760 superjet top speed build

Joined
Dec 17, 2014
Likes
1
Location
North of Brighton MI
#1
I searched and could not find a thread for a top speed superjet build. If there is a link please share. Possibly we need forums based on motors since motors go into many different things. I figure the 701 is like the SBC of stand ups.

The subject build is a 2012 Superjet, B-pipe, TDR water box, ADA head pump gas, perfectly tuned runs perfect pulls 6910 to 6950 rpm and 51mph on GPS., but most of the guys I ride with are running SXR1500's so going 50mph is not cutting it and buying a 500 pound ski doesn't sound like fun.

I have a Rickter with a PHP and PF pipe so if I need bottom end I have enough. For the super jet I'd like to get to 56-58 mph with no regard for low end punch. I have a complete 760 from a wave venture with a a fresh 1mm bore and pistons ready to build.

Need advice on porting, if any needed and impller pitch, ride plate recommendations, etc. I want to do this with the current B-pipe and pump gas, other than that I'm open.
 

powerhouseperformance

www.PHPSKI.com
Site Supporter
Joined
Nov 2, 2011
Likes
311
Location
wisconsin
#4
56-58 is a lot more doable with a dry pipe but my stock class superjet race boat with an r&d wetpipe does 52.5 as is. With porting, compression, ignition, carbs your goal is pretty easy
 

Big Kahuna

Administrator
Joined
Jan 14, 2006
Likes
7,771
Location
Tuscaloosa, AL
#6
Give you 2 pieces of advice. Contact Zack and Powerhouse Performance and let him guide you through your build, let him port your cylinders. For Speed Info, you may have better luck on PWCToday, find threads that are older, like 2003 or so. There are not many racers or speed freaks on here.

That said, The BPIpe is going to limit you. I would look for a Type 4 High Rev, Type 9 or Speedwerx pipe. The Type 8 was the biggest flop Factory Pipe ever made in my opinion. Tricky on here use to have a SJ with a Type 9, DASA 6mm Stroker (Old Cast race cylinder) that GPS's around 61-62. It was scary fast.
 
Joined
Feb 26, 2017
Likes
318
Location
Minnesota
#8
This is interesting to me because it is a change of pace from all of the "I want that freestyle low end hit".

So I'll try out Cunningham's law. Warning: I don't know what I'm talking about and you should listen to somebody else who does.

64x cylinder 1mm over

Lots of port timing because you are not very concerned about low end, maybe 192/125 exhaust/transfer. Flatten top of transfers to a couple degrees from piston crown, point more toward exhaust port compared to stock yamaha. Big round corners on exhaust port.

The usual case porting.

Don't go crazy on the compression because you'll be holding this thing pinned for long periods of time. Maybe 40mm domes in an ADA girdled head

Zeeltronic

Low buck: use the stock 64x reeds/intake/carbs

High buck: your favorite flavor of 48mm carbs (Novi), your favorite flavor of big intake (PHP), VF3's

Run the B pipe as dry and hot as you can get away with.

I wonder if the bore on the header should be opened up to 50mm??


Low buck pump: solas

High buck pump: setback skat 140mm

impeller...no idea. Probably higher pitch than what everybody is using for freestyle.


Hull mods for high speed: I have absolutely no idea. (Prowatercraft pump tunnel stuffer?) Maybe straight back nozzle? (oem 08+ superjet is angled up slightly)

Also I think @waxhead is into this sort of thing, so maybe he can chime in if he is so inclined.
 

waxhead

wannabe backflipper
Joined
Jan 15, 2006
Likes
942
Location
gold coast
#11
This is interesting to me because it is a change of pace from all of the "I want that freestyle low end hit".

So I'll try out Cunningham's law. Warning: I don't know what I'm talking about and you should listen to somebody else who does.

64x cylinder 1mm over

Lots of port timing because you are not very concerned about low end, maybe 192/125 exhaust/transfer. Flatten top of transfers to a couple degrees from piston crown, point more toward exhaust port compared to stock yamaha. Big round corners on exhaust port.

The usual case porting.

Don't go crazy on the compression because you'll be holding this thing pinned for long periods of time. Maybe 40mm domes in an ADA girdled head

Zeeltronic

Low buck: use the stock 64x reeds/intake/carbs

High buck: your favorite flavor of 48mm carbs (Novi), your favorite flavor of big intake (PHP), VF3's

Run the B pipe as dry and hot as you can get away with.

I wonder if the bore on the header should be opened up to 50mm??


Low buck pump: solas

High buck pump: setback skat 140mm

impeller...no idea. Probably higher pitch than what everybody is using for freestyle.


Hull mods for high speed: I have absolutely no idea. (Prowatercraft pump tunnel stuffer?) Maybe straight back nozzle? (oem 08+ superjet is angled up slightly)

Also I think @waxhead is into this sort of thing, so maybe he can chime in if he is so inclined.
Pretty much agree with most of that, the oem 08 nozzle should give you more top speed but it will handle like crap.
Tighten squish. make sure your boost port is angled right, ie at the closest edge of the combustion chamber.
I did an indepth on porting a while back if you want to see it. I have a more aggressive curve for the zeeltronic that I run in my skis Im happy to share if you want it
http://greenhulk.net/forums/showthread.php?t=212410
 
Joined
Feb 19, 2013
Likes
5,243
Location
Chico California
#12
Pretty much agree with most of that, the oem 08 nozzle should give you more top speed but it will handle like crap.
Tighten squish. make sure your boost port is angled right, ie at the closest edge of the combustion chamber.
I did an indepth on porting a while back if you want to see it. I have a more aggressive curve for the zeeltronic that I run in my skis Im happy to share if you want it
http://greenhulk.net/forums/showthread.php?t=212410
Yes please! :D
 
Joined
Dec 17, 2014
Likes
1
Location
North of Brighton MI
#14
That porting write up on green hulk is excellent! I'm only through a few pages but exactly what I was hoping to find. looks like i'll be breaking out the Dotco and working on this cylinder myself. I've port matched a couple 701's because there's no point in running them stock after looking at them. I'm getting a lot of motors assembled during this work from home time.
 
Joined
Feb 26, 2017
Likes
318
Location
Minnesota
#16
That porting write up on green hulk is excellent! I'm only through a few pages but exactly what I was hoping to find. looks like i'll be breaking out the Dotco and working on this cylinder myself. I've port matched a couple 701's because there's no point in running them stock after looking at them. I'm getting a lot of motors assembled during this work from home time.
Post up about it if you have a go at it yourself, I'd be interested in seeing.
 

waxhead

wannabe backflipper
Joined
Jan 15, 2006
Likes
942
Location
gold coast
#18
That porting write up on green hulk is excellent! I'm only through a few pages but exactly what I was hoping to find. looks like i'll be breaking out the Dotco and working on this cylinder myself. I've port matched a couple 701's because there's no point in running them stock after looking at them. I'm getting a lot of motors assembled during this work from home time.
Thanks mate,, the engine went hard
Its going into an hx now
 
Top Bottom