The pro 81/82 from what ive read is designed for the open 135cc+ motors.that being said does anyone happen to know what degrees the exhaust opens on those engines atdc.i currently have a kbl6 and the way i understand that pipe design is made for a port earlier than 86 degrees.it runs pretty good on the engine on my kart 116cc with a 88 degree atdc exhaust port.i was trying to see what the older exhaust degree timing was bc i was thinking of buying a pro 81/2 pipe for my kart if the older 135cc engine had a exhaust port around that degree..thanks