So, I'm replacing the piston and rings in my sons scrambler 50. I don't have the year because it is rubbed off. It is blue and yellow if that helps, I'm assuming they are are all the same. I have found some pistons on ebay, but they look to be over bore. Any idea on stock piston size? Or should I buy the kit with the cylinder and all? Also, I didn't notice when I took it off, but I believe the arrow goes towards the exhaust?

By the way I was having trouble with it staying running after it warmed up and it was bogging down. I did a compression check and it was at 70 psi. I'm not sure how it cranked and ran as much as it did.

I will also block off the oil injection, but will start a new thread for that.

Thanks for any help!

 

Buy the kit! Better than finding an over size piston and having it bored out. All in one package and most are reasonable.Oil injection was never really a problem on these. Never even had to replace one,but anything can happen.http://www.ebay.com/itm/POLARIS-SCRAMBLER-50-CYLINDER-PISTON-GASKET-TOP-END-KIT-SET-2001-2003-/380703375740?pt=Motors_ATV_Parts_Accessories&hash=item58a3b0817c&vxp=mtr
OEM Polaris cylinder alone is 60 bucks on ebay..http://www.ebay.com/itm/Polaris-0450006-Cylinder-Scrambler-50-2001-03-NEW-/281155405774?pt=Motorcycles_Parts_Accessories&hash=item41762b07ce&vxp=mtr

 

ok thanks for that... Did some more investigating and it turns out the the black rubber crankcase duct that goes from on side of the crankcase to the other is dry rotted and has a 4 inch long crack in it...I'm thinking this was my problem to begin with, not sure cause I'm not really a mechanic. Might as well replace everything while its apart.

 

I just installed that same piston kit on my predator 90 and it seems to be fine. It only has an hour or so on it so we shall see.

Yes the arrow on the piston points down.