Another one of the weird transfer port jobs

[romack991]

noticed this on ebay. another one of those tall "boost" port. was it ever explained what this does for the engine?

http://cgi.ebay.com/ebaymotors/SUPE...tegoryZ56422QQihZ014QQitemZ330019059008QQrdZ1

 

[sflsurfrider]

extra lubrication?

 

[Matt_E]

I talked to Paul about it before and don't remember what he said.
I think it boiled down to more boost port volume.

 

[Freestyleriverrat]

I have a cylinder almsot exactly like that I have been trying to sell. Pistons too. Any takers :biggrin:

 

[waxhead]

I know the seadoo 785 is like that but when you buy aftermarket sleeves they get rid of it
seems that they go better with out the transfer like that

 

[2XLR8]

Thats normally done when the piston is ventilated with a whole that matches that area. The theory is it helps with boost port air flow . I dont think it matters much because the width of the boost port is the limiting factor. On the kawis it could help because their boosts are a lot wider.

 

[SUPERTUNE]

Using a hole machined in the side of piston matched to the port just below the rings aids in keeping the underside of piston crown much cooler. I did lot of them back with mod 650/750 kaws in mod 785 runabout class, made it a bit harder to get jetting right as it muddys the carburetion on the bottom end but motors ran better piston temps and lived.