Dog Bones

First topic message reminder :

Pulled the rear shock out today, expected to see it covered in oil and rattle like the Salvo's cup at the local pub. However it was as clean and as functional as it was when I installed it, piston pretty hard to push down and comes back under it's own steam, even mechanic at the local Suzuki dealer agrees with me that the shock appears ok. BTW the spring is in good nick as well, but I will be looking for a heavier duty replacement.

The issue was the dogbones, in particular the left one, it had snapped, and the right has a bend in it near the bottom end probably due to it taking all the load.

When I was installing the Busa shock I was toying with getting new dogbones made. As I needed to gain an extra 6mm length to drop the rear down to the pre-busa height I didn't think filling and redrilling would have been wise as it pit the mounting holes too close to the end. The engineering shop I took them too said they could cut & reweld and it would be as strong as the originals, so I took that option - as I had arranged a barter and swapped them a set of adjustables for the work, everyone seemed happy.

I believed the dogbone broke near Port Campbell on the GOR, that's about when I noticed it bottoming out and thought to myself the shock had blown a seal and lost its oil and/or nitrogen.

I haven't take a photo of it yet, but interestingly the break wasn't where it was cut but a couple of millimeters closer to one end away from the weld, its a jagged tear rather than a clean snap, the other side's weld appears to be ok. Strange the symptoms all pointed to a stuffed shock, you could sit on the bike and the suspension would sag but not return when you got off, however you could lift the rear of the bike up by the pannier holders and it would come up and stay up until you hopped back on again.

Here's hoping that it is only the dogbones and no other damage has been done by riding the final 200 road kls to get her home.

I picked up the 6mm thick stainless steel dog bones, but am waiting on a new 17.9kg/mm spring to arrive before putting the Busa shock back on.  

I thought when first changed the shock that all I need to do was to get the bike sitting where it was prior to the change, but then I started looking into things deeper and peeked into the black magic of suspension geometry

barry_mcki wrote:I picked up the 6mm thick stainless steel dog bones, but am waiting on a new 17.9kg/mm spring to arrive before putting the Busa shock back on.  

I thought when first changed the shock that all I need to do was to get the bike sitting where it was prior to the change, but then I started looking into things deeper and peeked into the black magic of suspension geometry

mmmm...Are we...changing Counter Levers or something,
to allow for different stroke/travel between the two shocks???

Picked up the new spring today, looks nicely made (1000 lb/in from Eibach), it is 202mm free length (red spring), the standard Busa (2nd Gen) is 208mm (black spring).  Just placed it on the shock to show the difference, it also has collar insets due to it being slightly larger inside diameter of the coils:



I read somewhere the recommended pre-load on the Std spring was set so that the spring would be 187mm (compressed 21mm), this gives a figure of 275kg before addition spring compression takes place.  As this new spring is 6mm shorter, a 187mm compressed length gives a pre-load of 268kg (as it is only compressing 15mm on the red spring).  This is only 7kg difference which is less than ½mm compression of the Eibach spring, so close that it is within any tolerances I could measure, essentially these two springs are the same at standard settings, the red one coming into its own once addition weight is placed on the rear end.

So to get back to you MT, the queries I have been trying to figure out is if I want to dial in an additional 100kg of pre-load (i.e 5.6mm of extra compression, 20.6mm total) what if anything is that going to do to the ride height ?  Should the damping be made softer or harder or opposite (compression vs rebound) ? And will the new dog bones still bring the rear ride height back to where I wanted it.

I'm trying to keep the ride height unchanged as it would mean no changes required in the posture of the bike. I'm not game enough to tackle any changes to the Lead Link front suspension, the only thing Bandit on the front of my bike is the triple tree and brakes.

So I think this is going to be another round of sux-n-see, I'm glad I've got a smooth surface garage floor as I think I'm going to be spending a bit of time on it getting things sorted.

Its all fun and games mate.

The more "One" tinkers... The "One" knows.

There`s always going to be that personal choice in setting it up.  You can do the theory, but until you get it on the road,
and start playing with the dials, you won`t know what`s best, then to contend with Australia`s lovely roads,
one setting won`t do all.  This is why I spent $$$ on a full adjustable rear, but I`m let down by a primitive front end.

I`ve got a nice set of 07-08 GSXR1000 folks to go on mine, but still haven`t done the proper nutting out,
 in the big picture, geometry set up, of customized Triple Clamps to cater for the correct Rake, Trail, and Offset dimensions.
to give me a nice starting point.  
One day....

Barry, have you spoken to srk about it? Normal suspension static sag is something like 30mm on a non sidecar equipped ride. It's a pity you didn't get a remote preload adjuster similar to what's on the vstrom as you can change it on the fly without tools and without having to resort to rolling on the ground. I know cogent do an aftermarket collar, but it's around $400 landed from the states

There are a couple of companies making air adjustable rear shocks for the Busa, I think they are about the same price as the remote pre-loaders, and if I can find something to also go on the third wheel.....