I have been working on my grandson's LG50, Alpha Sports. It wont run after about 10 minutes of riding. I have disconnected the exhaust and seems to cure the problem. My question is, how to clean the exhaust. It seems like it doesn't have any restriction when you blow through it, but maybe it does when it heats up. Any suggestions would be appreciated.

 

I stick them in a fire/charcoal/etc. to get them red hot and blow compressed air thru.

 

Plug one end and pour HOT soapy water in and shake. Use a good grease cutting soap. Repeat a few times and flush, let dry.
If the chambers are big enough you can drop a few nuts and bolts in the mix and shake , knocks the carbon loose. Just remember to count your nuts and bolts so none get left behind .

I found this to work well on snowmobile expansion chambers