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final drive play


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1999 rt 23,000mi. Decided to check rear dif today (12-6)(3-9)rear wheel play,used a dial meter and have 1/64 inch play at outer rim area in both 12-6 and 3-9 position. Have read no play is acceptable is this correct should I be looking at pulling diff apart.Have changed oil 2x in 6000mi to check for contaminants oil is clean. thanks

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Morning Kamlooper


That is difficult thing to evaluate over the internet.


The final drive in your bike is designed to have a pre-loaded crown bearing so technically there should be no play what-so-ever. Bearing “preload” is (0.00197_to_0.03937) mm. Key word here is PRELOAD.


But there are a bunch of variables that can come into play.-


First off- when measuring at the wheel rim it is very difficult to mount a dial indictor to ONLY show bearing movement as the indicator is either mounted to frame or at the very least a long distance from the bearing itself. SO, you get not only the bearing play (if any) but also rear wheel deflection and pivot bearing play figured in. Then you get the lever arm effect of a very slight amount of play at the bearing being magnified by the measurement distance from center. Then you have the force put on the wheel rim (how hard you pushing and pulling?)


Can you determine if the entire movement is at the crown bearing itself or do you also have some rear control arm movement due to pivot bearing play (front pivots or rear pivots or both).


Usually on a loose crown bearing you can physically feel the thing clunk as you manually move the wheel at the rim area.


If it is in fact all crown bearing play then you should re-measure it after a long ride while hot. If it is still loose on a hot final drive then you will have to make a decision to either keep riding it and monitoring the wheel free-play, also monitoring the gear oil for SHARP metal particles, or pull it apart and inspect the crown bearing and off side tapered bearing, then if the bearings are OK re-shim it or replace the bearing(s).


If the bearing ball separator is still in good shape, no sharp metallic pieces sticking to the drain plug magnet (if you have one), & no sharp pieces of metal in the gear oil itself then you are probably looking at a little bearing wear on both sides. That can still give you many many miles of riding without failure.


That’s a tough call on what to do. I rode my old 1100 for better than 20,000 miles with a similar loose bearing and when I pulled it apart I was thinking I would find a smoking gun bad bearing but no bad bearing or pitted races, just a little loose. I did replace the crown bearing with a new on but kept the removed one for a carry along spare as I could find no issues with it.


If you are planning a long trip you might at least pull it apart for a look at the crown and off side bearings (you can do that with the final drive still in the bike). You can either replace the bearing and re-shim (can be done at home if you are creative), or if the bearing(s) look OK just go up a shim thickness and re-assemble.


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Be sure you are measuring backlash not just deflection.


Assuming you have backlash, get someone else to apply the 3-9 and 6-12 moments to the wheel rim and use a fingertip spanning the relative motion gaps to detect where the backlash is occurring. You will have to place your finger in the relative motion gap of each bearing to figure out if the backlash is linkage based, or crown bearing based.


A fingertip can detect very small relative motions. No need to use a dial indicator. If necessary put the transmission in gear and rotate the back wheel slightly to load things up so you don't get confused by slight rotation instead of backlash.

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Matt, Kazoo

I'm betting it's the final drive pivot bearing. I had the same play in my rear wheel. I removed the final drive, swingarm, and driveshaft. All were OK except the pivot bearing. Two needles were already out of the bearing and a third was detached on one end. Replaced that bearing with a bushing kit from Rubber Chicken Racing and all is well again.

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thanks for responses, I dont think play is in pivot bearing as I get same amount of play no matter where I grab wheel, will check after long ride today. Bought bike last fall with 17,000mi on it serviced at dealer since new , changed oil in final-tran and engine rode 3000mi changed again just to check all oils for trouble than changed all oils again after 3000 mi before storing for winter oils all clean. I am a little anal when it comes to bike maintanance that in it self might be the problem.

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rode for a couple of hrs today than checked for play few minutes after ending ride,no play at all, thanks agian for responses

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Afternoon kamlooper


That is good news as that pretty well eliminates the pivot bearings and swing arm compliancy.

With it getting tighter when hot that means that for most riding you are running with somewhat 0 play bearings. Sounds like your crown bearing shimming was at the minimum when built then a little wear took it into slightly loose when cold.


Personally on the 1100/1150 final drives I would rather have it slightly on the loose side than tight side. The 1200 final drive actually gives you a loose bearing cold but that has a different style free floating R/H bearing, yours is a tapered roller on the right so is designed to work with a bit of preload.


Maybe just monitor it occasionally and if you start to see a little play when hot maybe go in and check the bearing and if OK just shim it a little tighter. You won’t even have to measure the preload as you know you are a bit loose now so if you don’t add more than the max range preload thickness to what you have it can’t be too tight.


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