Review - Beta 300 RX Two-Stroke

“…felt a bit flat on top and lacked the extended pull…”

Unfortunate big bore characteristic

While it depends on the carb. ML made the correct adjustment. I had to look it up.

WUT? Turning the AIR screw in(closing) reduces air making the A/F richer. Less air = more fuel = richer air fuel ratio aka richer 

As I mentioned in the comments on the homepage, how do you get the engine to move the bigger piston faster in the higher rpms (which is the problem with all big bores)? 

PC Works pipe has my 300SX reving further. Bill's pipe is said to have the better pipe.

The reviews can come off like the bikes don't have an easily tunable powerband or suspension, pegs, bars etc... 

Here’s a good article on port window with big bores. It’s related to a 125, but he discusses the port window problem on a big bore (only with no stroker increase). A slight increase in rod length or offset on the crank would completely transform this one (and the KTM in my opinion).

https://www.hpracedevelopment.com/news--articles/a-wicked-fast-yz125-bi…

Here is the excerpt from the BETA RX owner's manual on the carb air mixture screw; "screw #2 adjusts the quantity of which is mixed to the fuel for idling. If the screw is turned counterclockwise, the quantity of air increases (thin mix), if turned clockwise, the quantity of air diminishes (fat mix)."

It is the same as most modern bike carbs. Couliins76 was correct in his thinking.

Mike, could you tell us the exact suspension and carb adjustment settings you ended up at? It is not clear in the video.