Some of you may remember that back in Late May/Early June I had mentioned that there was a lot of "slop" in my shaftie drivetrain, and that I was guessing it was a spline problem. Several people responded that it didn't sound like splines, but was perhaps a more serious problem in the secondary gears.
In any case, I had a busy summer lined up and didn't plan to ride too much until late summer/early fall, so I went ahead and picked up a 1980 GS1000 final drive and spline set, as well as recently acquiring a 1983 "GK" final drive (which apparently has a slightly better gear set for highway cruising). My best friend called last night, wanting to borrow the bike for a ride today and I coerced him into coming out and helping me pull the rear wheel so I could swap out my soft (and hopefully trashed) splines for the harder 1980 piece. I explained to him that if the splines weren't "toast" he wouldn't be able to borrow the bike -- We both crossed our fingers as the wheel came off.
Initially the splines looked OK, and if I hadn't already spent a lot of time learning from people here who are far more capable than myself I might have reinstalled the wheel and gone on to more expensive and unnecessary repairs. Thankfully, I learned something that other people with shafties need to know!
You MUST take the splines out of the wheel hub to properly inspect them - you CAN'T tell if they're shot without removing them.
The reason is that the edge of the splines you see sticking out of the wheel don't normally contact the mating splines inside the final drive - they protrude past the mating area and don't wear. It's only after you remove the splines from the rear wheel that you can tell if there's a problem.
Sure enough, my splines were badly worn, and that was what caused the "slop" in my driveline. Now that I have the harder "pre-1982" splines on my bike I am much more confident that I will be "good to go" for the long term. By the way, ALWAYS use a quality grease (Honda Moly Lube is a very highly rated product for this purpose) on the splines whenever the rear wheel comes off to ensure that you never have a spline failure.
Oh, one other thing ... before I installed the "new" splines I very carefully cleaned the old grease and metal filings out of the final drive splines using brake cleaner and Q-tips on the recommendation of another GS'r. If you find worn wheel splines be absolutely sure you've completely cleaned out the metal filings and old grease before you install the replacement piece. Otherwise you'll likely cause premature wear to even the harder pieces in both the final drive and the wheel.
I will try to get some pictures up in the next day or so of the failed piece. I meant to take some shots of the new splines, but in the rush to get my best friend on the road I forgot to take them before it was installed.
I believe there are three reasons my splines failed:
1. The previous owner cut some corners on maintainence (although he seems to have taken good care of the bike overall) and may not have properly lubed the splines
2. The 1982 and later wheel splines are made of a softer material than previous years, and are more susceptible to problems, especially if not lubed properly
3. I ride my fully dressed bike aggressively, so I'm putting a heavier strain on the driveline than many others do.
I'll be watching the new splines as the miles roll by, but I'm cautiously optimistic that I won't have another problem with them. I didn't swap out the original final drive yet, because the GK unit needs to be cleaned up first. Once it's ready to swap in I'll have two backup final drives - the original one that's coming off the bike (in perfect condition) as well as the 1980 GS1000 unit I bought with the wheel splines just installed. If somebody is in need of a final drive let me know. The 1980 unit is a little rough, but should be able to be cleaned up nicely.
In the meantime, I'm VERY VERY happy to be "On the road again," and extremely fortunate to have not been stranded by the side of the road because the splines stripped completely out!! \\/:-D
Regards,
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