By opening up the exhaust and intake a bit... to let the engine breath (and make some RPMs) it will go well above 40. Mine gets to 55 every time I ride it. I'm not telling you it does the 1/4 mile in 4 seconds... it takes a while to wind up but I have had it to 60 on occasion and 55 is a daily occurrence with a bone stock engine with a free flow muffler and a few holes drilled in the air box cover and 14K miles on the clock. Don't believe me? Put some thick money on it and I'll post a video.
This bunk is exactly why I bail from this board, another owner with a stock 50 either capable of a Wheelie or doing 55-60mph or both. and then 150mpg, Im calling bs.. No Knobody believes you because its Impossible. So why don't You Walk Your Talk and post up that Video of You and That Scooter? you should be ecstatic to show us a GY50cc doing 60mph
On a 150 you will be able to pour Gas or Ether directly into the Intake Port with no manifold on and she should pop right off.. Then she will die as the fuel you introduced is used up quickly. Good Luck
Last Edit: Sept 13, 2018 5:56:53 GMT -6 by czmdiver
I'm having the same problem, how did you solve it?
Most Likely Adjust your Valve Lash, They get Tighter Not Looser, when you get to darn near zero lash and you hit wide open the engine gets to maximum operating temperature and things expand, now the Zero Lash is actually hanging the Valve Open and the Scooter dies or bogs down until the engine cools back to some or zero lash and the issue is repeated. There many grate video tutorials.
What kinda Scooter do you have? How many miles on the Scoot? Are you verifying you have Spark when she quits? Have you checked the gas cap vent if it supposed to have one? Have you or anyones else ever adjusted the Valves?
Last Edit: Aug 9, 2018 15:13:16 GMT -6 by czmdiver
What kind of Scooter? 50cc? 150cc? or ? two stroke? Home many miles on her? Are you verifying you have Spark after it dies? Have you checked the Gas cap vent? pop the cap and try it. Have you ever adjusted the Valves?
Last Edit: Aug 9, 2018 15:12:19 GMT -6 by czmdiver