Anyone have the same problem as me? Midshaft keeps getting pushed back in the housing

[Gliderskier]

Any else have this problem. It already happened once were the couplers came apart. I put a new midshaft in before daytona and after only four days of riding it moved back 16mm
Anyone have a solution for this. I know the cause is from hitting the nose in the bottom and the motor slamming back into if. My Kenny keepers are bent to no end as well

 

[DAG]

Replace Kenny keepers. Also what motor and motor mount combo?

 

[JT_Freeride]

He has a 701 with 6 motor mounts that's right 6 lol on a fr2.

 

[Crab]

I have seen the bearing go bad and allow this, changed it and all ok.

 

[BruceSki]

Did you find that other Kenny keeper?

 

[Draggingto]

The only time mine ever did that is when i broke 2 motor mounts.

 

[Crab]

I might add the short shaft had no wear

 

[Gliderskier]

I have 6 oem mounts. Four are brand new. And yes @BruceSki that Kenny keeper was in the back of the hull along with the two sheared motor mount mounting bolts

 

[Proformance1]

Whos mid shaft, new oem or other? I ask bacause we are having an issue with an aftermarket midshaft OD tolerance on a new build

 

[Gliderskier]

Good clean oem midshaft

 

[augustaf]

Don't have an a/m mid shaft to measure, have 2 oem's however. Checked my mikes against a Starrett 1" standard- right on the money. The 6205 bearing has 25mm bore. That would be 0.98425" here in the US- with a tolerance of 0 to - 2/10th (if better than a crappy ABEC 1). Proper shaft fit would be: same size. I measured 2 oem SJ drive shafts (they use same bearing size). One measured 0.9842" on both ends, the other shaft 0.9842" on one bearing location and 0.9843" on the other . Right on!
Both oem mid shafts- (brand new) seem to measure 0.9848". That would mean a one half of a thousands press fit- somewhat scary (might restrict the bearing balls) but has always worked so far.

 

[augustaf]

Good clean oem midshaft

Doing vertical landings would probably be to blame. If the engine moves back far enough..... you could even lock the mid shaft against the end of the drive shaft splines- hard to separate.

 

[Crab]

one year old superjet with all stock parts.

 

[augustaf]

If it's on youtube, it must be true, otherwise they would not be allowed to show it. Yeah, sure.

 

[Crab]

If it's on youtube, it must be true, otherwise they would not be allowed to show it. Yeah, sure.

I was holding the shaft....couldn't believe it either when we pulled it apart. On a side note, its been fine now for over 5 years by just rebuilding the midshaft with Jetmaniac parts.

 

[Proformance1]

That would mean a one half of a thousands press fit- somewhat scary (might restrict the bearing balls) but has always worked so far.

Interference is required so that the clearance in the bearings is taken up so that they wear properly. Too tight or too lose and they wear.

 

[Gliderskier]

Problem solved.

 

[BruceSki]

You can't be stopped with that tig welder!

Just start welding up a hull.