anyone have info in this engine setup

[Goose]

I read somewhere that someone can set yamaha cylinders up to run 91mm pistons with a stock stroke.is this BS or can it be done if so who makes the sleeves to build this engine and are they using seadoo pistons.thanks

 

[njfl]

ADA's new billet cylinder allows running 91mm pistons, but the cylinder height makes it such that it is set up for at least a 5mm stroke.

Full Throttle did a stock stroke 91mm Lamey and I think it is the one that Ant Burgess was running at World Finals.

Yes, the typically piston that they all would use is a Seadoo 951 overbore.

 

[Matt_E]

A stock 61x cylinder is going to be gasping for air at those bore diameters.

 

[SuperJETT]

I know a certain engine builder that tested with 88 and 90mm bores, but I don't think it went much further than testing.

 

[Goose]

I have a 62t 760 cylinder i pulled the sleeves out of and was thinkin about doing a little playing around with any contacts

 

[SkiDaddy]

Sort of on subject, does someone make pistons larger than 86mm (for a big bore already at 86mm)? If so, how big could a resleeved 61X be punched out?

 

[SUPERTUNE]

Joe, If Ant Burgess was on a stock stroke crank the biggest he LEGALLY could run is 86.5mm bore X 68mm stroke would be 799.2 cc's for the class limit of 800cc's
88mm bore = 827.1 cc's
91mm= 884.5cc's

 

[Big Kahuna]

He is referring to Pro Freestyle, Ant would be be legal, under 1000 cc's

 

[Freestyleriverrat]

I thought the boat that ANT ran in Pro Freestyle was a 10mm stroker w/a lamey cylinder.

 

[Mile9c1]

I didn't think he got that till after WF's. Really I have no idea though.

 

[njfl]

Joe, If Ant Burgess was on a stock stroke crank the biggest he LEGALLY could run is 86.5mm bore X 68mm stroke would be 799.2 cc's for the class limit of 800cc's
88mm bore = 827.1 cc's
91mm= 884.5cc's

I was referring to the one Ant ran in Pro class. I thought it was a stock stroke, but like Freestyleriverrat said, it was likely a 10mm.