I decided to do this conversion. Thanks -W-!!!!!!
The sought after forks are a pair of Marzocchi Shiver 45's. They are used on a few different dirt bikes including the Aprilia RXV 450(confirmed) & 550(maybe?), Husky WR250, and possibly GASGASS.
I found a set off an Aprilia RXV 450 that had the stiffer springs. The Aprilia has 3 spring options. Light, reg, stiff. Info is available out there on the interwebz on this. Anyway, I put up a post on a aprilia forum and had 3 set offered to me. One from Santa Cruz and two from Europe. Seems not too hard to find.
Originally Posted by -W-
Aprilia RXV, BMW G450X, Husqvarna, GasGas, & Beta have these Shiver 45 forks at least. Remember to buy model which has also compression adjustment at the lower leg (some husky's don't have it even if the forks are called "Shivers")
That Shiver Factory 45 which I used was offered as an Marzocchi's "aftermarket racing fork" to some KTM, Honda and Yamaha models. I think it is basically same fork than normal Shiver 45. It just has that black special coating at the lower legs, but you don't do anything with those lower legs anyway..
My original idea was to swap the whole Shiver fork as it is to F8GS. Reason why I didn't do it was the thing that F8GS has taller upper legs than Shiver 45 has. This basically means that tubes are more inside of others in F8GS than they would be in Shiver 45 if you would use them (=more stiffer). Also if you would reduce the travel of Shiver 45's to something like 230-250mm the over all height of the fork would be too low for F8GS.
I have my forks apart and at the machinist now. I will be posting up pics and info once I get the quoted posts moved over. Anyway, once I get the feet machined locally the revalve work will be done by Ed McCoy at McCoy's off road center in Carson City, NV. It is close to me and he is a well recommneded shop. He does a lot of pro dirt bike riders forks and seems to know his stuff. Also a Race Tech Cetner for the NV/CA so good source for parts, etc.
I had the same question as -W- above. Will ask Ed when I drop off all the parts. I am planning to reduce the travel on my "RXV Shiver'd" forks to the stock travel of 230mm. Once I talk to ed we'll see which upper tubes I choose to use. My guess is that I will stick with the stock BMW's since they are basically the same. Love to have the silver ones.... pics later.
Originally Posted by -W-
But remember that you need to have your "Shivered" the forks revalved by some professional since the damping isn't enough for the much stiffer springs that you will also need (and maybe some of you want to have really "plush" suspension damping too) . But the good thing is that they can be completely revalved and after that they should be really nice..
And I personally like the thing that after that you can also service and change the shims by your self as you like and that they are "conventional" cardridges without any gas pressure (=more durable and easier to service in my book).
I didn't take any pictures from fork internals when I did the modification, but I can take some when I am taking them apart for the revalving if needed.