That's why I asked about plug color...if the exhaust was plugged it wouldn't run for **** and it'd have poor combustion. If the plug is white/white then combustion temps are too high and there is a fuel/air delivery issue. I watched the video and when off the throttle is made the rattle, but when on the throttle it went away...at least that's what I heard in the video.


I'd be curious if it makes the same level of noise with the intended load on the motor (the child)...


If there is an issue you'd clearly see it on the exhaust side of the piston if you pull it apart...


From what I've read less than 400 degrees is fine if the reading is taken after a decent load is placed on the motor...it should go down at idle.


I'm doubtful that noise is cylinder related...when a 2-stroke goes...it usually just goes...

 

ill pull it apart and check the ring end gap again, it heats right up to 300F idleing so something is strange

 

I'm not worried about ring gap. I'm wondering the condition of the piston and cyl wall.
I know it was just bored but..

 

Can't tell from the vid, but were those head/cylinder fins ever coated (like powder coat)? While PC will make it look much better, it's a thick coating that will trap heat...just a thought...

 

yes 3 coats of bbq paint. hmm, that is food for thought- I have a feeling they bored it with to little piston to cylinder clearance- ran it today with temps well below freezing, no noises so I did a longer spin around the driveway (like only 1000 more feet) and it started making that noise about 50 feet away from the house, it locked up as soon as I let off the throttle.

 

locked up as in seized??


I PC'd my motor but left the cylinder alone...air cooled machines rely on that heat transfer...I'd strip the paint if I were you...

 

yup, noise started and I thought oh what the F and tried to make it another 50 feet, let off the throttle and it instantly died- was able to pull it threw immediately after though, I'm positive its grabbing the skirts- I will pull it apart and post videos. Maybe the previous owner played with the timing? THe factory paint was burnt off the cylinder as it ran hot even before I rebuilt it.

 

There is no paint on a factory cylinder/head.
Like I said, pull the head and see what the piston/cyl looks like now. Sounds like it's sticking.