Crazy Moped gy6 50cc 139qmb Insane head work done

[@cav3man360]

Add the a9 cam ...still stock 50cc love it bro

[@thundercatt5265]

I took the stock engine out and threw a brand new 70 cc piston in this old scooter i had ,i already had a 70 cc cylinder to spare, then i got rebuit a big bore head with some new valves to replace the stock head and then chopped up a 110 cc crotch rocket exhaust that has 2 mufflers on the pipe and added adjustable carburetor...but I got a oil leak...so I gotta patch that up

[@gennygauck4974]

How has this build turned out? I'm doing a similar build

[@evidentloss]

How does taking material away from the combustion chamber add compression? I'm pretty new and must have missed something lol

[@dillonracing8384]

It's to be matched with a custom piston that I make the work in the chamber helps the flow a ton

[@gonewronggarage4565]

Why would you make the port bigger than the valve seat?

[@dillonracing8384]

With all of your testing we found out a 21mm port is the best for a stock valve size we made all most 9hp on a 82cc build but the piston we used is not made any more

[@rallyscoot]

but you used still those small valves? I dont get it.

[@dillonracing8384]

For a 50mm bore or smaller stock valves will always make more power unless you are sparying and full nitrous wet kit

[@hessulinnaify]

No😂😂​@@dillonracing8384

[@rallyscoot]

It doesnt make sense to do such a job, if you can get the right 72cc better head in the store. 50cc and 63cc doesnt require that kind of `tuning`. And such a head doesnt seems to work on everything lower then 72cc.. Because then you loosing compression due to much room in the fuel and exhause channel. I already did ever installed a 72cc head (saying it was for 50cc) on a 50cc cilinder... Then the engine didnt suck fuel on, so didnt want to start or idle. When replacing with a known good stock head, the engine was running again. So opening up (of make bigger channels isnt always the best to do)

[@dillonracing8384]

This works better then those heads it's been made right

[@dillonracing8384]

I have a piston dom that I make to fill the combination chamber