Well,
I don´t know the number in the carburator, but I know that I must increase it, becouse, the entrance is 1/2 in., but I don´t know in the venturi...I feel that it´s small...I must to put a Walbro WT-433
I test it with a wood 20x8, APC 18x6 and a APC 18x8
With the 20x8 gets 4700rpm
the 18x6 --- 7000rpm
and with the 18x8 6700rpm
Originally the muffler was one 8mm exit, but I welded another tube with a 10mm internal diameter (you can see in the pics how I burned the paint), and the rpm go ups (500rpm)
Thank you for your intererst.

Good flights

Sergio

[email protected]


PD: sorry for my english, I´m from Argentina.