Recent posts by kubi11 | Scooter Doc Forum

4 Valve Head or a Big 2 Valve Head by: kubi11 - Apr 4, 2024 13:38:24 GMT -6 via mobile

Reply Quote

Post by kubi11 on Apr 4, 2024 13:38:24 GMT -6

May 26, 2015 21:26:09 GMT -6 jct842 said:

I would go with a 4 valve on the gy6. I also believe one of the biggest boost is making that engine breath. The head, intake and output of it.

Most of the small jap engines today make more than one hp per cubic inch and the big difference is breathing.

A stock 150cc makes about 9hp, with the same compression a majesty makes 34 for a 400cc engine with 4 valves. 6 hp per 100cc on a gy6, and a majesty makes 8.5 per 100cc.

Well i have 161qmk 171cc 12hp 2 valve scooter and im wining against yamaha aerox 155cc 4valves 15.5hp even if the driver is lighter in weight for 10kgs 🤷‍♀️
Wanted to upgrade to 4 valves but changed my mind after that

even aprilia sr160 cant hold up with its 3 valves

also mine is fuel injected

Recent Posts By (Read times)

Post by kubi11 on Apr 4, 2024 13:38:24 GMT -6

Shoutbox