Are these splines badly worn?
 

Hello, new member here. I own a 2002 or 2003 Yamaha Kodiak. Can you guys tell from these pics if the splines are ok to support a new hub? I just don't have enough experience to know. The hub is very badly worn, and it will just turn on the axle.

They look pretty worn to me, if your replacing the hub then do the shafts as well or you will be doing it all over very soon. When you have mating parts it is normal to replace both at the same time for best wear.

Thank you for your reply. It's what I expected. My Kodiak is the year prior to the IRS. How difficult is a solid axle replacement on one of these things for a guy with limited mechanical experience but who isn't afraid to dig into manuals, watch youtube videos, and just generally get his hands dirty? I do the brake jobs on our vehicles, and I recently changed out sway bars on my dodge, did my son's ball joints, replaced the radiator on my wife's van, stuff like that. I do simple plumbing around the house - install faucets, garbage disposal, repaired the dishwasher and spliced the water line on my fridge. My tools are pretty basic. Had to borrow/rent a press from OReillys for the ball joints.

Would this project be something I can likely handle? I fully realize a best guess is all you can provide.

Fitting a new axle is a fairly big job, not sure if you need a press or not. Personally I would fit a new hub with plenty of thick grease and hope for the best. You have only lost the price of the hub if it fails, and new axles are very expensive for Yams.

I'm with merryman, it's taken a long time to get to that stage and they still are serviceable. I'd go for the heaviest grease and hope for another 5 years.

Do any of you guys use Moly 60 grease on splines? Honda calls for it on their shaft drive motorcycle splines.

source for hub?
 

I REALLY appreciate the replies, fellow ATV riders. I sincerely do.

Would you be kind enough to advise me on how to select a replacement and where to purchase it? I would choose "mid-quality." As for how I ride or treat this ATV, I absolutely BABY it. Seriously. The only reason the machine has any wear at all is there was about a 2-3 year period during which I shared the 4-wheeler with my teenage son. And - as anyone smarter than I will tell you - that means it got ridden hard. I very much regret not watching the situation much closer, but that's 20/20 hindsight; nothing I can do about it now. But, I putt around on it on some farm land, and I very occasionally have to put in 4wd to get through some mud. But I do not "mud ride" or ride trails. I rarely get above 10-12mph. I'm not sure any set of axle splines will see less stress than these will now that my son has moved off to college : )

If this is seriously how you plan to ride it then you might reconsider just replacing the bushings and leaving the axles as is. With non-abusive use it will probably run for some time with just new bushings. If your going to do some hard riding and plan on keeping the machine for a number of years then replace it all.

Thank you.

It's true, I ride this 4wheeler like an old man walking around on a cane, lol. I"m the second owner, and the original owner very literally was an older gentleman who used the atv to pick up sweet gum balls in his yard and dump them in a creek down the road. It was about 8 years old when I bought it, but it was MINT condition, other than the tires were worn pretty well - probably from the pavement he drove along to dump his sweet gum cargo. My son was 14-15 at the time, and I made the mistake of pretty much cutting him loose with it. He rode it like an adventurous teenage boy will for 2-3 years pretty regular. I'll now go back to riding it slow 'n easy!

By "replace the bushings" are you referring to the hub? Because that's about all there is to it: the end of the axle, with the splines, a hub, washer, and castle nut with a cotter pin.

thank you.

Just replace the hub. It wasn't your son's fault, it is common on Quads, the splines take a lot of thrust when you turn a corner on asphalt or concrete roads, and if the hub nut isn't on tight enough, they start to move a tiny bit at each corner you take, which makes them wear and eventually fail. Honda 300s and old 420s are notorious for it. Had the last old model 420 we sold in for first service, 29hrs on the clock, one hub loose.