650/X-2 Surf x2

[naithgroves]

Hey Guys,
I just picked up this little beauty on the weekend and it ended up costing $200 on the trailer! The ski is stripped of motor and pump and has been painted. It came with a 650 all disassembled but machined ready to put together with new pistons, seals, crank, 40 something mm mikuni carb, west coast manifold and flame arrestor and an after market power pipe. The hull looks to be in pretty good shape but has had a repair right under the motor and will need re-doing. The pump is stock and looks like it needs attention as the prop binds 3/4 rotation. I Have done a search on what prop i should run with the engine setup and it looks like a 9/17 scat is the go?

How do you think the 650 will be for power? With the engine mods I have is there anything else that will help it work better?

Looking forward to getting it started!!

 

[Nuklear6]

Already went through the natural progression your about to start. All I can say is do yourself a favor and find a 750 to drop in her now! It will be the end result anyway. And as far as the prop and pump go, I would looks closely at the liner around the prop in the pump. They are known for swelling and not alowing the prop to turn all the way around.

 

[shawn_NJ]

^^^^What he said^^^^

But if your strapped for cash just run the 650. Also, that carb is a BN....Do yourself a BIG favor and ebay it, then get a SBN.

 

[AirBruceX2]

THose bars are definetly holdin ya back....Get some fly bars they are like 20 bucks

 

[tomthewakeboarder]

The paint looks solid, I'm a big fan of the straight white. I agree with the 750 comment, but as I don't have enough money to go that route I just run the 650 and since I haven't ridden anything else I can't tell the difference... so if you're worried about power just stay away from wicked machines and you'll never feel like yours is no good.

 

[naithgroves]

Thanks for the help guys. What should i do with the pump? Does it need to go to a machine shop or are there methods I can use to do this at home. Have lathe bench grinders etc. So how down on power are the 650s to 750s? Would a 650 be a bit underpowered in the surf? Im doing it to a budget and figure the parts are all there so might fit it all up and on sell the 650 once I get used to it.

Is there anything else i can safely do to the 650 to help on power like milling the head for a tad more comp? Or machining the fly wheel to be a bit lighter?
I would love to throw a 750 in it with the 650 stator and fly wheel. One day.

 

[tomthewakeboarder]

I'm not sure what to do with the pump. Maybe finding another used one would be easier than fixing it? I'm not sure if a 650 is going to be underpowered in the surf, but I'll let you know on Monday once I ride 'er for the first time.
Again I haven't done any engine work but I know you can bore the cylinder and move up the cc's. You can also buy Ocean Pro high comp heads that are easy to install but when I had mine on I blew gaskets like crazy and you need to run race gas. Machining the flywheel is a good idea but you need someone that knows what they're doing to do it. Apparently its easy to put it out of round even on a machinists lathe.

Check out my build called The Begining... some guys have posted a lot of good info in there.

 

[Winter X2]

Sell that 650 for $400 and buy a 750. Its night and day and you can use all of your same electronics with a little mod where the stator plate mounts.. Anybody who says that they are comp motors, hasn't rode an x2 with a 750. I could buy a factory fresh x2 with a 650 in it and I would swap it right away. just my 2 cents. 46mm sbn is what your looking for if you sell the other carb.

 

[Wilke]

You can mill down the head to bump the comression, but this is something you would need to send to a machinist, cause it has to stay perfectly flat to seal against the cylinders. I'm not sure how much you need to take off, but you don't want to go over about 175-180psi if you still want to run pump gas (91 or 93 octane)

With the pump, if the liner is swelled you can grind it down a little to clear the impeller depending on how bad it is. I ran a pump I did that to for a while with no issues, I did it with a dremel. But since you need a prop anyway, look around, alot of times you can find a nice used pump with an aftermarket prop already in it.

A 750/800 isn't a nessecity, just an extra bonus. The 650 with an SBN/pipe/prop will do you just fine in the surf. Just don't go riding anyone elses big power skis if you don't want your wallet to suffer the consequences.

 

[Nuklear6]

i may have a west coast head for a 650 that would make around 170psi on the compression gauge. you can have it for whatever the shipping cost me. PM me if your interested and ill try and dig it out.

 

[naithgroves]

Thanks alot guys. Stoked with the response for help in here! So the pump seems to be ok as I forced a full turn out of it with the drive shaft on it. Might just fix it self once started up and running.
I'm going to have a crack at porting the intake manifold this week for some more o2. Not sure about how much I should be taking off the fly wheel but i figure common sense will prevail. I scored a set of renthal bars and a umi finger throttle from a mate over here who is building an sxi standup.

Will be having a close look at the steering clamp and will probably do the bolt mod and shim it all up to make it nice and tight. Also going to make some flexible hose run from the intake to the hull floor so water does not spit around in the hull when out in the surf being dumped. Saw something similar done on Pete Jacob's x2. Going to wire wheel the engine cradle and repaint as well as get some vinyl and recover the seat.

Scratching my head about chopping 1.5 inches off the back of the ski but have some glass work to do before it hits the water and since I have never ridden an x2 i might not? Dunno.

Thanks again for the help Fella's,

 

[naithgroves]

 

[tomthewakeboarder]

Be careful with the flywheel man. I haven never done it but I have heard mixed responses from people. I think its recommmended to take about 1/2 a pound off the outside I believe.

As for the hull chop, it was the easiest mod to do. I used a reciprocating saw with a dull blade and it took me literally 10 minutes. I shoul dhave taken a bit more time because the saw went off course a couple times and cut some nice gouges. I also thought about trying to save the stern eye so i could use it to tow people. But that was in hindsight. You don't even need to do any glass work if you do this mod. Its all sealed nice and as long as you don't take too much off (more than 1.5") then you're good to go. Can't say until I ride it to notice any performance but it makes sense. Just try and turn your nozzle and see where the water is going to hit the sides.

 

[tomthewakeboarder]

Nice floats for it by the way. Excellent for beginers and girls.

 

[naithgroves]

Great I'l definitely chop the back off when glassing the hull then! Thanks.

Yea I didn't know it came with the floats. Bit of a bonus. My Missus is going to love next summer because her and all her friends can come ride my ski. :scratchchin:

I might get the fly wheel machined and balanced by the shop that does my drive shafts but will do a little more research.

How about the rev limiter? Is there one or a mod to lift it slightly?

 

[shawn_NJ]

How about the rev limiter? Is there one or a mod to lift it slightly?

The rev limiter is internal to the 650 CDI. It is not adjustable. Porting the intake manifold will mess with the carb signal, you may/may not want to do that. Also I highly advise against running that carb. Its a nightmare to dial in.

 

[naithgroves]

Oh yea i forgot to mention I picked up a 44mm SBN on your advice the other day for $90. If i port the manifold then jet the carb it should be alright ? Found a guy here that is really good with parts and got the fly wheel cover, screws, stator screw, oil pump block off and an engine mount that was missing from the ski for $60.

All coming together, just need to grease the elbows

 

[shawn_NJ]

Good call on the 44. I never tinkered with 650 intake manifold so cant help you there.

 

[naithgroves]

 

[naithgroves]

And a couple more.....

Turns out the Finnish mail order brides have skillz!

Found a nasty repair and hacked out the no good. Now for a first time at it fiber glass repair.