Super Jet How do diagnose which bearing is dying

[swapmeet]

I have a 144 pump with fairly fresh bearings but i'm positive that my alignment is off.
Getting a whirring sound from my pump area while riding. A local rider who's kind of my go to guy said its likely a bearing, could be one of the pump bearings, could be midshaft.

Is it real obvious which one is shot? Or do you just ride until they eat it? My plan is to replace the suspect bearings and align everything correctly.

I assume that there would be some play but wanted to ask ya'll.

 

[Waternut]

Pulling the pump and spinning it by hand would be the best solution. Then you could remove the spark plugs and spin the coupler to see which one is binding. If you really don't want to do that, I guess the midhshaft body would be pretty hot after a few minutes of riding if the bearings were going bad.

Alignment should be priority #1 though. IMO, "ride til failure" usually fails more than one thing.

 

[Tyler Zane]

like waternut said, pull the pump. i would not let it ride until catastrophic failure occurs.

 

[Matt_E]

Where's your guys' sense of adventure?

 

[Tyler Zane]

dang matt, we are trying to ruin sawpmeets fun.

 

[Freakrider]

It took quite some time to figure out that midshafts running high rpm get hot regardless if it has a new bearing in it. The midshaft will run hotter with a double lip midshaft seal in it like the blaster ones are designed. (I once cut the second lip off in the ski and it instantly ran cooler). Rubber seals riding on a high rpm midshaft create some heat. Follow Waternut's advice to diagnose...have you listen to it out of the water running on a hose ?

 

[swapmeet]

I'm not a "run it til' it breaks" kind of person LOL... just figured i'd throw that out there.

It took quite some time to figure out that midshafts running high rpm get hot regardless if it has a new bearing in it. The midshaft will run hotter with a double lip midshaft seal in it like the blaster ones are designed. (I once cut the second lip off in the ski and it instantly ran cooler). Rubber seals riding on a high rpm midshaft create some heat. Follow Waternut's advice to diagnose...have you listen to it out of the water running on a hose ?

I have not, I suspected that something has been amiss for awhile, but couldn't put my finger on it. I was riding Sunday and I heard a beautiful tune from a place that it shouldn't come from. It sounded just like supercharger whine.

I'll pull the pump and check it out. I was hoping there would be a sign of some nature on how to identify which bearing it is. Hopefully I can figure out if its the Pump or midshaft and just replace everything on the suspect part.

 

[kevbo]

The midshaft bearing gets wet and corrodes much more quickly than the pump. They are good for about three seasons. Make sure the pump brarings are quiet and there is notceable seal drag.

 

[OCD Solutions]

Bearings are cheap. I buy them in 10 packs. If I am going to take the time to pull components then I am going to change the bearings out regardless of what I find. You can replace the bearings in both the pump and midshaft in half the time you already have into troubleshooting alone. Spend the time you would have spent looking for the problem doing an engine/pump alignment so it doesn't happen again.

I do the same with airleaks. I can pull an engine, break it down, clean and completely reassemble it in less than half the time others usually spend just trying to find the leak.

 

[JetManiac]

That is the same pump you have had driveshaft in and out of several times?
You can easily mess up bearings while swapping driveshafts.

What is the age of the midshaft bearing? Kevbo is right on the money, I replace bad midshaft bearings often.

 

[swapmeet]

That is the same pump you have had driveshaft in and out of several times?
You can easily mess up bearings while swapping driveshafts.

What is the age of the midshaft bearing? Kevbo is right on the money, I replace bad midshaft bearings often.

Midshaft? I have no idea. Its the one that came with the ski when I bought it from Brett. I bought a spare from Motoman96 because I know they're hard to come by, especially when you strip the splines out. And given my 'custom' driveshaft I figured being prepared is the best plan. No idea how old the bearing are in the spare either.

I've had that pump and shaft out multiple times. The bearings are new, you helped brett put them in intially, but i've had them in and out probably 4 times since then for various reasons.

If you sell midshaft bearings and seals i'll probably just buy the whole lot from you. I'll ride on it this weekend and swap it all out next week before our camping trip on the 1st.

 

[JetManiac]

Be very careful when using a press not to damage new bearings by overpressing or by pushing from the wrong spot.

 

[swapmeet]

I may or may not have been using a hammer and a appropriately sized pipe to install my bearings.

:theyareontome:

*edit* Got my new bearings in today, thanks Chris!

So when you say 'don't push on the wrong spot', what is the correct spot?

 

[Sospikey]

I may or may not have been using a hammer and a appropriately sized pipe to install my bearings.

:theyareontome:

*edit* Got my new bearings in today, thanks Chris!

So when you say 'don't push on the wrong spot', what is the correct spot?

On the outer "ring" when installing the bearing in the housing. Try finding a large socket which has a diameter very close to the outer diameter of the bearing and use that to press/hammer the bearing in. Try to use a press, hammering the bearing in is always risky...