ok here's my promblem, i have a 01 trailblazer 250 that needs new cyclinder rings. i just dont know what i am doing. is it posable to do this with the engine still in the frame....... so far i have the top of the engine off and stoped there. i know i have to measure the cyclinder wall but i dont know the name of the tool i need to do that. so if there is anybody in here that can walk me through this i will give you my first born(just kidding).

 

Easy way to check: stuff rags around rod,remove one circlip from piston,have someone hold piston and knock out piston pin and remove ,dont forget upper bearing. INSERT piston in cylinder without rings on from BOTTOM,hold tight against one side of cylinder,check clearance with feeler guage,IF over .004 clearance,Time to rebore. Or if cylinder scored! re ringing usually not practical on 2-strokes unless fairly new and NOT more than .002 piston to cylinder clearance,WONT LAST! NOT necessary to purchase costly micrometers like I have. I have my SON and GRAND DAUGHTER,you can keep your first born! Good luck

 

You can do this on your own, it's no big deal at all. You don't have to take the rest of the engine out, either. You should probably just buy a new piston kit instead of replacing rings on a 2 stroke (or a 4 stroke IMO). Bore and hone your cylinder .50mm (.020 over), assemble the piston kit (put the rings on and one circlip), carefully compress the rings with your hand if you don't have a ring compressor and slide it into the cylinder, then attach the rod, bolt everything down, and you're done. Don't forget to follow a good break in regime or you'll be doing the same thing all over again soon. Hope this helps. If you need a good deal on a high performance or stock replacement aftermarket piston, send me an IM.

 

ok thanks, but i dont want to sound like a dumb a--. but i'm getting is that i can do this with the engine still in the atv? so do i get to the piston by removing the pull start? or were the drive belt is? i'm sorry but you guys must think i'm a retard, i just never done anything like this before, and atc250 i will IM you when i figure out what i need...........thanks alot

 

No need to remove the recoil or clutch housing.

Sounds like you have the cylinder head off already? Now you need to remove the cylinder. First, remove the carb, just loosen the clamp on the rubber boot on the cylinder side and wiggle the carb loose and free. Now remove the exhaust off the cylinder head. Make sure everything is free and clear of the cylinder. Now pull the 4 nuts holding the cylinder to the crankcase.

Once that's done you'll be able to slide the cylinder up and off the piston. Have CLEAN dry rags handy so you can stuff one around the connecting rod. This will prevent any dirt from entering the crankcase. I also like to stuff one in the carb for the same reason.

Now you have to remove the old piston from the connecting rod. Remove one of the clips and slide the piston pin out. The piston should now lift off the connecting rod.

Next do what the other have said, measure your clearance. If your good, reassemble...if not, have it bored out and reassemble. I'd definitly buy a new head gasket and cylinder gasket if you havn't done so already.

Don't rush, lose bolts/nuts. Take your time. It's pretty easy.

Here's is a link that will help you understand what exactly we're talking about. It's the schematics to your bike.

http://www.bikebandit.com/hous...a25-ca-cb-2001/o/m5579

 

thank you so much. that doesnt sound hard to do at all. and the pics help alot to.

 

ok. i got it all apart. the only thing i have is a spark plug gaper. and i can slide a .008 and a .010 and they both feel about the same. should i just take it in and have it bored out .020 over?

 

I would have it bored if you have that much clearance. If you don't, the fix won't last long. Better off to do it right. Bore it, buy the correct piston and gasket kits and reassemble. Relatively cheap and easy.