ESR big bore

[rjt500r]

I guess that is really my question , is this package setup dialed in off the shelf or does it need tweaked for it's full potential? The ESR site calls the setup" 4- stroke killer" with pipe and porting options and the +5mm crank, carb, power valve, reed valve. Arlan and I talked about the ESR 350cc, but he also showed me some dyno numbers for the Puma 408cc.

I should have said be careful with the extra stroke on 'ESR' cylinders, they were normally cast for stock stroke.  I have heard that the cylinder you get for a 330 trx9 will be the same as the one you get for the 330 +4mil or 344, which would put the port timing higher on the 344.  I had a K&T built 344 that had too much timing and not enough bottom end grunt.  I was told by Arlen and others that it was because it was due to the extra stroke.  Don't get me wrong, it "killed" some 4 strokes, but it wasn't much fun to ride. If you go ESR, and you want the extra stroke, make sure it's one of the cylinders that he cast long in order to do it right.

The spynx and puma cylinders are cast such that they can match either stroke no problem.[/QUOTE]

Thanks , time to sell one of my R's and fund the Puma build.

[Pumashine]

Thanks for the info, it seems no matter what i have i want a little more power, i thought my Zilla ran pretty hard until i had Jerry Hall port the cylinder, big improvement, really happy with Jerry's work. Honestly the Puma is what i want, just a little cautious about going too big and having reliability issues.

The only problem in the last six years on the Puma was the tins coming off the Hotrods +4mil crank we were all using in the beginning. Since then all my 400+cc motors have the tins welded in place.