top end rebuild

[98blaster]

Oh yes, very free! But do not kick it you can do damage, rotate the crank by hand.

The bearings are possibly shot!

Yeah i suppose i didnt say that in terms that that include adding in common sense.
Use the kicker hold the piston up with you hand an slowly move kicker down to see if all moved freely, dont jump on an actually kick it, all Hell with break loose if you do

 

[Billy]

This is what happened. I bought it extremely cheap, when I bought it the kicker wouldnt move. After a while I got the kicker to start kicking pretty freely. I took the top end apart. Was told it looked pretty good so I put it back together. It kicked fine every time until once it actually started for about 2-3 seconds. Then it died and the kick starter was extremely hard to move again. When the top end was off the kicker moved easy as pie and it moved the piston and everything as it should

 

[speedyslyder]

take it apart again..is there any damage on the connecting rod? or metal shavings? also check to see if a magnet on flywheel came loose and hit the stator...left side by foot shifter plastic piece..check the connecting rod for up n down play if it has any at all it need to be rebuilt or replaced...those engine videos awk posted say it all take you engine apart follow vids and inspect everything.. report findings,or post some pics of your disassemble and re assemble..

 

[Billy]

This is what happened. I bought it extremely cheap, when I bought it the kicker wouldnt move. After a while I got the kicker to start kicking pretty freely. I took the top end apart. Was told it looked pretty good so I put it back together. It kicked fine every time until once it actually started for about 2-3 seconds. Then it died and the kick starter was extremely hard to move again. When the top end was off the kicker moved easy as pie and it moved the piston and everything as it should

take it apart again..is there any damage on the connecting rod? or metal shavings? also check to see if a magnet on flywheel came loose and hit the stator...left side by foot shifter plastic piece..check the connecting rod for up n down play if it has any at all it need to be rebuilt or replaced...those engine videos awk posted say it all take you engine apart follow vids and inspect everything.. report findings,or post some pics of your disassemble and re assemble..

Thanks for the input everyone. As soon as I return from vacation I'm gonna dive into this project.

 

[Larry's Shee]

Take stator cover off and try turning it by hand with the flywheel. If it's free, problem is kicker, if not crank or piston.

 

[Blaaster]

There are a few things that could have caused your problem.

If the bottom end ran freely before you put it together, I would suspect piston seizure.

Did you use sufficient oil to coat the wear surfaces prior to assembly?

If you run oil injection, did you bleed it or make sure that is was working?

Did you make sure that the piston circlips were in correctly and aligned correctly?

As it has again locked up, you will have to remove the top end to investigate, post up a pic of the piston for comments.

You stated that you were told that the piston looked pretty good, how did it look to you?

What qualifications did your friend have?

Was the bore examined for aluminium deposits from piston scuff?

There are other things that would stop the engine revolving, one thing is a loose flywheel.

 

[Billy]

There are a few things that could have caused your problem.

If the bottom end ran freely before you put it together, I would suspect piston seizure.

Did you use sufficient oil to coat the wear surfaces prior to assembly?

If you run oil injection, did you bleed it or make sure that is was working?

Did you make sure that the piston circlips were in correctly and aligned correctly?

As it has again locked up, you will have to remove the top end to investigate, post up a pic of the piston for comments.

You stated that you were told that the piston looked pretty good, how did it look to you?

What qualifications did your friend have?

Was the bore examined for aluminium deposits from piston scuff?

There are other things that would stop the engine revolving, one thing is a loose flywheel.

New to the 2 stroke game. I've been a 4 stroke guy but I'm getting into 2 strokes. The piston is black on top but other than that looks almost new. The cylinder looked good. No discoloration or scratches that I could see. I'm just wondering if the rings being upside down could cause it to sieze like that. Is that possible?

 

[Billy]

There are a few things that could have caused your problem.

If the bottom end ran freely before you put it together, I would suspect piston seizure.

Did you use sufficient oil to coat the wear surfaces prior to assembly?

If you run oil injection, did you bleed it or make sure that is was working?

Did you make sure that the piston circlips were in correctly and aligned correctly?

As it has again locked up, you will have to remove the top end to investigate, post up a pic of the piston for comments.

You stated that you were told that the piston looked pretty good, how did it look to you?

What qualifications did your friend have?

Was the bore examined for aluminium deposits from piston scuff?

There are other things that would stop the engine revolving, one thing is a loose flywheel.

If I take the top end apart and the kicker moves freely, is it safe to assume the crank is good and it was probably just the piston?

 

[Billy]

There are a few things that could have caused your problem.

If the bottom end ran freely before you put it together, I would suspect piston seizure.

Did you use sufficient oil to coat the wear surfaces prior to assembly?

If you run oil injection, did you bleed it or make sure that is was working?

Did you make sure that the piston circlips were in correctly and aligned correctly?

As it has again locked up, you will have to remove the top end to investigate, post up a pic of the piston for comments.

You stated that you were told that the piston looked pretty good, how did it look to you?

What qualifications did your friend have?

Was the bore examined for aluminium deposits from piston scuff?

There are other things that would stop the engine revolving, one thing is a loose flywheel.

Sorry, one more question. How loose should the rings be on the piston. Should they be pretty snug on it or have some play?

 

[Blaaster]

Firstly, the rings should be free with no restrictions, but without excessive play.

Take a look at this pic, if you installed rings of this type, you would have had a very time to get them to fit into the cylinder.

If you did actually get them to go in, think about what expansion would do.

I would expect them to expand and seize.

Did you put the piston in facing with the arrow to the exhaust port?

Did you use new circlips?

You are going to have to take the cylinder off and check for your self.

Please report back with findings.

 

[Billy]

Firstly, the rings should be free with no restrictions, but without excessive play.

Take a look at this pic, if you installed rings of this type, you would have had a very time to get them to fit into the cylinder.

If you did actually get them to go in, think about what expansion would do.View attachment 10214

I would expect them to expand and seize.

Did you put the piston in facing with the arrow to the exhaust port?

Did you use new circlips?

You are going to have to take the cylinder off and check for your self.

Please report back with findings.

I took the top end off the motor and the kicker is still stuck. I'm guessing the crank?

 

[98blaster]

Pull the clutch cover an see if you see any thing broke in there, pull clutch apart an pull basket, that will allow the crank to be free from everything in the engine but the balance shaft