clunking noise in drive-drive or rear-end

Last weekend is did some minor maintenance on my 2004: replaced the front tire, changed oil, changed rear drive oil, replaced front pads. I drove the bike to work Mon and Tue with no issues. Wed the rear brake pads come in and I replace them. I was a little unsure that the left pad had seated correctly even though I was able to get them both bolted in. With the bike on the center stand I rotate the rear tire by hand, nothing out of the ordinary. I decide to test with the engine and it in gear. I start up the bike in neutral, all is good. I put it in gear and slowly let the clutch out and I hear a clunking sound. Not sure if it's coming from the rear tire or the engine. I shut it down, check the rear tire again, all seems good. I decide to not ride the bike until I find out what is going on.

Fri evening I do the same test and get the same result. I increase the rpm and it seems to either go away or is happening close enough together that it is less noticeable. I go through all the gears and get the same result. There isn't any more felt vibration than normal. I take a slow ride down the street and I don't feel or hear anything. NOTE: I have my helmet on and the whine of the engine is covering any other noise.

After reading some posts I decide to take off the rear tire to see if there might be something noticeable. I had read somebody had a similar problem and it was the cush-drive?? Not sure what that does.... I don't see anything obvious i.e. broken, metal shavings, etc. All the bearing feel smooth.

I also remove the final drive and it feels ok as well.

All that said, this is the first I've torn into a shaft-drive.

Any suggestions / thought? Questions or direction to go next?

thanks, as always for all of your help and input.
GJ

jillsogw said:

I put it in gear and slowly let the clutch out and I hear a clunking sound. Not sure if it's coming from the rear tire or the engine.
GJ

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Are you sure it's coming from the rear of the bike? I would guess that if it was not there before you changed the pads, and is there now, you probably did something wrong. Just in case, check this out (my thread) LINK.

Gj.... drag the rear brake and the sound will likely go away. The drive train has clearances (they're built that way), and running it without load means the rear wheel will rattle back and forth within the clearances that exist between all the mating surfaces of gears, splines, etc. (Aka 'lash'). Normal. If you search, you should be able to find quite a few others who've been surprised by the same thing.

There's also a few threads which show measurements of the total rear wheel rotation amount that can be typically found when measuring the lash (engine off, bike in 1st gear). As I recall there's typically 1.5" to 2" of total circumferential movement of a mark on the tire--all due to normal lash.

BakerBoy said:

Gj.... drag the rear brake and the sound will likely go away. The drive train has clearances (they're built that way), and running it without load means the rear wheel will rattle back and forth within the clearances that exist between all the mating surfaces of gears, splines, etc. (Aka 'lash'). Normal. If you search, you should be able to find quite a few others who've been surprised by the same thing.

There's also a few threads which show measurements of the total rear wheel rotation amount that can be typically found when measuring the lash (engine off, bike in 1st gear). As I recall there's typically 1.5" to 2" of total circumferential movement of a mark on the tire--all due to normal lash.

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Yes, I did try dragging the brake. The clanking was the same. Not sure if I mentioned this before, it only happens when in gear with the clutch engaged.

SMSW said:

Are you sure it's coming from the rear of the bike? I would guess that if it was not there before you changed the pads, and is there now, you probably did something wrong. Just in case, check this out (my thread) LINK.

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I'm not positive where the sound is coming from. It first seems to be at the rear of the bike. It could also be forward near the rear of the engine and swing arm area. It is definitely on the right (shaft) side of the bike.

Have a look at post 18 on the first link below. It has a video of what a bad U-Joint sounds like.
Hope this helps in your fact finding.

https://www.st-owners.com/forums/showthread.php?53437-ST1300-U-joint-Remove-Replace

https://www.st-owners.com/forums/showthread.php?46961-U-Joint-Experts-Suspected-U-Joint-Failing-152K

I listened to the audio Mellow posted when his u-joint was going out. Mine doesn't make any sound when I turn the wheel manually. However, when it is in gear the sound is similar. The sound isn't at the same rpm as the engine, I'm assuming that would be the case after the transmission?

I did not realize that you heard no noise while riding, and this is entirely when the bike is on the center stand. I echo BakerBoy. When I installed my GPI (gear position indicator) I had to program it by running it in gear on the center stand for a few seconds in each gear. I nearly leapt off the bike because of the clanking the rear wheel was making. Moving the wheel by hand (engine shut down, of course) revealed a lot of lash in the drive train from gears thru U-joint and final drive. Applying a bit of brake solved that for the programming, and my bike was quiet on the road.

Not to change the topic too much...

Now that I have the rear tire and rear drive out is there any preventative maintenance I should do?

As part of the trouble shooting, what issues might I have if I put the final drive and run it w/o the tire? Would the lack of load cause any problems?

jillsogw said:

Now that I have the rear tire and rear drive out is there any preventative maintenance I should do?

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Did you check these 2 rear flange final bearings.
Post below show some nasty ones.
Do they feel notchy.

https://www.st-owners.com/forums/showthread.php?55014-ST1300-Rear-Flange-Bearing-Replacement

Yes, check all rear wheel bearings and clean and re-lube the splines using the Honda specified moly paste. Also check your rear brake pads for wear, especially if it's uneven, indicating it's time to lubricate the caliper slides. There are lots of posts on the forums about these items. I suggest using the forum search to get more details.