86 Tri-z 250 Cylinder Help

[skeez5044]

I bought my 86 Tri-z a few years ago, I was told that it had a fresh top end, but a couple months after buying it, I lost all compression. I can push the kick start down with my hand without any problems. Recently, I pulled the jug off and found that I had apparently melted the piston and rings. The cylinder is not badly scored, and I would like to have it repaired and plated. My problem is that I don't know if the previous owner had the jug bored and sleeved. I had read that if it was sleeved, I can't have it plated. I attached a few picture of the piston and the cylinder, and I am hoping that someone may be able to identify whether or not the cylinder is stock or if a sleeve has been put in. Any advice or insight would be greatly appreciated.

[yaegerb]

Stock bore is 68MM. Have a shop mic it for you and find out what bore it is on. There are some pretty good gouges in that cylinder wall, some meat will have to come off. If its already on a couple overbores I would resleeve it. L.A. Sleeve still sells them. Link below.

http://www.lasleeve.cc/index.cfm?event=product.display&product_ID=983

[Red Rider]

The cylinder is not badly scored, and I would like to have it repaired and plated. My problem is that I don't know if the previous owner had the jug bored and sleeved. I had read that if it was sleeved, I can't have it plated. I attached a few picture of the piston and the cylinder, and I am hoping that someone may be able to identify whether or not the cylinder is stock or if a sleeve has been put in. Any advice or insight would be greatly appreciated.I'm not real familiar with Tri-Z's, but I've always thought they came stock with a steel, borable cylinder liner. I can't tell from your pics if you have a liner or not, so try testing it with a magnet. If it sticks to the inside of the cylinder, you've got a steel liner. What you read is correct, a steel liner does not need to be plated. The plating (Nikasil) process is only done to aluminum cylinders without a steel, borable liner.

[skeez5044]

Thank you both for your responses. I have just been really hoping that I would be able to have the cylinder repaired and plated. I have heard that the heat transfer is terrible with the sleeves. I guess I'll just have to take it a shop and see what they can do. I will test it with a magnet soon. I am also going to try to find out why I overheated it in the first place. I run the fuel mix lean, but I have never run into this problem on my dad's 85 tri-z. I'm not sure if my water pump is not working properly. I had also read somewhere that the thermostats can stick and cause them to overheat. I really don't want to have the same issue again.

[Red Rider]

I have heard that the heat transfer is terrible with the sleeves.I wouldn't say the heat transfer is terrible with a sleeved cylinder, but a non-sleeved cylinder does transfer the heat better.


I am also going to try to find out why I overheated it in the first place. I really don't want to have the same issue again.Excellent idea.