- Location
- Annapolis, Maryland
It wasn't from either of them. It looks like mine was modified from one of the oem Yamaha shafts that has the hardened tip on it like you mentioned earlier.
2 Season Old Driveshaft Failure
- Thread starter JKMike
- Start date
It wasn't from either of them. It looks like mine was modified from one of the oem Yamaha shafts that has the hardened tip on it like you mentioned earlier.
- Location
- North Carolina
Sbt makes a shaft that has the same “hardened” tip. I can tell the difference by the heat treat coloration at the bearing end.
- Location
- the jetski grave yard
Oem Yamaha shafts are put together from 3 pieces. The splines are less stainless and more steel, so it's going to rust more. I've got a stack of shafts laying out in the boneyard and some are pretty crusty on that end. Thats why Aftermarket garbage shafts strip out in 2 seconds. They aren't hardened where needed. I had a garbage shaft in a pos wdk rokr. It used the gp midshaft where the splines are basically in te coupler. The garbage shaft wore just enough to lock together with the Mid. What a pain to get it apart
long beach local
long beach local
- Location
- Az
I agree with this. My carbon sf has many hours on it in salt water and i have very little corrosion . It was built with an oem midshshft new seals ,aligned and greased siliconed in etc and I had no issues.
- Location
- North Carolina
The OEM shafts I recondition are in my opinion the best bang for the buck at $165. Then new Oem if it has to be new.
- Location
- United Kingdom
What is the maximum runout you can have on a shaft?
- Location
- Ahwahnee, CA
Early 90-93 manual says .5 mm
Later 96+ manual says .3 mm
Later 96+ manual says .3 mm
The engine shakes a lot so there will always be some movement between the two shafts. Any binding seems to make it wear more. The real problem has a simple solution that very few riders are willing to address. The midshaft must be removed, cleaned, and lubed every time the pump is removed. The hull also needs to be cleaned before reassembly. I have never known a rider that would do all this work but Ive known plenty who have lost their splines.
- Location
- the jetski grave yard
I don't actually see failure. All I see is rust. Splines don't look stripped out to me.
As an experiment on my last am hull I installed my pump, aligned it with a Cold Fusion tool , installed mid shaft. I pulled pump , reinstalled with same shims and then pulled mid shaft. When I rechecked alignment with CF tool it was way out. If you pull your pump, your alignment is gone.
- Location
- Annapolis, Maryland
Interestingly the splines inside the midshaft look fine to me. There is some wear at the end of the midshaft near the o-ring groves but other than that the midshaft looks OK. Now while there might not be much wear on my splines the portion of the shaft where the O-rings ride is too rusted to ever be saved.
- Location
- Annapolis, Maryland
Has anyone thought about adding a grease fitting on either the midshaft itself or on the outside of the midshaft side coupler to re-grease the splines without a full disassembly?
- Location
- Annapolis, Maryland
I could see this with the pump especially if you have any slop in the pump mounting holes. Mine are so tight the pump can only really sit in one spot.
Question for ya though, do you either use the alignment pins with your CF tool and midshaft or, if you don't have pin holes, install the CF tool with countersunk bolts and initially install the midshaft with the same countersunk bolts, tighten them all down and then remove and swap the countersunk bolts for the standard ones, one at a time. Personally I have found this to give me a more consistent installation location with the midshaft.
- Location
- Michigan
I thought about trying this, just tapping a hole on the midshaft side between the coupler and spline area seems like it would work… however my concern was if it would weaken the midshaft too much and be a fault point for it to crack / snap.
Actually the key to it working properly is to drill 2 holes. One for a zerk fitting and a second for a relief port. I did this on my FX's w/ OE mid shaft housings. Just make sure internal hole you drill lines up with the grease passage in between seals. By having a relief I could completely flush old grease with new. Another advantage of drilling grease ports in the midshaft, if I did pull pump, by removing plug at coupler you could relieve hydraulic lock when pushing pump shaft back in, pretty much the reason the 2 internal o-rings are always blown out.
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With am hulls and no register fit of any kind for either the pump or the mid-housing I don't bother. I align pump shaft with CF tool to bulkhead, then I bolt mid-housing onto bulkhead just making sure it is parallel, or flat on bulkhead. All the float in the bolt holes let's it marry up where it needs to be. I do this without the coupler half on the mid shaft to prevent blowing out the 2 o-rings, letting excess grease come out of the front of the shaft. The Yami design (splines close to motor, lots of movement) in my opinion loses points to the Kawi design (splines far from motor, less movement). The down fall of the Kawi is your splines in flow path, but as long as your prop seal is good not really an issue. Pros and cons to everything. One thing I thought was a step in the right direction was the way the FX1 pump was mounted with the ball and socket gimbals in the front pump feet, sort of an effort to register the pump fit. The rest of the pump (122mm) sucked, and the aluminum gimbals corroded out but I fixed that with stainless gimbals.
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