how to change piston rings

MySpree · Post by **MySpree** » Sun Mar 12, 2006 7:39 pm

you Will need a new head gasket to change your piston rings, available at your local Honda dealer.

The first thing that you need to start changing your piston rings is a 10mm ratchet, this is to take off the cylinder bolts.

once you have the head off

you can see the piston and a mark on the top of the piston reading EX that stands for exhaust, this marking has to be facing you exhaust flange. there will be carbon build up on the piston so the marking may not be readable until you clean the piston, i recommend carb cleaner then washing it off with water.now you are ready to re move the cylinder, just pull on it until it comes off, your base gasket may make this hard to do because of your base gasket sticking to the cylinder.

once removed you will see the piston connected to the crankshaft, stick a clean rag into the crankcase to make sure no foreign debre falls into the crank case.

next you will have to remove one of the clips holding the piston rod in.

once removed get a flat head screwdriver and push the rod out of the opposite end of were you remove the clip.

once out you will be able to remove the piston.

there will be a little Bering inside of the loop were the rod went, you will be able to see once the piston is out, just slide it out and check if its all there, then slide it back in.

the piston ring should be seated in the groves in the cylinder, if you inspect is closely you will be able to see a rise in the piston rings grove, this should line up with there the piston rings are slotted.

then you will be able to slide off the top and the bottom piston ring, you slide it off up so it you don't score the sides of the piston. there is a difference between both ringe so know which on is top and which on is bottom, the top is more silvery that the bottom in new rings.

then you will be able to slide the new rings right on. they will flex a little before settling in there rightful groove, remember to put the bottom ring on first.

you will need to oil your rings before you slide on the cylinder, making sure that the piston ring slots are at the piston grooves, hold the piston rings tightly to the piston while sliding on the cylinder, for a good seal without getting a new base gasket use gasket sealer to make the seal perfect, make sure not to get any into the crankcase. one your cylinder is on it is as simple as bolting the new head gasket in in place of the old gasket and you are good to ride!

darat · Post by **darat** » Sun Mar 12, 2006 8:17 pm

dude that is cool how u did that

jbarb · Post by **jbarb** » Sun Mar 12, 2006 8:47 pm

Very nice. I was just out pulling my head off and I think I found my problem. Both clips are missing. Im pretty sure I need a new piston. The cylinder is slightly scored but Im hoping its useable. The piston has some pretty good scoring though.

Im hoping those clips got shot safely out the exhaust. Nice tutorial.

MySpree · Post by **MySpree** » Sun Mar 12, 2006 9:45 pm

noiseguy i spent major time on this so could you maby put it in the tec docs??? i think it owould help ppl...

jbarb · Post by **jbarb** » Mon Mar 13, 2006 12:31 am

So is there supposed to be a clip or something where the ends of the ring come together? I was thinking there was something missing where my ring ends come together.

Should I just take my head down to the Honda dealer and have it bored and get an oversized piston and rings?

I could probably get a used motor for the same price.

85stroka · Post by **85stroka** » Mon Mar 13, 2006 2:09 am

jbarb wrote:So is there supposed to be a clip or something where the ends of the ring come together? I was thinking there was something missing where my ring ends come together.

Should I just take my head down to the Honda dealer and have it bored and get an oversized piston and rings?

I could probably get a used motor for the same price.

there's no clip where the rings meet the ring locator pin
there's only piston pin clips x2
You dont need to take the piston off if your only changing rings
You cant bore a head? you can bore a cylinder,if your boring a cylinder you need to have a oversize piston fitted .25,50,etc in thousandths.
If you have a machine shop in mind that do the work -why not go there?

jbarb · Post by **jbarb** » Mon Mar 13, 2006 2:41 am

Ok, upon further inspection, there is a peice of my piston missing. The peice broke off and scored the * out of my piston. The cylinder looks a little scratched from where the rings meet.

Post by **noiseguy** » Mon Mar 13, 2006 1:02 pm

Nice work Myspree. You should be able to copy/paste it yourself now.

That piston is toast. I'd figure out how much you need to overbore at the shop and buy a piston to match. BTW, if you can get a 2mm overbore (which is more than a "clean up" bore,) Maddog can get JCC pistons to fit. They're 43mm rather than the stock 41mm. Includes pistons, rings, circlips, and pin.

MySpree · Post by **MySpree** » Mon Mar 13, 2006 3:03 pm

o im good... dont worry i know thats a bad piston...

Post by **noiseguy** » Mon Mar 13, 2006 11:40 pm

Jbarb's is toast. And yes, the piston from the teardown is too.

myhonda · Post by **myhonda** » Tue Mar 14, 2006 12:09 am

your not alone jbarb my piston looks exactly the same right now.

jbarb · Post by **jbarb** » Tue Mar 14, 2006 3:12 am

What are your plans on fixing it? The dude at the machine shop said I could probably get away with a 42mm bore if I can find the piston for it. Either that or go with the 43mm. Of course if I just bored it slightly over this time, I can possibly get one more bore out of this cylinder before I have to scrap it and find another one.

If I go straight to a 43mm, I think I'll be screwed if anything happens.

MySpree · Post by **MySpree** » Tue Mar 14, 2006 7:54 am

yea... man i jsut sold my las piston and cylinder last week...

darat · Post by **darat** » Tue Mar 14, 2006 8:40 am

so would a 2mm make a difference??

Post by **noiseguy** » Tue Mar 14, 2006 10:00 am

The 2mm overbore should give you a litte more pop, esp. if you combine it with a light porting on the exhaust side. One of the shop I've talked with (SNS in Wayne) mentioned that they'd played with reporting a Spree jug. The only thing they did that worked was raising the exhaust port .5mm, which means they would also have to have removed the top ridge of material.

If the machinist is telling you you need to go 1mm over to get the scratches out, the jug is already ruined for small Honda-parts overbores, which only go up to .5mm over. If that cleans it up, you can use Honda parts.

Contact Maddog on those OS pistons (and I believe he can get stock sizes too.) It's actually a much less expensive route than stock parts, even with shipping from HI.