Clutch/engine seized cylinder head won’t come off

[Toby woodman]

I have a new 66cc engine kit. While I was riding it, the engine started clicking and then Stalled. When I tried to re start it, the clutch started slipping. I have cleaned and de greased the clutch pads and adjusted it but it still slips and the engine won’t turn over. When I go to take the cylinder head off, only the main cylinder wall will come off. Help would be appreciated. If you have any questions ask and I can also send more photos. Thanks

 

[Toby woodman]

With the pic you provided, the clutch doesn't seem to be correctly adjusted as the flower nut is not locked into place with the set screw that I previously mentioned must be in place so as not to back off resulting in clutch slippage.

The protrusions on the flower nut are also covering the set screw holes.

I took that photo before I was finished adjusting. The screw was put back in with the flower nut in the right position

 

[Toby woodman]

According to the picture, there also appears to be quite amount of cable slack...that spring should be tight up against that screw/nut type cable housing hole that the cable is snaked through in order to get to the clutch actuating arm...I see slackend cable showing without the spring with any tension at all against that housing.

I think that might be the camera angle. The clutch still works properly now l. I think the engine has seized. I though the engine would last more than a few hours of run time

 

[Toby woodman]

Yeah looking at that I'm wondering now if the clutch pin fell partially out of clutch shaft & locked up against the engine case. If that's possible. But it dont explain why the cylinder wont pull off if thats the case.

I’m not sure what you mean by clutch pin and where that is. When I took the main cylinder part out. The piston was stuck to the walls of the cylinder but the shaft coming off the piston could still be moved Turning the clutch over. Could oil have made its way past the piston causing the clutch to slip and the engine to seize from friction or cylinder scoring( perhaps due to defects in the casting of intake/exhaust ports)

 

[DieselTech]

I’m not sure what you mean by clutch pin and where that is. When I took the main cylinder part out. The piston was stuck to the walls of the cylinder but the shaft coming off the piston could still be moved Turning the clutch over. Could oil have made its way past the piston causing the clutch to slip and the engine to seize from friction or cylinder scoring( perhaps due to defects in the casting of intake/exhaust ports)

Well if it's a 2 piece cylinder then remove the cylinder head & take a few pics of the cylinder bore. Yes it very well could of had casting flaws & seized the piston to cylinder. What gas/oil mix ratio are you using?

 

[Toby woodman]

Well if it's a 2 piece cylinder then remove the cylinder head & take a few pics of the cylinder bore. Yes it very well could have had casting flaws & seized the piston to cylinder. What gas/oil mix ratio are you using?

16:1 and have just finished running in 2 tanks. I know running this amount of oil can foul the plug but I wanted to break it in properly. I tried to take the cylinder head off but it is seized on

 

[DieselTech]

16:1 and have just finished running in 2 tanks. I know running this amount of oil can foul the plug but I wanted to break it in properly. I tried to take the cylinder head off but it is seized on

Can you get use some better pics of the cylinder & head? So maybe we can diagnose better. More that likely it's going to need a new piston & cylinder. But if it's a 2 piece cylinder, a cylinder & a separate head it should pop loose.

 

[Toby woodman]

Can you get use some better pics of the cylinder & head? So maybe we can diagnose better. More that likely it's going to need a new piston & cylinder. But if it's a 2 piece cylinder, a cylinder & a separate head it should pop loose.

In that case I will send it back. I have enough mechanical knowledge to strip the engine down and was expecting to have to do so after a year or so but when this is a new engine it’s a bit disappointing

 

[DieselTech]

In that case I will send it back. I have enough mechanical knowledge to strip the engine down and was expecting to have to do so after a year or so but when this is a new engine it’s a bit disappointing

If you think they will warranty the engine, I say do that. But if they wont warranty, you might have to do a top end rebuild.

 

[Toby woodman]

If you think they will warranty the engine, I say do that. But if they wont warranty, you might have to do a top end rebuild.

Thanks for the help. I would be surprised if they didn’t warranty the engine it’s basically new one quick question. The only mod I have done to the engine was to take the cap off the exhaust. Would that cause a failure like this?

 

[DieselTech]

Thanks for the help. I would be surprised if they didn’t warranty the engine it’s basically new one quick question. The only mod I have done to the engine was to take the cap off the exhaust. Would that cause a failure like this?

Yes I imagine it would run real lean without the muffler cap.