cylinder scoring/scratching

[Toby woodman]

I have a 66cc 2 stroke kit. it has a couple of hours of riderime on it. I was riding uphill when the engine seized. when I got the piston freed up I pulled the cylinder off and I found some deep scratches. when I put the piston back I the engine had compression. would I be alright to keep running this engine because the scratch is below the piston rings. what could cause damage like this?

 

[DieselTech]

I have a 66cc 2 stroke kit. it has a couple of hours of riderime on it. I was riding uphill when the engine seized. when I got the piston freed up I pulled the cylinder off and I found some deep scratches. when I put the piston back I the engine had compression. would I be alright to keep running this engine because the scratch is below the piston rings. what could cause damage like this?

Your piston ring locating pin came out. You are going to need a new piston & cylinder. Also known as a cylinder kit.

 

[ImpulseRocket]

Your piston ring locating pin came out. You are going to need a new piston & cylinder. Also known as a cylinder kit.

Are you certain? I think I can still see it, but the lighting and picture quality make it hard to really determine.

If it is in place then you can keep running it. If it has any sharp edges it would be a good idea to try and lightly sand the sharp bits down. Inspect the cylinder and see if any of the plating came off, or if it has any scratches as well.

As for the seizure, determining the cause is a good idea.

 

[DieselTech]

Are you certain? I think I can still see it, but the lighting and picture quality make it hard to really determine.

If it is in place then you can keep running it. If it has any sharp edges it would be a good idea to try and lightly sand the sharp bits down. Inspect the cylinder and see if any of the plating came off, or if it has any scratches as well.

As for the seizure, determining the cause is a good idea.

I thought it looked missing, but then again I'm just using my phone.

 

[DieselTech]

I have a 66cc 2 stroke kit. it has a couple of hours of riderime on it. I was riding uphill when the engine seized. when I got the piston freed up I pulled the cylinder off and I found some deep scratches. when I put the piston back I the engine had compression. would I be alright to keep running this engine because the scratch is below the piston rings. what could cause damage like this?

Toby if you would take a pic of the intake side of the piston, looking forwards towards the exhaust. We need some pics of piston ring locating pins. Thanks.

 

[Chainlube]

Are you certain? I think I can still see it, but the lighting and picture quality make it hard to really determine.

If it is in place then you can keep running it. If it has any sharp edges it would be a good idea to try and lightly sand the sharp bits down. Inspect the cylinder and see if any of the plating came off, or if it has any scratches as well.

As for the seizure, determining the cause is a good idea.

There are two of them though.

He has to take the engine off the bike and determine if there is anything down inside the case before ever running it again. For the price of a new cylinder kit and the peace of mind, I'd just replace them.

 

[Wrench]

The piston will be fine just sand that scratch smooth by hand, Make sure the ring locating pins are in place
I would worry more about how your cyl boar looks, and if there is any metal floating around in the case

 

[Toby woodman]

the cylinder has no marks. the piston ring locating pins are still there I don't think they come out on my piston (I don't know for sure) I have put the engine back together after taking down some rough edges with some sand paper and it has compression, its hard to tell how much when turning it over with the output sprocket but I will see if it runs later today. does anyone have any idea how to keep piston rings in the right place when installing them as I'm still not sure if they twisted round when I put the piston back in the cylinder

 

[Wrench]

the piston ring locating pins are still there I don't think they come out on my piston (I don't know for sure) I have put the engine back together after taking down some rough edges with some sand paper and it has compression, its hard to tell how much when turning it over with the output sprocket but I will see if it runs later today. does anyone have any idea how to keep piston rings in the right place when installing them as I'm still not sure if they twisted round when I put the piston back in the cylinder

Ya gotta make sure, That's what keeps the rings in place

 

[Toby woodman]

any tips to keep them in place while I put the cylinder on