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CX650 Final Drive Rebuild

757 Views 8 Replies 6 Participants Last post by  Desert650
New user here, first time posting but have lurked for a few years. I've got a 1983 CX650C that I picked up several years ago for a first bike. It had the usual starting clutch issue and I started repairing it the day I got my endorsement.

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A few weeks ago my final drive started pouring oil. Turns out bearing closest to the wheel failed, so now I'm rebuilding the whole thing. Currently have all the parts to do so, the specialty socket, and a spare final drive on order just so I'm not in a rush and can do this done right.

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I've already opened and cleaned it up, only problem is I can't get the pinion out.

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The specialty tool (Pinion Joint Holder 07924-ME80000) is apparently impossible to find. Without it, I'm not sure how to hold the pinion in place in order to remove and reinstall the pinion nut.

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Strap wrenches just slide and I don't want to mess with the pinion teeth, so I either need to find that tool or make one.

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That is pretty much where I'm at right now. The bolt pattern for the flange should be pretty accurate but the location of the splines I am much less sure of. Not entirely sure how to accurately measure it's center. My plan is to prototype until it fits with a 3D printer and then test it to failure. Best case it works flawlessly, worst case I have to machine it at school.

All this brings me to two questions:
Does anyone know where I can just find this tool?
If not, does anyone know how I can accurately measure the location of those splines in relation to those bolt holes?
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Welcome to the forum!
Print in a quality PETG, and it might be strong enough.
See here for a method to hold the pinnion whilst undoing the nut. It`s just a simple steel strap although you could use a short length of strong chain,too.
You`ll have to do a partial reassembly and use the drive spline from your rear wheel whilst using your lock-up tool.

If you want to go the OEM route the pinnion holder is still available.
It`s $754.
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Holy cow, that ain't cheap. I've never come across either of those links so that helps out a ton, now I know what the tool actually looks like. I might still end up making my own just to have the experience in doing so but I'll definitely look into using that metal strap method.
Check the lenght of the Spacer tube that positions the wheel . Have come across a few that are to short and over load that big bearing . My 82 Silverwing went through two bearings before Honda in Fort Bragg figured out what was wrong. When I get over Covid will go into my shop and measure the spares i have.
Up to now most of us have shopped for good used replacements rather than trying to work on final drives. I believe setting the bearing preload requires special tools and if not done right...
But I'm interested in how you do with this because old rubber is old rubber and the supply of good used ones will eventually dry up.

Welcome to the forum and welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and may or may not have had all of the maintenance necessary to keep it safe & reliable so current problem aside it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
Note that while aftermarket shop manuals are pretty much necessary for people without factory training to work on a lot of makes & models of bike the FSMs for the CX/GL500/650 family of bikes are so well written & laid out that the FSM is really the only book you need and and even the best aftermarket books are secondary references at best.

I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). The original rubber brake lines should be replaced every 2 or 3 fluid changes (= 5 or 6 years) so if your bike still has them I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).
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if you have a drawing i can 3d print then i a few different materials including nylon petg and polymax and anneal them for you
Those nuts are fricking tight, i can`t see anything printed withstanding the torque involved in undoing them.
I appreciate all the suggestions and replies. Spring break just ended so I've got to put this project on the backburner for now, but I am still slowly working on it. I'm planning on using PLA to make sure everything fits and lines up properly. After that I will start exploring how to make it strong enough to actually use. I believe the torque spec on that nut is 70-87 lb-ft but I'm expecting it to take more than that to break loose. Once I have a final design that fits, I'd be more than happy to share it.
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