My son was riding thru our trails last night and all of sudden the quad started bogging down at full throttle. We shut it off, then started back up fine / idle fine but when I push throttle under load it Boggs down and stalled. Checked for pinched lines and everything looks good. I lifted the back end up so the back tires where off the ground and seems rev up and tires were spinning ok. It’s just under load where it Boggs down and won’t move? What could be causing this all of sudden?

 

Welcome to the forums.
I'd start with a good carb cleaning.

 

 

 

Hope the kiddie has fun.

 

Hey lt80. I have a kolpin 90 and I was wondering the compression specs for the kolpin 90

 

Most motors need freshened if comp is below 90.

 

Do you have any idea were I can find a new top end for the kolpin 90

 

I'm sure that ebay sells $30 junk kits or you can get a oem piston (.5 over) and have the oem cylinder bored to fit the piston. It's more expensive but much more dependable.