Piston Kits

[Lexxuk]

Bonjour! I decided that I'm going to get off my rather pert, and sexy, and down right irresistable arse, and fix my motorbike, myself, cause I'm a genius (that and it gives me a chance to use that torque wrench that cost a small fortune, not that a piston needs it, but still, I can use it as a hammer :D). Anyhow, my bike is a Kawasaki KMX125, and, the piston went bang, or pop, or, well, whatever a piston goes like to loose compression.

Now, looking around on the net, i came across a..

PK186 Kawasaki Piston Kit STD KMX125
PK187 Kawasaki Piston Kit KMX125 + 0.50 (Resleeved)
PK188 Kawasaki Piston Kit KMX125 + 1.00 (Resleeved)

Which means bugger all to me to be honest, it says "Piston Kits come with Rings, Gudgeon Pin, and Circlips", now, the rings, are, the round things yes? The Gudgeon Pin, umm, its related to a pidgeon? And the circlips are what you use to fasten your trousers when your riding a cycle so you dont get stuck in the chain? Yes? No?

Anyhow, any engineer type people know roughly what I need to redo my piston (bearing in mind that the KMX125 cant be re-bored).

[virgil caine]

You first need to pull it apart and see what kind of shape its in. If not seized and in decent condition. Take cylinder to a machine shope and ask them to "hone" the bore. then just use the std kit.
And use the best oil you can find from now on.
You might also just look it over and decide that you need a set of rings as the old piston does not necessarily need to be replaced. Just change the rings, may not need anything else.

[cRazy2003]

the resleeved is the size of the piston sleeve around the cylinder which you can replace, so you'll need to know the size of it, the piston kit should come with everything, if not your best bet is a professional opinion because we cant see exactly what make your engine is, it may be a kmx125 engine but it can vairy, hence why theres different piston kits.

[slaughteruall]

PK186 Kawasaki Piston Kit STD KMX125
Ok basically this is just the standard piston that is not oversized at all.


PK187 Kawasaki Piston Kit KMX125 + 0.50 (Resleeved) Oversized by .50 what ever form of mesurment the site you are looking at uses.


PK188 Kawasaki Piston Kit KMX125 + 1.00 (Resleeved)Oversized by 1.00 what ever form of mesurment the site you are looking at uses.

Once you take your motor apart and look at your bores (where the pistons are) if there are groves and what not you should get it bored and honed. Which is why you can by oversized pistons.



Which means bugger all to me to be honest, it says "Piston Kits come with Rings, Gudgeon Pin, and Circlips", now, the rings, are, the round things yes? The Gudgeon Pin, umm, its related to a pidgeon? And the circlips are what you use to fasten your trousers when your riding a cycle so you dont get stuck in the chain? Yes? No?

Yes the rings are almost a complete circle and go aroung the top of the piston is some groves.
The gudgeon pin is not related to a pidgeon. Good guess tho. The pin goes in at the bottom of the piston. It usually gets pressed on.

That circlips i'm not really sure. It might be that your gudgeons are not press in's. It might have to go on one end to hold it into place. I'm not sure on this one thou.

Slaughter

[Lexxuk]

Once you take your motor apart and look at your bores (where the pistons are) if there are groves and what not you should get it bored and honed. Which is why you can by oversized pistons.

Because of something which I cant remember (cant find manual) the KMX125 I got cannot be re-bored, not sure about honing, cause no idea what that is :D


it may be a kmx125 engine but it can vairy, hence why theres different piston kits.

Its err, a KMX engine, from an F reg KMX :angel:


You might also just look it over and decide that you need a set of rings as the old piston does not necessarily need to be replaced. Just change the rings, may not need anything else.

I' guessing that would be no visible scoring on the piston/barrel/thingymabob?

[Gotterdammerung]

circlips are circular clips with a gap on them and 2 small holes. The circlips hold the gudgeon pin in place (the gudgeon pin is really a smooth & hollow cylinder thats about the size of your forefinger, it's what holds the piston to the connecting rod).

Chances are the block is aluminum and you have stainless cylinder sleeves so if it's scored or gouged it's easier to just purchase a new one instead of taking it to be bored.

But lemme explain something, theres the right way to do it and the cheap way which will most likely cause you more headaches in the future. You don't just remove your pistons, replace the rings & stick them back in. You should have the cylnders lightly honed or polished, you shold have the piston crowns cleaned & polished. Naturally if you are removing the pistons you'll be disconnecting them at the lower end from the crankshaft, you'll need to replace the rod bearings as well and you'll also need a specialized ring compression tool to enable you to fit the pistons back into the cylinders. It's really not a job to take lightly no matter how smart you think you are. Being that a few of the parts mentioned you aren't familiar with would lead me to suggest that you pay a few extra bucks and have a pro do it.

(p.s. I also neglected to mention the cost for all the gaskets you'll need to replace)

[Original monk]

i dont understand what you guys are talking about, its something moto yeah :P

but its intresting :)

[Lexxuk]

i dont understand what you guys are talking about, its something moto yeah :P

but its intresting :)

Ditto, so I guess I'll stick with Gotter's idea, and get someone else to play with my bike. Though when my NSR's piston blew, cost me £300 to get it all fixed up again, so *cries*

[rogo]

Id also highly suggest you DO NOT GO TO A DEALER.

Ask some friends if they know any mechanics.

Whenever I ever have a problem with my bike, I give my buddy at work's brother a call.

Hes a helluva lot more honest than any dealer. Not to mention he will sit down and explain the problem with me and show me first hand...so I know the exact work he did to either prevent it from happening again or just knowing the guts of my bike.

[subsys]

either your mates or that dodgy place on the outside of town (theres always one in every town) run by the permadrunk hells angel type dude ^^

but as gott says if your not sure what your doing (which your not) ask whoever does it if you can watch them while there doing it (possibly explain along the way).

[j0rz]

dont forget to poshish ur in let out let vavles gives a good power boost on 2 strokes and faster throttle response ;)

[virgil caine]

hey guys we are talking about a stock 2 cycle here.
Most likely has stuck rings, thats his complaint no need to go deeper. Pull the jug hone it if you want to and pop a new set of rings in. let her eat karo eat.
At most you would need a cylinder base gasket and a head gasket to complete the job.
Let the flames begin.

[Lexxuk]

My first thoughts on my pistons were stuck/bent/abducted by aliens, cause a few times I lost compression, but a kick or two, got it back, and one time on the way home, i lost power, but managed to get it back eventually. The last time though, compression went totally and wouldnt return, so it was a gradual fault that ended up being terminal, I miss my bike, its summer soon, I want to go run over the tourists :(