I purchased a 350x motor for my 300ex . I wanted to get a bigbore kit . I am looking at the 393 kit from powroll . I wanted to know if anyone had installed this kit and what they thought of it . I also looked at fourstroke tech and they have a 425 kit four a 350x but I would have to assume I would have to modify my cases for this ? thanks for any input .

 

The one common denominator in both engine setups you mentioned are that all of them are a B!+CH to crank,..hot or cold. And the Goki electric start kit that they make for the 86 model is junk on a high compression big bore 350X engine.
I know from first hand experience. Kick starting it will be an entirely new ballgame. You may have a much stronger leg than I do,..I dont know,..but I've worked with motorcyles for nearly 20 years and the only thing worse than kicking over a XR600, is a modified 350X...lol.

Powroll and 4 stroke tech have been around forever and know their stuff on the older engines. I dont know if Tom Carlson of TC Racing is still around but they use to build some of the most powerful 350X engines on the planet. I have used Powroll exclusively for my latest project that will use a 200X engine (Havent decided on a chassis yet). For other engines, I dont really have a favorite. And picking one of the two best at the 350X is a tough call.