BBP wrote:
Quote:
First gen have the transfer cut out way above where they need to be, and are prone to cracking. My personal last choice.
Exactly.........I am wanting to build a more hopped up top end.........like around around 100 HP........pretty well know what I want to do.........the late model cylinders cutaways can be raised a bit to match the Wossners..........and leave plenty of material (liner) between the inlet port and the cutaways........with the First Gen, there is very little metal there........they can and do crack........hate to spend a few grand and have a cylinder crack.........some racers say don't go any more than the 2nd bore oversize........maybe they use the same forging for a piston........they get a bit heavier when running a 790cc 6th size out..........than a stock size 71.5mm
Agreed, if it was a stock H2........the First Gen do make the most power (74 I beleive is what they claimed)............and the ports are oriented differently (more foward)..........those would be the ones to get
Moo did my current B\C cylinders..........stage 1..........I like them a lot and gonna leave them alone the way they are........pristine.....he raised the cutaways just enough to match the Wossners at BDC..........any more cutaway is kind of useless anyways..........as it's covered up by the piston skirt when needed the most..........at least with Wossners it is, I think Wisecos too, not sure about early H2 pistons
THX Phil
Hi Phil.
I am not sure, but I think just looking at the piston cut-offs vs cylinder cut offs to match at bdc is a bit simplified.
This is because you get transfer flow from crankcase long before piston is at bdc, especially With good pipes With great suction. In fact, if good blowdown, the flow starts just after transfers open. At that time, Your piston cut out skirts are same distance from bottom as Your transfer port heights. That means, Your liner cut off should be at same Level as Your piston cut outs just after transfers opening.
At least, I believe that is one of the reasons I have a lot more than 100 rwhp in my H2. One must do everything that can be done to improve transfer flow on a H2 due to the very narrow ducts. (A 500 has a lot better transfer ducts area, much wider due to the smaller bore)
I am running the early square cylinders.
Just my opinion.......
(and the H2 liners With high square cut outs do not break as easy as the H1 liners)
Jørgen
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