Super Jet trouble with stripping driveshaft splines on lenzi hull

[scootinhooten]

The ski is a 03 carbon fiber Freestyle sj hull made by lenzi

Running heavy duty sj driveshaft with OEM midshaft

Been through 2 mid and driveshafts in 3 hrs ride time.
has anyone had similar problems? Or have advice, maybe something wrong with the current set up?

 

[Christian_83]

Maybe you could give more details about your setup.
Are you pump, midshaft and engine shimmed and aligned 100%?
Do you have any pics of your hull ? Im a little courios?

 

[slinden]

Id guess you have a serious alignment problem.

 

[Daralekt]

Id guess you have a serious alignment problem.

yeah. what he said.

 

[Schmidty721]

Are you getting sufficient spline engagement between the drive shaft and mid shaft?

 

[Crab]

Lack of engagment, AM hulls vary alot.

 

[JetManiac]

Id guess you have a serious alignment problem.

Are you getting sufficient spline engagement between the drive shaft and mid shaft?

Lack of engagment, AM hulls vary alot.

x2 on these comments.

Post up a pic of your stripped driveshaft splines.

Do you have crazy vibration while riding?

 

[scootinhooten]

Thanks for the replies,.... I will get pictures taken tomorrow when I get back home,
no bad vibration in it that I have noticed
first shaft I stripped is 3/4 inch shorter than stock......it only stripped the first inch of splines. So I went to install a stock length driveshaft.... went to install the pump on the ski and it stopped 3/4 inch from fitting ... I had the splines milled farther onto the shaft by 1 inch .. I did not shorten the shaft any.... put it together and everything went together smoothly....that shaft went within a few hours ride time

Pictures will tell a thousand words tho ill have some tomorrow night

 

[Matt_E]

And what did you do for aligning a) the pump and b) the motor to the midshaft?

 

[scootinhooten]

As far as alignment motor to midshaft 100%
Midshaft to pump... I'm New to working on this part so it very well could be out of alignment . When I put it in nothing bound up but I'm not sure how to check for 100%

 

[scootinhooten]

As far as alignment motor to midshaft 100%
Midshaft to pump... I'm New to working on this part so it very well could be out of alignment . When I put it in nothing bound up but I'm not sure how to check for 100%

 

[CARBONX2]

Install pump/driveshaft first, spacer it until driveshaft sits cenratlised(Midshaft/housing slide straight into locating holes for pins)

 

[motoman96]

Most aftermarket hulls don't utilize the locating pins for the midshaft. Def sounds like an alignment or not enough meat grabbing the splines.

 

[Christian_83]

My carbon lenzi hull has locating pins, both for pump and midshaft.
I would def start by mounting to midshaft, and se through the pump tunnel to make sure if the midshaft centers or where the hole for midshaft sits. On my Gary watson i could see it sit a little low in the right corner. so i had to compensate for this by pulling the midshaft, and aligning the pump/driveshaft for this "center spot of midshaft" (down low in right corner) if i didnt see where the midshaft were sitting, and just aimed for getting the pump/driveshaft to sit in the middle, i would have caused stress on the driveshaft.
Throw some pics up, allso of the hull it self. Is it setback engine?
Im running a GP800/WR 1100 midshaft (120mm midshaft) as mine has setback engine

 

[Superjetjim]

I would def start by mounting to midshaft, and se through the pump tunnel to make sure if the midshaft centers or where the hole for midshaft sits.

What Chris said..

Also - if you have stripped your drive shaft your intermediite will be toast as well - you need to replace both at the same time or one will just eat the other due to poor engagement.

 

[JetManiac]

Thanks for the replies,.... I will get pictures taken tomorrow when I get back home,
no bad vibration in it that I have noticed
first shaft I stripped is 3/4 inch shorter than stock......it only stripped the first inch of splines. So I went to install a stock length driveshaft.... went to install the pump on the ski and it stopped 3/4 inch from fitting ... I had the splines milled farther onto the shaft by 1 inch .. I did not shorten the shaft any.... put it together and everything went together smoothly....that shaft went within a few hours ride time

Pictures will tell a thousand words tho ill have some tomorrow night

This may also be a problem. Oem splines are precision cut and heat treated. If the splines that you had cut are not perfect then they will create their own wear problems. I would stay away from trying to cut custom splines.

 

[scootinhooten]

tach]

 

[scootinhooten]

Not sure if its set back motor this is my first superjet

 

[motoman96]

Motor can't be setback, pump can be. Just look through the intake grate and see where the impeller sits compared to the wear ring.

 

[JetManiac]

View attachment 187239

Holy underlap batman!

You need to pull midshaft also and try to figure out why your driveshaft /midshaft combo are underlapped by approx an inch.