Clunky Commando

swooshdave

swooshdave

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Apr 2009
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Long time listener, first time caller...

Ok, that last part is a blatant lie. :p

Short story to bring everyone up to speed before getting into the clunkiness. I've still been riding my Commando, to occasional club events or when I can get @Mike T to get out of the (Mighty) Garage. But I certainly haven't been working on it much. I've been wasting most of my time in the woods of the PNW (of the US, you dang Aussies) instead. And more recently I've been put on an unplanned sabbatical, more formally known as: I've been laid off of work. Only 23+ years at Nike and shown the door. But don't feel bad for me, it's happened to way better people than me.

So now I have more free time and will be haunting this place again. Sorry about that. I'm a wee too young to formally retire so I'll have to earn some money until I get as old as some of you farts. Ok, enough backstory...

I don't really ride on the freeways much, more just toddling along the backroads but the last couple times on the freeways at about 70mph indicated (probably more like 65 actual) there's a discernible clunking. Not enough for me to stop the bike and walk home but certainly a new sound. It feels like from the rear end, which means it's probably from the front. :confused:

So with the additional free time I've torn into it. And here's the story so far.

Victim/Patient: 1973 850 Interstate

Clunky Commando

We just had a ride to a museum (actually it was an awesome ride with an incredible turnout, video one of these days) and when I got to the start point (also an incredible location) I looked over the rear of the bike and noticed the nut holding on the rear brake arm had gone AWOL. Luckily our host has a substantial collection of random nuts and I was able to secure the arm down. Alas that was not the source of the clunking as I found out when we set off.

Clunky Commando

So back home the rear wheel came off for a better view. And to clean. Don't worry the rust prohibitor will reapply itself.

Clunky Commando

Stub axle moves around but that's normal. Strange but normal.

Clunky Commando

Chain guard is unfortunately broken which is a shame as that's a nice chain guard, aside from being broken now.

Clunky Commando

Relatively low miles on the speedo drive. The end doesn't spin but it wants to. Not sure if I'll be able to fix this. I swear these things have the life expectancy of a fruit fly. And this one was supposed to be the best quality out there.

New post as I think I'm limited on the number of images.
 
Clunky Commando


What's this? The rubber isolator bolt is hitting the swing arm? It's not hitting by much but it's definitely hitting.

Clunky Commando

My new favorite tool, a cordless die grinder. No more having to fire up the air compressor. Just lovely. Spins to like a billion rpm.

Clunky Commando

Within a couple minutes I removed about a tenth of an inch, which is plenty.

Clunky Commando


Clearance established. Not touching.

So I start grabbing the swingarm, looking for other sources of the clunk. At first I thought the swing arm is moving to the side, which would be surprising as it's been clamped. Upon more careful inspection I now think the play is in the rear isolastic.

Now I need to revise and remember if the rear iso can be addressed in the bike. I don't think it's the Mk3 type but I do recall buying a set of Mk3 isos for this bike with the grand intention of installing them on of these days. Maybe that day had come.

Anywhere else I should look for the clunk? I'll try to get a measurement of just how much the rear end is moving to the side later.
 
Chain looks dirty n' dry .
Good chance to regrease the double row hub bearing too .
Clunk could be a worn chain that hit the chainguard , breaking it .
 
My first thought were the cush drive buffers.
You have the wheel off, what are they like?
 
Wheel bearing maybe gone. Has the wheel got side play when bolted up? Mine disintegrated a few months ago. Clunk clunk. The spacer between the bearings was possibly not the right length causing side load on the bearings. Graham
 
velo54 said:
Wheel bearing maybe gone. Has the wheel got side play when bolted up? Mine disintegrated a few months ago. Clunk clunk. The spacer between the bearings was possibly not the right length causing side load on the bearings. Graham
Click to expand...
That is something I will definitely be checking. Although initially impressions are that the bearings are fine.
 
glad to see you back Dave. Some simple things to check first would be rear chain tension (clunking could be chain whacking inside of guard), and tthen try to get a grip on the countershaft sprocket to feel for any play in the sleeve gear bearing
 
"Content not viewable in your region" is all I can see where the pics are meant to be (I'm in UK )- why's this?
 
Just glad you've got some sort of problem so we get to see and hear from you again. Swoosh is back with pictures to prove it, high quality as usual.
 
Other things to consider..CS spring and or its fixing holes getting sloppy and letting stand flop about. Same for SS pivot point.

Headstead worn...oem rubber or the Taylor type rose joints.

Primary case coming in contact with left aide Z-plate...a sign of rear nickerlastic compression.
Also header pipe can work loose, rotate and contact SS frame lug at times.
 
Tornado said:
Seems SD has lost his VIP status so is posting pics on external services...some of which are blocked in the antipodes...
Click to expand...
Tornado said:
Other things to consider..CS spring and or its fixing holes getting sloppy and letting stand flop about. Same for SS pivot point.

Headstead worn...oem rubber or the Taylor type rose joints.

Primary case coming in contact with left aide Z-plate...a sign of rear nickerlastic compression.
Also header pipe can work loose, rotate and contact SS frame lug at times.
Click to expand...
True confession time, I never had VIP status. I use Imgur for hosting. I was one of those victims of Photobucket and switch to Imgur, as it hosts about a trillion cat memes that I knew would never go away. Sorry to my UK brethren, I didn't know the cats were so offensive.

And I think we have a winner. @Mike T came over and I shook the swing arm. I sure thought it was the rear isos. But with the extra set of ears he pinpointed the headsteady. Off came the tank.

Clunky Commando

Clunky Commando

Clunky Commando


I assume just take them off and measure them and order some up? Maybe I'm not the first person to wear out a Taylor? I also need to get some protection for those spark plug wires.
 
Not sure I understand about the Taylor being worn out.
It appears to me the rear isos are worn allowing more verticle movement thus hitting the bracket.
The Taylor allows verticle movement, not lateral.
Setting up my Taylor was a real pain as it interfered with the bracket.
And yes, it clunked around. Took some fiddling to get it right.
Maybe I'm wrong, Am I missing something?
 
MichaelB said:
Not sure I understand about the Taylor being worn out.
It appears to me the rear isos are worn allowing more verticle movement thus hitting the bracket.
The Taylor allows verticle movement, not lateral.
Setting up my Taylor was a real pain as it interfered with the bracket.
And yes, it clunked around. Took some fiddling to get it right.
Maybe I'm wrong, Am I missing something?
Click to expand...
The video is not clear (my bad) but there is significant play in the Heim Joint. Like a lot.
 

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