Should I replace jack shaft bearings with new track?

MN98VMAX

MN98VMAX

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Wondering if anyone has an opinion on this? I've got two '98 VMax's, one 500 (4,2xx miles) and a 700 (48xx miles). I've got two new Ripsaw's for them, but a friend said he heard if you're doing that you should do the jackshaft bearings too? Another friend said you might as well do the chain too! Yikes, this is starting to look expensive!

Any thoughts on these or other items I should look at while I'm in there?

Thanks!
Mike
 
I don't think you "need" to replace them just because you are going to slap on a new track. If the bearing are due to be replaced, then go ahead and replace them. I don't think there is a direct link between swapping out your track and swapping out the jackshaft bearings. Since you have the axle out, you may want to swap out driveshaft bearings, i'd recommend that since it involves yanking out the drive shaft. Not a "must do", but a "check things while it is out" type a deal. Regarding the chain and gear, I'd say that if they are getting work, and they may be getting there with almost 5000 miles, you can do that on the same premise as the jackshaft bearings. Opening up the chaincase is quick and easy, not sure i'd worry about it too much if you were not experiencing any problems. With the new ripsaw, maybe he was thinking that with the additional bite, you may wear your gears faster???? I suspect he was saying that from the perspective that since you have it apart, go ahead and swap out the other components. I'd just install the track and inspect things to see what needed TLC and go from there. Definitely inspect your speedo bearing there on the driveshaft, it is common moisture gets in there and it goes bad.
 
Here's my 2 cents. I have a 98 Vmax sx that I bought last year with 3600 miles on it. I put a new track on in February. My thoughts were, since I really don't know the maintenance history of this sled and since I have it all apart, I'll replace the bearings in the chaincase, the jack shaft bearing and the axle bearing on the speedo side. I bought all my bearings at Motion Industries in Roseville, MN they cost about 1/3 (or less) than what they would have cost through the dealer. Just take your bearings with you when you go there. They'll measure everything and make sure you get the right ones. They were very easy to work with. I did replace the chain and the top gear, the chain looked worn, and I wanted to gear one tooth down. Compared to what a new track costs, the bearings and chain are nothing. This all for me boils down to peace of mind. The last thing you want to do is to have bearing meltdown or chain failure out on a trail.
 
MN98VMAX - Peace of mind is good, that allows us to sleep easy at night. Sleddineinar makes a good point, if you do not know the service history and/or the quality of care that has been performed I too would swap them out since you have it apart already. At some point you'd inspect and replace bearings that need it either by failing or detecting wear even if you weren't swapping out the track out. In your case, you have an opportunity to do both for convenience. Obviously on a new sled you could swap tracks without replacing bearings, gears and chains as they would be new.
 
What really matters is the condition of the bearing, the amount of lube left in it, and the state of the seals. These are simply normal bearing considerations. You should check them all out closely and replace if they are not in real good condition. The jackshaft especially spins at a very high rpm. Those bearings go from marginal to shot in a single ride. I have seen them look ok (but not real good) before a ride, and burnt up enough to bend the jackshaft after that same ride.

If they are not in great condition, it is a great time to replace them when swapping tracks because you have most of the work already done.

Just because a sled has been properly maintained, it doesn't mean that a bearing will not begin to fail during the very next ride. I check them in the condition they come out, then pull the seals and check the lube, then I clean with carb or brake cleaner, recheck for wear, and only if all is well do I repack, install seals, and reuse. I have just had too many surprises through the years to take a chance.

Easy to replace with chaincase off. Real hard to replace along the trail, or deep in the hills.

Incidentally I am using different bearings with metal seals (shields) this year for both jackshaft and driveshaft on a several sleds. I don't know how this will work out yet.
 
Ding -> What are the pros/cons to using the metal seal bearing v/s rubber? I had to put a few in my rear suspension due to lack of availability of the rubber sealed bearings. Just wondering what prompted you toward the metal seals.
 
Another thing I encountered was that the bearings in the chaincase had been installed with the seals on the outside, (away from the chaincase) therefore letting all the metal shavings into the bearings. I wasn't too happy about that!
 
cajones2 said:
Ding -> What are the pros/cons to using the metal seal bearing v/s rubber? I had to put a few in my rear suspension due to lack of availability of the rubber sealed bearings. Just wondering what prompted you toward the metal seals.
Click to expand...
Strictly availability. I can get them easier. I did not research the engineering data beyond the fact that they were the same dimensions and rated similar. No idea if they are better or worse. They may rust, I don't know yet.
 
Ok, I got my wife's driveshaft out no problem (500, just two drive cogs). Now my 700 (with 4 cogs) is a bit more of an issue! I can't budge the set screws! I've had them soaking in penetrating oil for HOURS! I went and bought a 3mm T-handle allen wrench, and still nothing! Anyone have any advice to get those out?!?!?

Thanks!
Mike
 
Usually a little heat from a propane torch is all you need. I use Blue (medium) Loctite on mine. When changing for the 1st time, they always need heat to loosen the factory Loctite. I've had the best luck with a 3/8 ratchet and an allen socket. Good luck !!
 
I would change the bearings. much cheaper now than in the future. Heat should work as well. I always warm them when they are tough to twist.
 
I would replace. Not so much on mileage but age. Like said before heat with torch and try set screws. If they strip, then you'll have to drill them out.
 
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