Final Drive gears

mlheck said:
I just happen to spend 8 hours a day lapping ring and pinion gears together to form this matched set that you speak of.
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Thanks for all the info Michael. A voice of experience it seems.

A little more explanation on my end: Bought a 91 which turned out to have no splines left. I took everything off the rear of my crashed 99 except the swingarm and temporarily transferred it to the 91, so that is now my working bike.

Now I need another final drive to hopefully get both bikes running and got one that had been in Hurricane Katrina (the price, cost of shipping, was right, thanks Dave). A little rough on the outside with some corrosion (exterior of the pinion joint and retainer) but the inside looks ok and the splines are excellent. The choice was whether to live with the corrosion and hope it doesn't lead to any problems, or to yank the ring gear because the good splines are what I need. That's what I did and put it in the 91 drive. Turns nice and smooth!
Perhaps using the entire hurricane unit is a better choice? as I won't be able to do the stuff that you do.
Does Honda actually do this at the factory with each bikes gear set?
 
I am guessing that the final drive units are sourced from a supplier that builds them for Honda. So it would be the supplier that does this when they assemble the unit, but yes this has to be done when each unit is assembled. It really doesn't take much time when working with matched gears. The process of matching the gears takes care of allot of this. Then there are machines that measure the housing dimensions and call out the shims needed and then the unit is assembled and rolled to check the gear pattern. If the matching process was done correctly and the housing measurements are correct, then the pattern will spot on. Once in awhile a unit has to torn down and correction made. Now when this unit is rolled a good amount of resistance is applied to the part that is not being driven to simulate the load the gear set will be under when on the bike. Image 100 hp trying to move the weight of the bike and rider all through those small teeth. On most gears sets you have less than 2 teeth in complete contact at any given time. This creates a lot of pressure on this contact spot, thus the reason it has to be correct. Most modern Hypoid gear set will sound quiet when rolled without a load applied. We even have to go so far as to test roll a sample of matched gears on a machine that measure the slight rotational speed changes form tooth to tooth. This is all done in the name of NVH (Noise,Vibration, and Harshness), and we are talking full size trucks and 4x4's here. I'm pretty sure that Honda has some specs for their supplier to meet.

I haven't read any of the information that has been presented to you through links, so I can't explain in much detail what Honda is doing with their units. I am just trying to point out the complexity of a system that most people wouldn't notice or take into account. Only you can decide what is your best option, but I wouldn't break up a matched set to try and save money. It will most likely bite you in the rear. Pun intended.
 
In the automotive world most transmission shops will do it, but this will probably require you to find a Honda shop that knows how to do this. The problem comes down to the shims. You have to have a ready supply of the different size shims to make your adjustments. Finding a shop that has these may be difficult. I plan on getting some pics and putting together an article on reading gear patterns as soon as I get some time. I know that doesn't help you now though.
 
Time not an issue Michael. Look forward to your article. Bike won't be goin' anywhere soon.

I called the only two places in the local yellow pages listed under gears and they were no help.

I have both drives all cleaned up and will be putting the halves back together to get some oil in there. Just not sure which halves I'm gonna pair up. Good thing I have my good '99 drive working like a champ on the '91 !!
 
Wow! Learned a lot from these posts. Maybe too much...
I have a pair of GL1200s, as well as the ST1100.

The GL1200's have a nasty achilles heel in the rear wheel bearing housing. It is of insufficient thickness, and over time goes eggshaped, allowing the bearing to move, imparting a terrible wobble to the bike. With the wheel design, it is almost impossible to repair.
The fix (until I read this post...) is to find a GL1500 pumpkin and wheel. The GL1500 pumpkin bolts up to the GL1200 swingarm, although the mounting holes in the swingarm need to be enlarged by 1/16" each. Obviously, it is impossible to find a matched pair for things about 14 years old... As ignorance can truly be bliss, I simply put the GL1500 pumpkin (from a local wrecker) on the 1200 hack, and swap two wheels/drive flanges sourced from ebay as needed for powdercoating, new tires, etc. No problems with drive mating yet; guess I've been lucky.

Hm... maybe a slight hijack is in order with all the drive experts here...:D
I just picked up a ST1100 pumpkin from ebay, and am going to see if it fits the GL1200. While the GL1500 pumpkin/wheel/brake bracket fits and solves the GL1200 wheel braring problem, it offsets the rear wheel (compared to the front) 3/8". I have yet to get a definitive answer on whether this would create a handling issue or not...

And now back to the originally scheduled thread topic...
 
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