unusual looking ring compressor. Can I just get two of the regular ring compressors that you use on cars? Or is that type of ring compressor easily available? Do I need two?
One other question: I noticed that the studs for the acorn nuts can be wobbled around. (maybe not all of them - I'm away from the bike now so I'm talking off the top of my head.) But it looks like there was some kind of sleeve that's now deteriorated. Anyone have the downlow on that? Do I have to buy whatever that is? If so, I guess I have to pull the stud out and put it through that sleeve and thread it back in? Right? Are there other intricate little parts that I need to replace?
As usual, thanks so much in advance for all the valuable advice.
Scott Scheffer

 

Install rings on pistons.
Install circlips on the "inside" groove of all four pistons
Generously spread oil on the cylinder walls. Wipe hands dry.
Either using finger pressure (risky) or rent a ring compressor from an auto parts store, and install all four pistons in the cylinder block while it is on your bench. Inner pistons should be just far enough in to cover the rings. Outer pistons should be in further, just so the bottom of the piston skirts are flush with the cylinder skirts.
Install base gasket, locating dowels and any associated o-rings.
Spin crank until two center connecting rods are at their highest point.
Wad some cotton rags into the mount of each crank bore to prevent dropping small things down into the engine.
Get a friend.
Have friend slide the cylinder block over the studs and hold it over the engine while you install the pins and circlips into the inner two pistons.
Spin crank so that the outer two connecting rods rise up to mid stroke. Lower the cylinder block at the same time to prevent pulling the pistons out of their bores. Push the two outer pistons down until you can slide the pins into them through their respective conrods, install circlips.
Remove cotton rags, taking care to catch and remove anything which may have dropped into them.
Lower cylinder block onto engine.

 

The piston base is designed to hold the pistons up and keep them from banging against the crankcase. You can make your own by putting a slot in a stip of plywood. It's essentially a 2 tonged fork (or tuning fork!) with no handle.

An automotive ring compressor will not work. Automotive compressors are designed for you to push the piston through and down into the block. On a motorcycle you are pushing up into the block and that type of compressor ends up trapped around the connecting rod. The strange one in the manual is like salad tongs that open so you can get it out.

I've never done an XJ, but isn't there a chamfer at the bottom of the bore to guide the rings up? If so, you should be able to carefully work them in with your thumbnails.

 

Yep - how I did my 600. My error though was working in poor light (or with deteriorating eyesight) and not spotting the rear chain guide was out of place and preventing the barrels from sliding down - bruised the edge of my hands that night trying to slap it down !

 

how about 4 big screw type hose clamps ?

 

the "sleeves you refer to around the (left side 10 studs only, don't put sleeves on the r/h 2 studs as these are the oilways) , can be replaced using heatshrink tubing , obtainable through most electrical suppliers.

stu

 

Zoinks ! Sleeves - what sleeves ?? Oh well maybe next time..

 

I can't believe the amount of valuable info in all of these threads! Thanks to all. Now I feel like I can do it efficiently, do it right, and be riding my babe again in no time.

 

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Zoinks ! Sleeves - what sleeves ?? Oh well maybe next time..
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the l/h side 10 cylinder head studs have plastic sleeves around them , as they are exposed to the elements where they pass through the cooling fins,
when you pull the barrel off , they usually disintegrate, you can see the old ones here, falling apart


but with some heatshrink tubing "around 15mm dia. should do", no need to remove the studs ,just shrink the tube on with a blowlamp - slowly.
here you go


stu