Yamaha TRX850 Enthusiasts Forum

Shocks can be had for about $1-200 AUD, it's a good Sachs unit, spring rate quoted as around 8.5kg/mm, but from what I read, BMW have underquoted that one. Either way, possibly a little less than the R6 unit, but has hi & lo speed damping as well as rebound adjustment.

Preload is by threaded collet, so more finely adjustable than the R6 unit, I think it can also be set up with more preload than the R6 unit.

Caveat: I haven't tried it out or even made sure it will fit in the TRX yet, but I have been in touch with Kayla & have a rough price. It's a very fair price for the work required, but it's probably too much for me to wear on my own, so if anyone's interested, please let me know. If we could get 5 made, I reckon it would be worthwhile & Kayla would also have another product to sell.

yes, I could be interested, but obviously price dependent.

That's a start!

Anybody else?

yes, interested.
I am deciding between the BMW and the R6.
Price for the shocks is about the same, but I am not keen on the color, at least can get a R6 in silver... (picky bugger arent i)

knumbnutz wrote:yes, interested.
I am deciding between the BMW and the R6.
Price for the shocks is about the same, but I am not keen on the color, at least can get a R6 in silver... (picky bugger arent i)

I'd say stick with the R6 unit for now, Kayla has already done all the hard work with that adaptor.

I'm trying to design the BMW adaptor in CAD, but I'm having a hard time keeping enough metal in the adaptor & keeping it the original length

Hi MV,

I think we are looking at the adapter the wrong way.
Why dont we make two plates to go on the outside of the BMW shock with the cutout on the inside of the plates.
The bolt in the BMW shock will be longer, but the bolt into the linkage can be recessed to use the original bolt.
For the shock bolt, a simple tube on the inside of the U will stop the U being crushed when the bolt is done up tight.

Let me know if this makes sense because there is plenty of material, it would be sturdy without side or vertical play and be very easy to make.

regards Neil

if you have dimensions and pictures of what it is you want to achieve I would be interested in having a look. I have a good friend who designs complex parts for satellites and communications systems and the like who would be able to come up with a design I am sure

ok, so here is the shock.
Here is my super accurate cad (ms paint) drawing
Actually, it is very simple to make as the cut needed is just one end mill as the shock U piece is round.

I should add, I would bevel the edges and round the end. But for the sake of simplicity in the drawing it is easier to see this way.

Will this be an issue????
If you recess the plates to keep the shocky fork Inplace and stop it rotating in the plates themselves you would be relying on the integral strength of the thickness of the shocky fork material to take any lateral movement???

When the shocky fork is bolted straight on the relay arm as in std trim, any movement is taken in a downwards, upwards motion due to only the 1 singular pivot point instead of two with the adaptor plates method .
Quote Julius Sumner Cobba

Wait for it wait for it

cobbadiggabuddyblooo wrote: Quote Julius Sumner Cobba

Wait for it wait for it

Most people would remember old Julius Sumner as the man with the glass and a half. He certainly had more than the standard amount of smarts.
I hope this does not make you the guy with only half a glass?

Why is it so?

What issue ?
The beveling and rounding is for looks only. Me thinks a little prettying up wouldnt hurt.

cobbadiggabuddyblooo wrote:Will this be an issue????
If you recess the plates to keep the shocky fork Inplace and stop it rotating in the plates themselves you would be relying on the integral strength of the thickness of the shocky fork material to take any lateral movement???

When the shocky fork is bolted straight on the relay arm as in std trim, any movement is taken in a downwards, upwards motion due to only the 1 singular pivot point instead of two with the adaptor plates method .
Quote Julius Sumner Cobba

Wait for it wait for it

knumbnutz wrote:Hi MV,

I think we are looking at the adapter the wrong way.
Why dont we make two plates to go on the outside of the BMW shock with the cutout on the inside of the plates.
The bolt in the BMW shock will be longer, but the bolt into the linkage can be recessed to use the original bolt.
For the shock bolt, a simple tube on the inside of the U will stop the U being crushed when the bolt is done up tight.

Let me know if this makes sense because there is plenty of material, it would be sturdy without side or vertical play and be very easy to make.

regards Neil

Perhaps, I'll have to drag out the files, but I'm between PC's right now...

The main problem was the distance between the two mounting holes, too close together to achieve enough strength I think. IIRC, it was something like 25/30mm between centres, with 10+mm holes... Doesn't leave a lot of material. Of course we could make the bracket wider, add triangulated gussets, etc, but all that would increase machining costs exponentially.

Except if you do it same as above because the thickness over the shock would be the same as the shock U thickness thereby negating the strength issue. The hole could be directly under the Shock and the strength would be ok.
Material cost is a non issue, the aluminium cost is less than $5 for 10mm bar in the width needed.

I will make a pair for myself as I think i can probably get my hands on a mill or do it on my lathe by mounting the on the headstock and the end mill in the chuck.

dicky wrote: I hope this does not make you the guy with only half a glass?

Why is it so?

so my half a glass makes me thirsty ...
Wouldn't the two pivot points work like a chain link with the potential to kink if a downward force is applied????
Half glass due to Tim tam straw