Splines

[Moonshot_1]

Last year took the bike to a local guy for some maintenance stuff. One of the things was to check and grease the splines. This because I'm running a car tire. He said at the time the splines were still greased up and looked fine.

A year and 13,000 miles later, I take it to a different guy. Local, former Honda/Harley dealer from years past and now owns a NAPA store in town.

Have him tear it down to check and lube splines. I go in a few days later and have a look. Well, they are pretty much toast. Big pile of rust and ground up pretty good. So getting things replaced.

Question though.

In getting the new drive shaft, he discovers that it is loose fitting in the U-joint. The joint itself looks and feels perfect but where the shaft enters the u-joint is worn considerably. The u-joint has been replaced with a new one. I should note that I did raise a concern about the u-joint before he started the work on the bike. (Had faint clicking noises on occasion)

So the question is, with the issue with the splines, is this problem with the u-joint common?

[Valker]

OK, I know this is a dumb question, but did he try the shaft in the correct end of the u-joint? The ends are different sizes IIRC.

[F6Dave]

There are actually 3 sets of 'splines' people refer to, even though technically they all aren't splines.  The U-Joint splines are usually not a problem and in reality don't need frequent attention.  I never checked mine until 30K+ miles and they still had plenty of moly paste (even though I think the manual says grease) on them.  If they were loose, is it possible someone removed the spring and clip at the front of the shaft?

The pinon cup is #2 in the path.  It does get dry and can damage the cup and driveshaft.  There are 2 schools of thought on how to maintain this.  One is to follow the manual and make sure the little hole in the cup is kept clear so gear oil lubes it.  The other, which I learned from a mechanic at a good Honda dealer, is to grease the heck out of it.  This blocks the hole but works fine as long as you service the driveshaft frequently.  It also makes it less likely that the oil seal on the driveshaft will leak.  I've used this method for well over 100K miles with good results.

The drive slines, where the final drive connects to the wheel, is where most problems occur.  The culprit is almost always inproper alignment of the final drive and wheel.  If they don't mate squarely, the splines become a kind of U-Joint, grinding against each other with every revolution of the wheel.  If the misalignment is bad enough they can be shot in a few thousand miles, REGARDLESS of how much or what kind of grease you use.  On the other hand, when properly aligned there will be virtually no wear even if there’s crappy lube on them.  I’ve seen dry, rusty splines with hardly any wear at all.  In fact you could probably use WD-40 on them and they’d be OK if properly aligned.  I wouldn’t do that, though!

The key to proper alignment is simple:  torque sequence.  When you reinstall the drive to the driveshaft tube, make sure you torque the axle nut FIRST.  There is a lot of slop in the 4 holes at the back of the tube, which means they must be tightened LAST to make sure the final drive and wheel are mated squarely.  It’s really pretty simple, but can be a very costly mistake.

[bscrive]

F6Dave is speaking the truth.  I can attest to that.  When I changed my tire a couple of years ago I didn't loosen the bolts and when I changed the tire last month, the splines were almost completely wore off.  Damage was $500 in parts.