Re: How durable are these engines?? 66cc
well i had this same question and......... just let me tell you if you buy it and bolt it on your going to be disapointed !!!!
there are things that NEED TO BE DONE!!!!
first take the whole top end off and port and polish the intake and exhaust nothing big time just clean up the garbage they sent you.
then port match the intake and exhaust header as best you can
tune the carb as best you can be shure to buy a kit with a carb that is tunable
now pull the gutts out of the stock muffler and drill out the stinger pipe to 1/2 ID
sand or deck down the head a lot !lol
cut the piston skirt where it blocks the intake at TDC ... believ me it will !!! mine covered almost half the intake !!!!!
next forget about the 16:1 ratio they tell you and toss the oil they gave you in the garbage ! go get some full synthetic and break it in at 32:1 and runn it at 40:1.
you now have a bike motor that will run way better and be more efficiant that stock aso it will pull MUTCH harder up hill just by doing nothing but modifing the stock parts correctly
none of the china motors are good out the box but some will run fine some wont. i know if i ran mine stock it would have blown in a week !