I would at least recommend a new hone for that thing, I don't see any crosshatching at all. A powersports dealer will do it for $10. If its out of shape, someone could have used a ball hone on it on a drill. A new hone should up the compression a little bit also, especially with a new set of rings. There are alot of scratches in the bore. Do any of them catch your finger nail because you made need a one step bore, but at least a hone. If you did a hone and rings it would be about $40 total to do.

 

If it is out of shape, it could also be from uneven wear from the rings/piston in the cylinder while it was running.

 

Also, I would say a new sleeve was pushed in after the bore and was welded together and the weld is cracking, probably should be re-welded if thats the case.

 

Yeah the cross hatch is all but gone, but it appears the plating is more shiny in some places than others or burnt off in some areas. Is this a nik plated sleeve or cast iron? Because if it's nik you don't have much room to play with when honing. It holds great compression now as is, and I can barley feel a thing with my finger nail in the jug.

 

After a closer inspection there is a slight lip on the top of the cylinder (more on one side than the other) will a hone take this off? Also someone told me to try a magnet to see if it is steel or nikel plated, is this true? It seems to stick to both unless they are both steel sleeves.

 

They both should be magnetic so that wouldn't be right. A hone probably wont take a ring ridge out. A ring lip is caused by excessive wear and use. I'm assuming that thing is probably on stock bore and hasn't been bored out since its first use. What you can probably do is as long as you don't change the rod out or the piston, you could probably buy new rings, get a hone done which is $10, and just only change out the lower rings and keep the top one the same. The reaon I say that is because if you look closely at the top ring, you can probably see its worn down towards the top, that is where the ring was being worn down when it was forming the ring ridge.

 

Also, make sure there is no up and down play in the connecting rod, side to side is fine. Just wondering, does that thing have the stock rod or aftermarket?

 

Thanks for this info man! They actually get $15 for a hone job around this neck of the woods, but when you say lower rings you mean the lower RING right? I will take a close took at that top ring for some rounding.

No vertical play, and I am not sure but I would love to know (any ideas how to tell?) by the way, I have an old KDX80 engine on a go kart and was thinking about putting an aftermarket rod in it when I do the head, are they really worth it over stock? Are they lighter or do they just have more machined holes for oil flow??

No the jug is not stock bore, it's 1mm over (71mm is the bore and I think stock is 70) but what scares me is the uneven wear, I could see if the sleeve wall was thinner on the front or back but it's side to side. I don't remember WHICH side but either the left or the right side is much thinner than the other, is that what my side to side piston/rod play makes up for?

Thanks again

 

yeh, I meant the lower ring. I was thinking of a 4 stroke for the rings. Eneven wear can be caused by side to side movement of the rod, but its necessary for the rod bearing to get oiled and lubed. It can also be caused by the bore and hone not being done straight, causing uneven wear. Not sure what you are planning on doing for your base gasket, but you can make one out of copper, thats what i'm doing for my lt250s quadsport engine, but the base must be flat of the engine and the cylinder. The other thing is, is if you have a ring ridge and you want to replace both rings, you can make a thicker base gasket, but this will lower the compression. Then you can have the head machined lower or you can probably do it yourself and that will re-up the compression.

 

And the two rings are exactly the same right? (Wiseco sells them in sets of 2 assuming they are both the same) as far as the gasket goes it's 2 stroke so the walls are thin on the edges and you need a real good seal for compression so I'm not going to fudge it, I will buy an entire gasket set for the whole engine because it needs them anyway. I really want to split the tranny case because they used gasket maker but I have never split a tranny before so I don't know how complicated it will be to mesh everything back up and such. Don't get me wrong I fudged the crap out of a CR80R last week, used gasket maker on both the top and bottom of a ripped base gasket (let it cure THEN torqued it down) holds decent compression, I also patched a hole in the case under the flywheel (no oil) with some JB weld and a beer can and I must say, worked very well!

Ya know, I have a spare head in my parts that looks better inside (no dings) BUT with my finger on the edge the one that came off the bike feels SLIGHTLY deeper so I am wondering if it was machined already but that would lower my compression not raise it so it does not make sense (maybe my spare is shaved) I would rather pay the $200 to have it replated if it came to it (I think they bore the old one out included in that price) or I even have a spare jug that is stock and not a resleeve but it would need to be replated and there is a nice chunk taken out of the corner of a port I'm not sure is fixable.