6m6 in js550

[1970Camaro]

I pulled the 650 6m6 from my 92 superjet and am going to put it in my js550. I got the kit from rhaas. What prop do you guys recommend? Stock pipe, stock 650 yamaha engine. I see 19 or 20 straight pitch is common, does it have good bottom end with that? Any body out there run a 650 with a variable pitch impeller?

Thanks!

 

[mikidymac]

I am working on the exact same build...

With the 650 you should run the straight 19. If you had the 701 and a pipe maybe 20.

 

[1970Camaro]

I am working on the exact same build...

With the 650 you should run the straight 19. If you had the 701 and a pipe maybe 20.

I appreciate the input. What year js550 are you building? Do you think the 19 will have enough pop off idle? Did you get an impros? I'm not as concerned about top speed as I enjoy the torque from idle.

 

[mikidymac]

Actually using a 91’ 440.

19 will be good, 20 will be too tall for a stock 650.

 

[1970Camaro]

Oh nice, 91 has rear exhaust. I have a clean 85, Im almost hesitant to swap it actually. Unfortunately I will have the noise coming out a big ole hose on the left haha

 

[mikidymac]

Looks nice.

Mine the engine was trash and I already had the 650 from a 701 superjet swap.

 

[1970Camaro]

I notice you are in California, what part? Where do you ride?

 

[mikidymac]

Central coast. Mainly Lopez lake and Nacimento. Keep meaning to do Pismo but haven’t yet.

 

[550headache]

If that’s a 1990 i think its a 440 with the decals replaced. I think 1991 was the first year of the purple lightning 550 with rear exhaust and reed motor.

Only reason i say this is because a old girlfriend used to race and i have her last ski and it was a 1990 SX. Looks identical to the 1991 except it ran a PP 440 and 440 driveline.


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[mikidymac]

If that’s a 1990 i think its a 440 with the decals replaced. I think 1991 was the first year of the purple lightning 550 with rear exhaust and reed motor.

Only reason i say this is because a old girlfriend used to race and i have her last ski and it was a 1990 SX. Looks identical to the 1991 except it ran a PP 440 and 440 driveline.


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Are you referring to me?
Mine is a stock 1991 440, nothing replaced or changed.
1990 SX is not the pink lightning, only 1991-1992 550SX were the pink lightning.
1990 SX looked like this and was the SX hull but with the old piston port 550.

 

[Rushford_Ripper]

I did one about 4-5 years back, had a straight pitch 17* jetlyne impeller in it, worked fine.

 

[_evan]

I’m slapping this 750 in this 440 hull and when we both finish we should ride! I live in SLO

 

[_evan]

If that’s a 1990 i think its a 440 with the decals replaced. I think 1991 was the first year of the purple lightning 550 with rear exhaust and reed motor.

Only reason i say this is because a old girlfriend used to race and i have her last ski and it was a 1990 SX. Looks identical to the 1991 except it ran a PP 440 and 440 driveline.


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You’re mixing up the 440 and 550. 91/92 440s had these graphics

 

[Sanoman]

Any updates on this build

 

[550headache]

You’re mixing up the 440 and 550. 91/92 440s had these graphics

Gotcha..i was misinformed..


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[1970Camaro]

Any updates on this build

I ordered a straight 19 skat trak from impros, just waiting on that to arrive before I tear into the ski. I expect it this week sometime. I'm thinking I will have to get new turf due to increased power. I'm also brainstorming ideas for a rear exhaust conversion, but I like my paint as is.

 

[E350]

Please post up how the install goes and how it works.

 

[1970Camaro]

I did one about 4-5 years back, had a straight pitch 17* jetlyne impeller in it, worked fine.

What pipe were you running in it? I have the OE 650 pipe, wasnt sure what other options there were, planning on running this pipe for awhile, maybe change it later.

 

[550headache]

You can always run a poor mans b pipe(stock kawi 650 pipe dried out and lengthened 3 inches),Coffman sizzler, or pjs 3 piece kawi 650 pipe. Or a FPP 650 b pipe if you can find one. Downfall is you will need a FPP exhaust manifold to run these pipes!
What will you run for a water box? I’m doing the same build but with a 701 and going to run a super trapp water box. A lot of people run sea doo(ugh) XP water box with great results. Guess they can be had cheap on eBay.


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[hawk2989]

I had great results with a poormans b pipe and seadonkey SP waterbox. The waterbox was heavy, and required you to convert to internal fill. It kept things respectable from a noise level though (and its cheap). I used a 19* straight pitch from Impros and it never had any cavitation issues. Glad to help out if I can.