Originally Posted by mkatt4x4
From reading tons of threads on this forum, it seems a lot of motorized bicycle enthusiasts go through many engines. Which makes me wonder if the kits are $170'ish and the engine is $100'ish, whats the range for the GRUBEE SkyHawk GT5A 66cc Angle Fire Slant Head Bike Motor before it dies, with normal use....of course. And is there anything else recommended to upgrade on this kit, to make it more reliable and last longer?
i had a grubee gt5 before my dax race motor.... i spent over3 weeks trying to blow it up !!!! it never siezed !!!! i ran that like motor you never saw motor run before !!! i even heald the throttle wide open in nuetral no load for a good min every day trying to see if i could sieze it !! i would pourposly rid as hard as possable reving it up wide open all the time and holding it there, pulling the clutch in wile rideing at wide open throttle and letting the motor wind out then dumping the clutch and repeteing this over and over, long burn outs on the concrete, super high rpm down hill riding, reving it as high as possable to see if it would blow, i even ran it on a 50/50 mix of rubbing alcahaul and gasoline mixed 70 to1 and reved the crap out of it wile riding as hard as i could for 2 days on that mix and the only thing that happend was she ran a little hot ! finaly i ran it on strait gas with about 25% acetone added in and rode it 5 mile to work !!!! i cant believe it made it like that !!!!! on the way home though it over heated and slowly siezed going up hill 1 mile from my house so i pedaled home.....lol........... before i removed the motor i was riding the bike around adjusting the rear hub for free play and i dumped the clutch on acsident ..... to my suprize she turned over and wanted to start !!! W.T.F......!!! some how it unfroze itself !!!!
apon tear down of the engine, i saw the cylinder was severly scored and scratched and the piston dome was blue from over heating and scraped up bad on the skirt, the rings were worn so bad they were rounded out LOL and shiney !! the chrome was flaked off the jug to the tune of 30% of it missing and the play in the needle bearing was real flopy and loose....
but even with all that castostrofic damage to the top end and running on cheap gas mixed with acetone and no oil ..... it still wanted to start back up !!!!!!!
this changed my mind on the china girl and this incident is what made me go for another 2 stroke rather than use the 4 stroke i had planned, it would appear that as long as you have a well tunned carb your motor will take a serious beating !!