Octane Yamaha engine swap in the works!

[cjbchopper]

After much thought, I decided to go with a big bore Yamaha mill in my Octane. I have enjoyed running the Polaris motor, but I am ready to shave some weight and get some more low end punch. Figured I would post my build pics to keep the Octane section going. My foam was wet, so I gutted the tray. Going to do like "Ryan" and move the motor mount plates in a couple inches and run the Yam engine cradle. Any input from others who have done this swap would be appreciated!!

 

[ryan]

yeah buddie!!!

 

[madness maker]

nice! i had the same idea of doing the big block yamaha in mine,glad to see someone doing one.. mine runs good with a fresh motor for now..i'll be watching.. also, from where do they leak water into the tray? im about to put some footholds in mine and im afraid of what i'll find..wanna try and fix the leaking issues before i refoam and it gets wet again.. thanks for any info.

 

[ryan]

just about everywhere.ride plate bolts, pump bolts ,bulkhead,cooling tubes. where you ride out of?

 

[MADMAT]

Ryan...is they your Yami powered octane I rode in NY!? LOOOOOVED that thing!

 

[ryan]

no i wish its not done yet. havent worked on it. i have ben riding my fixsteer every free min i get before its to cold. i think its over now so i should get back to the octane soon.

 

[MADMAT]

Well I rode one at the NY ride and fell in love! Yamaha power on a solas pump (I think it was??).......it handled really good and I felt like I was on a aftermarket hull. I wonder if it feels the same to just widen the rails on SJ's like some people are doing?

 

[Weber guy]

If you gut the foam, remove all the inserts and grind off all the "green glue".
It needs to be updated with a better adhesive, thats why they all leak. I personally use West Systems epoxy or the Six-10 stuff, but there are tons of good epoxies out there.

Whats your favorite? I like Epoxies, as it adheres to Polyvinyl & Polyester resin. (the Green glue does not)..
Fill the inside of the tray with water after re-glueing everything and check for leaks. Some Octane's leak at the bond flange also, between the top & bottom deck.

The Superjet fuel tank is slightly smaller than the Octane tank, and gives a bit more room.

Regards,
Randy

 

[speedysprocket]

I refoamed my Octane after resealing every through hull fitting under the tray, and it still leaks... I have the Watcon drain plugs in there and open them after every ride to let the water drain out.
What's wrong with the Octane engine? I just put 46 Novis on mine and it's pretty awesome! I'm looking into rebuilding the motor over the winter with porting and hopefully some power valve snow mobile cylinders...!

 

[cjbchopper]

I love the Polaris motors top end pull. I was running dual 46 SBN's, snowmobile head, Boyensen reeds, and watcon CDI. The motor made great mid and top end power, but I want the hit of a big bore Yam. Plus, I weighed my Octane motor, and weighed a Yamaha, almost a 25# weight difference. On top of that, the big thing I needed to make the Polaris motor hit is at MSD TL. I have looked for one, can't find it. Also, I have smoked 2 CDI boxes in this ski over 4 years. I had to buy them both new $$$....Just several of the reasons I want to swap it. Lastly, the last reason....I was riding my octane with the Polaris motor and was racing my buddy who was riding my SJ. We were basically drag racing on flat water. The octane was running hard, but I could not pull away from my SJ with a simple limited setup. I feel the octane will be a much more fun boat with a 780cc 61x/62T setup. Lighter, more punch, more reliability, cheaper parts etc....

 

[ryan]

the weight and the huge flywheel. price of parts . that who knows how long you can get them. have a motor issue no back up. i got yamaha motors all over the place. my motor plates were coming out anyway. keep pancaking that thing upside down that motor will be out in no time.

 

[cjbchopper]

Got some work done tonight. Peeled out the old mounts. They came out pretty easily, there was not a very good bond to the aluminum. Should be getting a UMI coupler in a couple days so I can line up the drive train. I have two different props for the Solas pump, a 14/21 concord and the stock 15/23 concord. Anyone have any prop experience with this engine setup and a solas pump?

 

[speedysprocket]

What are you doing with the Polaris engine and the electronics...?

 

[cjbchopper]

Yes, I will be sellling the Polaris motor and electronics. It seems that these skis generally always leak in the foam. I have had drain plugs installed for the last couple years. I plan on re-foaming this weekend, was thinking of doing the ping pong ball idea and foaming over the top of them. Maybe this way at least the water couple drain out he back rather than sitting in the foam.

 

[speedysprocket]

I filled the lower half of the tray with ping pong balls. I think it was the box of 400 and something from ebay. The foam gets all in between the balls, so it doesn't drain like you'd hope for, but at least the balls provided buoyancy that will never waterlog like the foam.

 

[DiagNuLL]

That Yamaha looks great in there, i'm really interested to see how it turns out and what you have to do to get the engine positioned.

When i did the foam on mine i crammed it full of 2 inch green foam from Lowes. I wedged these blocks in, but i also cut channels in the foam along the bottom and a few vertical channels between each block so that any water that gets in there can move around and hopefully find its way to the drain plug easier.

 

[Joker]

Idk if this would be a big problem but if you put ping pong balls next to a thru hull exhaust tube, wouldn't the balls expand and possibly rupture since they are full of gas?


Ice and aspirin heals any wound 

 

[madness maker]

just about everywhere.ride plate bolts, pump bolts ,bulkhead,cooling tubes. where you ride out of?

out of wantagh park, and ride west end/jones inlet.

 

[ryan]

i ride same spot never seen another octane ever. you need to come on down to lido beach ramp and ride with us next year. out of lido saves you all that ride time to get to the ocean.

 

[NVGuy]

Mine is getting there slowly, but now i can say im just waiting on parts.