Freestyle Driveshaft issues

[handshy13]

Has anyone ever seen a yamaha 144 driveshaft break like this

 

[OCD Solutions]

Yup. It happens all the time. Happened to me a couple years ago. The fun part is getting that broken stub out of the impeller and pump.

There's a couple threads with detailed instructions on how to get it out. I'll go look for it now...

 

[handshy13]

Ok thanks i guess thats to be expected since im running a dasa 998 10mil stroker and stock pump

 

[OCD Solutions]

That certainly would contribute but honestly, the shaft I replaced was in my wife's 07 Superjet and all she has is a ported 760 that she putters around on. Many believe it has more to do with mis alignment than torque.

Jetmaniac sells a beefed up driveshaft that will more than handle the power you are putting down and is less than $150 the last time I checked.

 

[handshy13]

Well i had kommander industries build it and put my my ski together that happened the first 30min of ride time and it was a new shaft.

 

[TheBuzzard]

i pulled the pump cone off and welded a big nut to it and got it off that way once. i think i used a pipe wrench on the cone end of the shaft another time

 

[handshy13]

Did you have it pressed out first

 

[TheBuzzard]

it doesnt work that way. you have to get the prop off to get the broken shaft out the rear of the pump. the shaft slips in from the back, then the prop screws on.

 

[handshy13]

Oh ok

 

[OCD Solutions]

Once I pulled the tail cone off, I discovered my shaft had a centering indent machined in the end. I drove a narrow flat chisel into it far enough to bind it up, locked the chisel in the vise and spun the impeller off. Since yours happened in the first 30 minutes, yours shouldn't be stuck on there too bad yet so hopefully it comes off nice and easy too.

I stared at mine for about 20 minutes, rummaged thru my toolbox and then had it apart in just a few more minutes.

 

[handshy13]

When i put it together with my 701 i aligned my pump and centered it in the midshaft hile i used 2shims on each side and aligned my motor correctly when i got it back no shims in the pump

 

[OCD Solutions]

I don't put much stock in the alignment theory myself. I believe you would strip out splines long before you would snap a driveshaft. My wife was jumping 4 fters the day she snapped hers on a landing so I believe it's a timing thing with inertia, impact and throttle all exposing a pre existing weakness in the driveshaft.

Was yours a new OEM, WSM or other? Does it taper down close to the impeller or is it the same diameter the entire length?

 

[handshy13]

No it broke at the thickest part it does taper im not sure what brand i had a shop order one but at tge time i had just a mild 701

 

[OCD Solutions]

Do you remember what you paid for it? That's probably the best indicator of what brand it is. New OEM should be around $250 where WSM are around $150. (WSM are junk!)

Not sure about SBT...

All I will run is a Jetmaniac shaft. I even had him make me up a spare for my Skat setback pump because the Skat shafts are notoriously soft as well.

 

[TheBuzzard]

thats also one of the 3 places shafts are assembled. i have a bunch of them that show a crack forming there.

 

[handshy13]

I paid 225.00 and its a good friends shop

 

[handshy13]

Ok im just so concerned about the alignment now

 

[OCD Solutions]

I'm leaning towards a weak driveshaft. It won't hurt to check alignment and that motor mounts are intact but i wouldn't lose sleep if you didn't find anything obvious. All the people I know that have done it, found nothing wrong, put a new shaft in it and kept on riding with no further issue.

 

[handshy13]

My motor to midshaft is perfectly aligned but how can i align my driveshaft with the motor in it

 

[amitchell]

You can't. Align the pump/driveshaft in the midshaft hole first, it should be dead center. Then midshaft to pump, then engine to midshaft.