How to compress rings to install piston into cylinder?

[BigValvedEX]

I am in the process of putting a new piston and rings into my quad and I and am kind of new to the atv motors,...i have alot of experience with rebuilding big blocks and diesel motors but i was wondering what is the easiest way to compress the rings to slide the piston into cylinder. I know on car motors you can put the whole rod and piston together in from the top using a ring compression tool, but on the four wheeler you gotta put the piston in from the bottom and slide the cylinder down, but what do i use to compress it? Do they sell atv motor ring compressors?
also i was wondering what the letters were on a stock 03 400ex piston to see if mine was still stock, just curious, it has "KCY" and "IN" on the piston.

[JOEX]

There is a ring compressor available ot these types of motors, not sure who makes it though. You can just use your fingers, it's a challange but can be done;) I've also used a large hose clamp, not the best tool but it worked.:p

[enduro400rider]

i had to put a piston in my 440 and and i didnt even think of a ring compressor until it was too late, doing it with your fingers is hard as hell, and you will probably slice up your fingers if you try hard enough, i just found an old hose clamp and it worked fine.

[GPracer2500]

I've done it with my fingers and it's kind of a ******. Having a third or fourth hand around helps. Sometimes it can be easier to install the piston in the cylinder on the bench and then connect the piston to the rod. The thing with that method is then you've got one of the wristpin circlips to worry about (don't drop in in the case!).

I always used my hands and kind of twisted the cylinder over them.

[cals400ex]

i use my fingers as well. careful though, i have slit my fingers a couple times on the rings. i do have a ring compressor from craftsman but i find it easier to use my hands. i just think my compressor isn't a very good one though. make sure youdo not bind a ring when trying to put it in the cylinder. i find it easiest to put the piston in the cylinder first and then go put the cylinder/piston on the bike. it does take getting used to. you can only have the piston in the cylinder far enough to cover the rings because you need to be able to slide the wrist pin in and out. so, you may knock the piston out of the cylinder a time or two. then it is pretty tough to align the wrist pin and the rod. you will get it though, just take your time.

[TC426EX]

i wouldnt worry about the problem... just jam the piston and rings in there with a mallet and youll be good to go

[Kaleigh]

if you're gona use your hands get a friend to help you.. it will makes things alot easier..

yea mine were a ***** to get to go in the cylinder i had a friend help me too

and holding the timing chain at the same time :scary:

got it done though :macho

[cals400ex]

Originally posted by Kickstarts_Suck
yea mine were a ***** to get to go in the cylinder i had a friend help me too

and holding the timing chain at the same time :scary:

got it done though :macho


run the timing chain through in advance before you put the piston pin in the piston. then tie it to the frame with a piece of wire or something so you do not have to deal with it

Originally posted by cals400ex
run the timing chain through in advance before you put the piston pin in the piston. then tie it to the frame with a piece of wire or something so you do not have to deal with it

yea i didnt think of that until i was done

[cals400ex]

well, now you know for next time. :)

[Kaleigh]

I did that too.. tie it up.. well I tied it up cause it fell into the case.. dont let it fall into the case.. suck getting it out.. and you dont want it to bind up.. but a wire to the frame helps wonders..

Originally posted by Kaleigh
I did that too.. tie it up.. well I tied it up cause it fell into the case.. dont let it fall into the case.. suck getting it out.. and you dont want it to bind up.. but a wire to the frame helps wonders..


i did that once and i got a wire hanger and bent it so i could pick it up with it

[Kaleigh]

Originally posted by Kickstarts_Suck
i did that once and i got a wire hanger and bent it so i could pick it up with it

we must have followed the same manuel.. lol...:D

[400flava]

there is a tool around that i have used on rebuilding car engines it is kind of liek a big hose clamp but it has a cylinder of sheet metla that it puts tension to so u set up ur rings how they shold be and tighten it the sleve sits on the block and u push the piston down. works amazing for cars should work for this as well i am pretty sure it is a failry cheap tool also

[JOEX]

Originally posted by 400flava
there is a tool around that i have used on rebuilding car engines it is kind of liek a big hose clamp but it has a cylinder of sheet metla that it puts tension to so u set up ur rings how they shold be and tighten it the sleve sits on the block and u push the piston down. works amazing for cars should work for this as well i am pretty sure it is a failry cheap tool also
As far as I know that style of ring compressor will not work on most atv/motorcycle motors. On these types of motors the piston and rod are usually attached to the crank then the cylinder is lowered into place over the piston.

It may be helpful using the method GPracer stated though...

[bwamos]

Aye, not enough room for that big beast.

I just installed it with my hands. But, I imagine a large pipe clamp would work awsome.

Originally posted by JOEX
As far as I know that style of ring compressor will not work on most atv/motorcycle motors. On these types of motors the piston and rod are usually attached to the crank then the cylinder is lowered into place over the piston.

It may be helpful using the method GPracer stated though...

yea thats what i though