Middle gear adjustment-- easy and effective

Do you have notice more the normal clunking coming from your tranny or what sounds like rear differential or U-joints? Could be your middle gear needs to be shimmed down a bit. Did that to my bike and made a big difference. My 2004 FJR1300 has 82000 miles and was getting a little loose.

Did you take photos, that would be an interesting share if you did. As it is a quite involved project from what I hear.

Takes about 15 minutes. Three bolts, slide out old shims and install new ones-- literally. Look at the U-Joint cover and you will see three bolts- The shims ( two of them) have a tab for you to grab with some needle nose pliers and just pull them out, Since you will install thinner shims the new ones will go right in and tighten down. Be careful how tight you make the middlegear though, it needs .004 of backlash (play)-- remember it's a differential just like your final drive. A little play is all you want and your good. I shimmed down from .50mm to .15 mm and worked great. Just order the shims on-line right from the microfiche for about 5.00 a piece.

Good info.

Other than the clunking when going on/off throttle, were there any other problems or symptoms?

I'm also curious how you decided to shim the output side of the pinion gear set and not the other, since both sides are shim-able. Or did you just go with the easier side to change. It appears that moving either side would have about the same effect?

edit - I just read through the shimming procedure. It looks a little more involved than you inferred it was.

Even the measurement of the clearance is done with a special tool that converts degrees of rotation to a distance measurable via a dial gauge.

Sheeezzzzz another thing to maintain. I will have to check this out also. The clunking on the 08 is getting more pronounced. #25 I presume?

https://www.cheapcycleparts.com/oemparts/a/yam/5004608af8700209bc7951a7/middle-drive-gear

Dave

It's not a "differential", no motorcycles have them. It is a right angle helical bevel gear drive in both locations (middle gear and final drive gear).

I would want to know why there is bearing play that needs adjusting. Typically, these gear setups are good for an indefinite period unless something has happened to them. Never had to do this on several shaft drive motorcycles I've owned over the past 35 years or so.

Dan

I always thought the occasional clunk, usually from ham fisted shifting, came from the shock absorber wachamacallit in the output shaft..??

bergmen said:

It's not a "differential", no motorcycles have them. It is a right angle helical bevel gear drive in both locations (middle gear and final drive gear).
I would want to know why there is bearing play that needs adjusting. Typically, these gear setups are good for an indefinite period unless something has happened to them. Never had to do this on several shaft drive motorcycles I've owned over the past 35 years or so.

Dan

Click to expand...

Some folks baby thier bikes, some don't. I am in the latter group.

Good day,

Dave

proper name for the shock absorber wachamacallit is cam drive - two interlocking spring loaded cams...ostensibly to reduce shaft drive jacking and jolts from bad shifting..

...and the cam gear is part of the Middle Gear assembly.

The reason is shimmed the middle gear is that I was hearing alot of noise going on and off the throttle down by the u-joints. I replaced the u-joints but they were good. When I had the swingarm off I twisted the output shaft back and forth and found more than usual play, and nice metallic sound when doing so. As far as the .004 play, if you can feel a little play back and forth I think your darn close.

#25 ??

If it isn't broken don't fix it. There is a shit ton of FJR's out there with many hundreds of thousand miles on them that are untouched. This seems to be nothing more than something for the type A personality's to worry about. Just ride the damn thing and don't worry. Just my opinion and it's worth what it cost you.

mjlovstrom said:

#25 ??

Click to expand...

Click on the link in the previous posting of mine and I assume #25 is the shim that you speak of, correct? Ray, I won't be getting to this any time soon. I have enough going on with the 2015 to keep me busy for the time being.

Dave

Ray, you underrate yourself. Your opinion is worth AT LEAST twice what it cost!!

I'm also in the "Don't fix what doesn't need fixing" camp! It's a little like anything from "Trooper mod" to coolant change "Blow jobs". If it makes you happy, don't let me (or anyone else) stand in your way.

For what it's worth, it is interesting that a change in a shim can make a big difference in the "clunk". Perhaps Yamaha has tightened up their specs with the GenIII+ - I am told that the "clunk" is less with the newer bikes.

Nice replies, just started hated to ride my bike with it clunking every time I shifted--- Type A mabey, but not deaf. It was a fix worth 30 minutes of my time and 20.00.

I'm an Auditor-- go figure

Hey Dave, yup # 25 on the ficsh are the shims--- Actually only less than 3.00 each--cheap

I've heard the shims must be double medium 56 bernie offset. I have not done it to my bike.

The "clunk" that would come from the middle drive (if it was too slack) is not the same as the "kerchunk" that comes from shifting into gear from neutral. The kerchunk is caused by the freewheeling driven side of the clutch being suddenly stopped by shifting into gear. It is caused by the inherent clutch drag and is seen in all FJRs to somewhat varying amount. Lots of previous discussion about the kerchunk, so we don't need to rehash that now.

The "clunk" the OP said he had would occur mostly when you were riding along and open and close the throttle, similar to what you would expect with a sloppy U joint. I can see how he would mistake it for that especially since it would emanate from the same area on the bike.

I can't recall anyone ever reporting having had a failure of the middle gears, which is pretty telling that this area doesn't really need to be messed with except for personal desire that everything be just right. But, if you do mess with these shims and leave the gear clearance too tight you would cause damage to the bevel gears, which could be pretty disastrous.

Best to know what you are doing when setting that clearance. That minimum clearance is there so there is no gear binding and excess friction as the parts heat up and expand during use. If you did the math you could convert the clearance spec to a degrees of rotation and somehow make the adjustment that way. Or you could fab up the special tool shown in the FSM to make the measurement with a dial gauge. Just my opinion; setting that clearance by feel is probably not the best way to go. YMMV.