I need advice on a new piston 20 over for new cylinder.

[BMH]

I am going to buy a clyinder and head for for my 1990 K5 form a cart racer. He says it is 20 over what piston should I buy. I am going to rebuild the top end myself for the first time. I Have done alot of wrenching mostly 4 strokes. I am not sure of all the measurements.

[Watercross]

Ask if it is sleeved,  I have seen/read of many sleeves that are installed incorrectly and the sleeve drops or shifts when the motor heats and causes a head gasket leak. Im sure one of the big guns on here has more info to share, I would wanna make sure that the sleeve done by a Rep. shop and that he has had zero issues thus far. Those are just my thoughts. -Watercross

[RoostDaddy]

Water,  20 over wouldnt be the last overbore.  Thats only like .5mm not 2mm (80 over would be the 88mm)

BMH,  I'd wait until you get it to see what the cylinder looks like before you buy a piston.  If its in good shape you could just give it a hone and put the same size piston back in, if not you can bore it and put a bigger one in.  (that is, if it is sleeved)

[Watercross]

LOL you are right, sorry about that. Point I was making was about the sleeve, My buddy and I went through that, just given something to consider or ask.

[BMH]

I just picked up the cylinder its is sleaved done by LA sleeve. It looks good just needs a hone and cleaned up. I also got 2 heads with it 1 good shape 1 descent. al for $125.00. I am going to take it to a machine shop and have the bore measured just to be sure. I should be back riding soon! anyone got a manual for sale?

[RM_Rider14]

I just picked up the cylinder its is sleaved done by LA sleeve. It looks good just needs a hone and cleaned up. I also got 2 heads with it 1 good shape 1 descent. al for $125.00. I am going to take it to a machine shop and have the bore measured just to be sure. I should be back riding soon! anyone got a manual for sale?

Done by LA Sleeve, or it has a LA Sleeve in it?  I had a LA Sleeve in my YZ 250.

[BMH]

I Took the new cylinder to the local machine shop (trusted) To have the bore measured good thing there was some descrepencies in the bore sooo its is sleaved and I am having it bored and honed. I am glad I didnt take the guys(seller) advice and just order a piston. Now it will be right and tight, the bottom line the old girl will roar again thru I :-Ddaho YES!