O-ring help

[Antonn3]

Hello,does anyone know the size of the large o-ring that is around each cylinder  "liner", .....visible when you take the jug off.
Part number 93210-77363-00. I threw original ones out during the rebuild
I purchased a gasket kit a while back but the ones that came in the kit are too thick at around 2.4mm and wont fit in the groove. I dont recall the sellers name. Im thinking 1.5mmx80mm ID would be correct?
what purpose do they serve? if you look closely... they dont line up with the mating surface on the lower case.
.......thanks in advance

[FJ111200]

2mm x 81mm, if my digital gauges are to be believed. 
I measured the outside diameter of the 1100 liner and a new ring thickness, which is definately bigger than 1.5mm.

[racerrad8]

They were supposed to prevent oil from seeping up between the cylinder wall & aluminum jug. They swell up & deteriorate in short order.

You do not need them, I have never install a set in the 143 motors I have built.

Randy - RPM

[Antonn3]

Thanks for the much needed help.....ok and heres the big question ..how  do you install the jug back over the pistons? I have done a search but no definitive answer. I have tried installing the pistons in the bore first, then onto the rod, no luck.. I tried compressing the rings using clamps and my fingers, no luck ....can't use a conventional ring compressor as your not able to take it off afterwards....ideally you want the kind of split ring compressor that you spread to place over  the rings.. ideas?
Thank you

[Seanextra]

Quite easy ! Well its not real easy you must take time and make sure you have rings positioned as per the manual lower the cylinder block over the pistons and the work your way one ring at a time into the taper gentle pressure on the cylinder till you get them all the way into the bores . Take care not to break rings as they are brittle , take care not too let the oil scraper rings ride out of their grooves, Its not that hard but take your time and you will get it ive spilt some blood in the past but not any more. I have tried many different ways like using large Zip Ties and PVC pipe slit down the sides using a small diameter pipe but in the end its just easier to do it by hand there is Very little room for compressors on most inline 4 bikes as you have noted. 

Best of luck!

[andyb]

A ring compressor with handles can do it.

With some care, popsicle sticks can do it.

You can install the pistons in the block before you start, and then put the rods to them, which is a little fiddly if you're using circlips.  I've got buttons, and this is the easiest that I found.

You can use hoseclamps (with something between them and the rings so they don't scratch) and take them off when you get where you want to be.

[ninjamuder]

big fat zip ties work good, also, they arent prone to scratching.......done em this way for a few years, and it works really good, the trick is DONT snug the zip tie down too much, or it will hang on the edges of the rings, and basically lock in place.....a little engine oil to slick things up helps too............along with a willing, and patient extra pair of hands to hold the block..........