Anyone know about this superfreak?

[G-Body]

Well it`s been interesting so far. The PSI Genesis 1085 stroker seems to be really rare, I did find that there might have been a rider or 2 in France that tried one. I pulled mine down and found out that this motor was unfired, looks like they were setting the quench and just stopped working on it. Being that it was so rare and is missing the lower piston rings I was thinking of tossing in a 701 and running that.....turns out the mounts were set in this hull are not put in at yamaha spacing. I`m assuming that this is polaris spacing, but the bed plate that I have with the PSI motor is either fiberglass or carbon so maybe it`s polaris spacing maybe it isn`t. But looking at the hull there`s no marks from grinding old mounts out so I think these are original. I wasn`t expecting that, I figured someone just made a bedplate to adapt to yamaha mounts.

 

[OtherDonnieGuy]

Well it`s been interesting so far. The PSI Genesis 1085 stroker seems to be really rare, I did find that there might have been a rider or 2 in France that tried one. I pulled mine down and found out that this motor was unfired, looks like they were setting the quench and just stopped working on it. Being that it was so rare and is missing the lower piston rings I was thinking of tossing in a 701 and running that.....turns out the mounts were set in this hull are not put in at yamaha spacing. I`m assuming that this is polaris spacing, but the bed plate that I have with the PSI motor is either fiberglass or carbon so maybe it`s polaris spacing maybe it isn`t. But looking at the hull there`s no marks from grinding old mounts out so I think these are original. I wasn`t expecting that, I figured someone just made a bedplate to adapt to yamaha mounts.

have you measured bore and stroke? Looks like it has the correct PSI casted cases for those cylinders, and with cylinders having triple boost port it could be a 995, 1010 or 1085?. What you likely have a snowmobile motor that has been converted with a watercraft crank. The powervalve blanks are likely set up to drop exhaust port timing. Also no base gasket to decrease time area.

I would compare your engine cradle vs a Polaris octane cradle. That should give you the answer your looking for. Then putting a Yamaha motor in should be same process as doing 701 in an octane hull.

 

[Fro Diesel]

Ahhhhhh I tem.ember hearing about that ski.
That thing is a unicorn amongst unicorns.
By quench do you mean squish? Pardon my interruptions.

 

[G-Body]

@OtherDonnieGuy Its a 1085, 1085 is stamped into the side of the cylinder just above the base gasket area. It`s 98mm pistons and 76mm or 78mm stroke, I can`t remember which was stamped into the crankshaft and somehow I missed getting pics of that while I had it apart. It was setup with multiple thicknesses of shims for under the cylinder, I have all the way from 1.xxmm to over a 3mm shim. There is a base gasket in the spare parts, but it was not installed. There was also the remnants of a destroyed base gasket in the pile. The powervalves are the only part of the motor that appear to have been run. I don`t have a polaris cradle to compare to, but I`m not too worried. Being that it looks like this freak was setup to run a polaris engine from the start I might just put this unicorn motor the rest of the way together and send it. I could just make a new set of bed plates to hold a 61x on these mounts, I was just hoping everything would bolt in....guess I should know better when working on a freak.

@Fro Diesel what did you hear about this one? I knew someone had to know something about this ski, too many trick parts for it to be a complete secret. Yeah I meant squish, guess it was a long day yesterday.

 

[OtherDonnieGuy]

@G-Body , if you get free time could you measure the cylinder spacing of that motor for me? I would like to add it to my notes. Curious if they used the same spacing as the others with PSI cases I have gotten measurements from.

 

[G-Body]

Yeah I sure can. Are you just looking for a center to center bore spacing? Or are there other measurements? I`ll post the bolt torque values as well if I can get them, I know approximately what they were tightened to when I started, but I still want to try and find someone who knows what they should be. I just found out yesterday that it appears this motor used honda CR500 rods.