Super Jet SJ 650 vs 760

9

90SJ

Location
Oxford, MI
I have a 90 sj 650 stock motor with aftermarket water box, prop, intake grate, and ride plate. It runs great but I am wanting more bottom to mid power. I can get a good running 760 for free. Would this give me more bottom to mid? I read 701 is the way to go, but the 760 is free. Thanks
 
9

90SJ

Location
Oxford, MI
Ok so I started the swap. I have a chance to get a R&D dry pipe. Would this be a good pipe for my set up? Also what would be a good prop?
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
90SJ said:
Ok so I started the swap. I have a chance to get a R&D dry pipe. Would this be a good pipe for my set up? Also what would be a good prop?
Click to expand...

It's decent, but it lacks bottom end. Combined with the weak bottom end of the 760 cylinder, it may not be the most ideal combination.
You could make it work with a higher compression head, a low pitched impeller, a better ignition, and possibly water injection.
 
J

jettmatt954

Location
S. Florida (954)
I have a 760 motor in my 03 rn set up for freestyle....after some porting work and a nice impros 10/16 impeller my ski runs great....currently running pro-tec dry pipe with water injection, milled head stock carbs (jetted) and all the rest of the normal bolt ons.....only problem with the 760's is they do not sell the msd spark box.....in order to run the msd you have to put in a 701 stator plate and flywheel (this is what i did and put a jetnetics lightweight flywheel on).....now motor has plenty of bottom-end brap for a freestlye/freeride ski
 
9

90SJ

Location
Oxford, MI
Thanks for the replys. I am using the 650 ignition. I looked for vforce reeds but couldn't find them for 64x cases, do they make them? As for the pipe it does come with a water injection controler. Right now I only have the stock 650 pipe. Would a factory b limited pipe be a significant differnce in low-mid power? The R&D pipe is $300 but the factory pipe is about $700. Worth it? Thanks
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
You'll be happier with the B-Pipe in the long run.
You should get a 701 CDI because the 650 CDI has a very low rev limit. This will hold the motor back, especially if you get the R&D pipe.
As for reeds, anything that fits the 96 and up Superjet (62T cases) will also fit the 64X cases.
 
9

90SJ

Location
Oxford, MI
I got the motor in and running. I am using the 650 exhaust until I can find a used b pipe. The 760 is out of a 96 waveraider, the carb is stock. I did clean it tho. Can anyone give me some baseline jet suggestions? I did notice that the jets were not the same sizes in each carb. Not sure why. Thanks
 
Al//gsx//sj

Al//gsx//sj

Location
Lafayette,La.
OEM parts finder showes Carb 1 @ 135 and Carb 2 @ 137.5. pilot looks to be 115 for both. i'm guessing issues with the 2nd cyclinder starving for fuel? humm...not in a Yamaha? lol
 
9

90SJ

Location
Oxford, MI
Yes that is what sizes they are. Anyone have any jetting suggestions? Plugs are very wet, and it's not really even rideable. Just bogs out unless giving gas very slowly. Thanks
 
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