Stranded with a seized motor

OrionSphere

Active Member
Local time
8:17 PM
Joined
Feb 19, 2024
Messages
138
Location
Shawnee, OK
I took my PEXMOR 100cc on a 115 mile trip.
Left this morning to go back home and had to pass through some terrible country roads. Just before I got to a relatives house, I was going down a hill and hit some more of those gravel bumps shaped like ripples on water. Caught me by surprise and I didn't clutch like I normally do.

Engine shut off and when I tried to start it the back wheel just locks up. I couldn't take the spark plug off because I didn't bring the socket, so I took off the top. Surprisingly, the rings are fine and there's no scarring on the cylinder. Still not turning over

The chain is not locked up either, so it's not that.

Something messed up with the bottom end? Ideas? My piston coloration is strange on the top but that's about all I see that's wrong with jt.
 
Seems fine to me, ive got the ball and the bearing
1000002426.jpg
1000002429.jpg
 
If the head is off, try pushing it with it off, keeping a hand on the jug so it doesn't pop up, if it runs smooth then it isn't seized or stuck.

Check the clutch side, look for broken teeth or other carnage.
 
I took my PEXMOR 100cc on a 115 mile trip.
Left this morning to go back home and had to pass through some terrible country roads. Just before I got to a relatives house, I was going down a hill and hit some more of those gravel bumps shaped like ripples on water. Caught me by surprise and I didn't clutch like I normally do.

Engine shut off and when I tried to start it the back wheel just locks up. I couldn't take the spark plug off because I didn't bring the socket, so I took off the top. Surprisingly, the rings are fine and there's no scarring on the cylinder. Still not turning over

The chain is not locked up either, so it's not that.

Something messed up with the bottom end? Ideas? My piston coloration is strange on the top but that's about all I see that's wrong with jt.
Just a heads up, Pexmor is the distributor of your 72cc, not a brand or type of engine.

To help you while stranded, do this.

Take off the clutch cover and see if A) The Philips screw in the clutch plate came out and as a result, tightened your plate.

I want you to remove the screw and loosen the crap out of the plate to see if it will move freely. I then want you to lock in your clutch lever, and on the magnet side (as it will be easier) see if you can move the crank by turning the nut. Assuming you have the stock M8 nut on the magnet, it will be a 14mm socket. You can also try this on the small bevel gear.

Try moving the crank manually once the plate is loosened damn near all the way.


Disengaging the clutch allows the crank to move freely without the bike moving, just as disengaging it allows the bike to move freely without moving the crank.
 
If the head is off, try pushing it with it off, keeping a hand on the jug so it doesn't pop up, if it runs smooth then it isn't seized or stuck.

Check the clutch side, look for broken teeth or other carnage.
With head and jug off it won't move, chain moves freely with clutch pulled in, chain looks fine
 
Just a heads up, Pexmor is the distributor of your 72cc, not a brand or type of engine.

To help you while stranded, do this.

Take off the clutch cover and see if A) The Philips screw in the clutch plate came out and as a result, tightened your plate.

I want you to remove the screw and loosen the crap out of the plate to see if it will move freely. I then want you to lock in your clutch lever, and on the magnet side (as it will be easier) see if you can move the crank by turning the nut. Assuming you have the stock M8 nut on the magnet, it will be a 14mm socket. You can also try this on the small bevel gear.

Try moving the crank manually once the plate is loosened damn near all the way.


Disengaging the clutch allows the crank to move freely without the bike moving, just as disengaging it allows the bike to move freely without moving the crank.
Philips screw did not come out. I loosened it and of course it moves freely, but it did before.

It moves with the clutch pulled, just not with the clutch engaged.

This is not moving at all
 

Attachments

  • 17119258973105776568417209785948.jpg
    17119258973105776568417209785948.jpg
    295.5 KB · Views: 32
Back
Top