Airhead: quirky is as quirky does.

[tsa]

Many OEM saddlebag brackets have broken and been re-welded.

Apologies for a slight thread swerve, but whilst preparing candidate twinshock rear subframes for a ground up build, I recently noticed both had cracks at the same location, at the weld of the front top crossmember where is welded to the right side top tube. See picture. So far I've had the opportunity to examine one other subframe, which was cracked at the same spot. This must certainly be a known (at least to someone with more airhead experience than me) weak spot ?

Subframe cracks 513b.jpg (96.46 KiB) Viewed 1985 times

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To direct the thread back on track, I can perhaps add another one:

Location of fuses on (twinshock) airheads, most annoyingly on RS/RT faired ones - for some reason the Bavarian engineers hid those fuses in the most remote place they could think of; behind the fairing headlight glass, then behind the headlight, and then camouflaged at the back of the headlight shell behind lots of multi-coloured wiring. I am sure the engineers insisted on black fuses, but was out-voted by the standardisation officers who pointed out that 8-Amp fuses simply had to be white . . .

[Bamboo812]

Has anyone mentioned the butterheads yet...?

[ME 109]

This must certainly be a known (at least to someone with more airhead experience than me) weak spot ?

My subframe cracked all the way through there as well. I re welded it and it hasn't cracked again.
I left the crack unrepaired for quite some time, observing it. There is very little movement at that point, judging by the lack of any evidence of the two sides of the crack rubbing together. Easy fix.

[khittner1]

To TSA's "thread swerve"---I think I remember that cracks to the twin shock bikes' seat subframes were associated with stress caused by the earliest saddlebag carriers, which lacked the legs that bolt to the passenger footpeg brackets. The only connecting points with these earliest saddlebag carriers were at the upper shock mount on each side, and through the bolt "tunnel" at the back end of the subframe; the carrier "loops", that the bags buckled to, essentially hung free, without any other supporting tie-in to the motorcycle frame. This arrangement torqued the top of the bikes' seat subframes, causing cracking, perhaps as you're finding.

On the later bag carriers, the joint, where the lower legs connect with the main carrier "hoop", would frequently break when the bags were overloaded (as the bags' volume and convenience tend to facilitate), hence, my comment on that oft-seen failure and repair.

[Zombie Master]

Has anyone mentioned the butterheads yet...?

I thought that was a /2 thing.

[tsa]

This must certainly be a known (at least to someone with more airhead experience than me) weak spot ?

My subframe cracked all the way through there as well. I re welded it and it hasn't cracked again.
I left the crack unrepaired for quite some time, observing it. There is very little movement at that point, judging by the lack of any evidence of the two sides of the crack rubbing together. Easy fix.

Ahhh, many thanks, ME 109, for observing and noting the lack of movement at the site of the crack. I'll get my subframed welded, and then leave them in peace.

Considering, and acknowledging khittner1's comment, could you add if you carried much extra load, such as a pillion, or very full panniers before you noted the crack, or the lack of rubbing?

[melville]

I like the sigh mine makes on shutdown. Here's that sound after the first ride:



Click the image for the vid.

[SteveD]

Send the buyer to one of the websites that have this info. Suggest that he read for a long time before riding it. Suggest that he go to a forum like this one before starting to "fix it." Asking is free.

Rule #1, keep your money in your pocket. Avoid dealers.

John has the link Duane.

[SteveD]

Thread could also be titled, "They all do that sir"!

Another spot where I've seen a crack is on the left side, the mainframe triangular gusset that the muffler is bolted to. The crack can happen at the top and forward, close to the rear main frame down tube.

The one that's annoying me at the moment is the tail light has a mind of its own, only working occasionally. All looks good and the bulb is new.

[khittner1]

Considering, and acknowledging khittner1's comment, could you add if you carried much extra load, such as a pillion, or very full panniers before you noted the crack, or the lack of rubbing?

ME has previously posted photographic and video evidence that he rides his robustly loaded RS in a spirited manner (I.e.: like a bat-out-of-hell pack mule). A bit of welding rod was the least he could do for the poor thing . . .