650/X-2 X2 money pit

[eddie747]

Im currently building my x2. It started out with a hot 650 that lasted 2 seasons, did a full rebuild and had the crank break after 3 hours and wreck everything. I switched to a super clean 750 big pin and have plans to wake it up on the bottom a little. I know it will never be as snappy as the 650 but this motor was cheap. I built a custom tank mount for a 2 gallon tank, shaved hood, a ton a hull repairs, and a bit more small custom stuff. Just looking for some input if its worth waking this up or putting it in my other x2 for a race ski and building a 701/760 for a freeride/play ride ski

 

[Vumad]

I dont think the 750 is more or less powerful than the 650 on the bottom, but certainky so on the mid and top. This is depended on the pipe. My 750bp with44s and b-pipe is massivelymore powerful than my buddys 750sp with 650 am pipe and a single 44, but only in the mid and top really.

None of the kawis ive riddenhit likemy superjet including sxr 800 with b-pipe. It could be factors of weight and wetted surface but i think the yamaha hits sooner and winds out earlier. Ive never ridden a 701 kawi so i cant comment on that, bjt the superjet motor and b-pipe fit better in the x2 than the kawi does with the bpipe.

 

[eddie747]

Thanks! All very good information. I figured with the time and money spent to get the 750 to hit harder it would make more sense to find a 701 and b-pipe. I feel like my stock superjet revs faster and pulls harder off bottom than the 750 with 180 psi compression too but you can really feel the 750 come on mid to top

 

[Vumad]

Thanks! All very good information. I figured with the time and money spent to get the 750 to hit harder it would make more sense to find a 701 and b-pipe. I feel like my stock superjet revs faster and pulls harder off bottom than the 750 with 180 psi compression too but you can really feel the 750 come on mid to top

The kawi will make the power, but prop it to hit hard sooner means it can wind too high. Depends on your goal. If you want a multipurpose x2 the yamaha is a good compromise. The surf riders do the same thing to the yamahas, that is prop them to blow up if you race them. You can always start with a kawi and prop it real low (I don't know what prop you would need). Let the kawi into the midrange sooner and it'll pull hard.

Again, I haven't but ridden a 701 x2. I have rode a 10second kawi it it was okay. I want to be able to run bouys too though so a 10 second ski isn't for me

 

[eddie747]

I did some more research and it sounds like a dynafly 12/21 works real well with the 750 for the bottom end hit. I'll keep researching and call Impros and see what they think also

 

[Vumad]

I did some more research and it sounds like a dynafly 12/21 works real well with the 750 for the bottom end hit. I'll keep researching and call Impros and see what they think also

Improve told me I needed a hooker 10/16 and they were wrong. I should have sent it back but I didn't. Probably have to pay to have it repitched.

The guys with 750s I have spoke to say they run 9/15. I think hats general purpose not 10 second for bottom end.

I have a 750 bp FPP superjet pipe, my own waterbox, dual 44s, 180 psi and lightened flywheel. Hooker 10/16 is too much for rec riding.

Remember different brands are pitched different and big hub is different than small hub so the hooker pitch doesn't mean the dyna fly pitch is wrong.

Careful what you read online, my posts included. Lots of people have poorly tuned x2 and say they are great. Mine runs like poop but at least I acknowledge it (think it's all prop but I'm too lazy or cheap to fix it). Also most x2 are Frankenstein so even if they are tuned right it's rarely apples to apples.

 

[x2mafia]

9/15 is perfect. Ski hits on the bottom and rips on the top

 

[eddie747]

Improve told me I needed a hooker 10/16 and they were wrong. I should have sent it back but I didn't. Probably have to pay to have it repitched.

The guys with 750s I have spoke to say they run 9/15. I think hats general purpose not 10 second for bottom end.

I have a 750 bp FPP superjet pipe, my own waterbox, dual 44s, 180 psi and lightened flywheel. Hooker 10/16 is too much for rec riding.

Remember different brands are pitched different and big hub is different than small hub so the hooker pitch doesn't mean the dyna fly pitch is wrong.

Careful what you read online, my posts included. Lots of people have poorly tuned x2 and say they are great. Mine runs like poop but at least I acknowledge it (think it's all prop but I'm too lazy or cheap to fix it). Also most x2 are Frankenstein so even if they are tuned right it's rarely apples to apples.

All good info thanks! There's a lot to learn with this being my first real big build. I heard running ECWI on the factory pipe also helps with the bottom end on the 750's. Im running a 3 piece mariner for a 650 now and thinking about build a few different length convergent cones to see if that will help also. Not sure if anybody has done this before but it's worth a shot.

 

[eddie747]

9/15 is perfect. Ski hits on the bottom and rips on the top


Im assuming thats a hooker 9/15?

 

[Vumad]

Yes,
Hooker

 

[Vumad]

All good info thanks! There's a lot to learn with this being my first real big build. I heard running ECWI on the factory pipe also helps with the bottom end on the 750's. Im running a 3 piece mariner for a 650 now and thinking about build a few different length convergent cones to see if that will help also. Not sure if anybody has done this before but it's worth a shot.

There is a 650sd build thread where a guy made his own pipe parts.

If I was back at the beginning, I would either leave it simple with a 650/750 with a am 650 pipe or do a 701 conversion. The Rhaas kits weren't available back then but the b-piped 701s in the x2 look great just google 701 x2.

 

[eddie747]

Looks like the 701 and b-pipe fit in there perfectly. I'll see if i can get this setup to work with an impeller and maybe start looking for a clean 701 to do a swap

 

[Vumad]

Looks like the 701 and b-pipe fit in there perfectly. I'll see if i can get this setup to work with an impeller and maybe start looking for a clean 701 to do a swap

Be sure to have it done by next daytona so i can try it. I think i would love the 701 x2 but didnt want to take the leap. I may put my superjet motor in mine when i redo my superjet hull.

 

[eddie747]

For sure! Im dying to get to daytona, that would give me an excuse to do the 701 and get down there haha