F800GS - RXV Shiver'ed Fork Conversion

[Ilipo]

With a good guidance from -W-

As also written somewhere earlier, the trick is to get the fork tuned by some suspension guru... Mine is still not done and I must keep the compression dampening all the way open. Otherwise the fork is too stiff/slow (atleast for me)

-Ilipo

[PenultimateMan]

Do you mind me asking how much it ended up costing in total? AltRider's got a kit on his website for Öhlins cartridge inserts for something like $1800, but his description of the adjustability is vague, and that price seems WAY higher than what the total cost of this job should be.

[epicxcrider]

Haha I'm still alive. I didn't have time to do the conversion before my trip and I spent the past three weeks riding it from California to Maine :)

Conclusion: the fork needs to be upgraded and that's my new priority but I gotta write a trip report first :)

Also my advice to anyone is put a few thousand miles on it so you know exactly what you want to change.

[Ilipo]

Originally Posted by PenultimateMan

Do you mind me asking how much it ended up costing in total? AltRider's got a kit on his website for Öhlins cartridge inserts for something like $1800, but his description of the adjustability is vague, and that price seems WAY higher than what the total cost of this job should be.

It think the total cost was apprx. 600€ as I did not have to pay for the machining... I assume it's going to cost me another 150€ to get the fork fine tuned...

The majority of the cost comes from the donor fork... So you might want to spend some time to find a good (and cheap) fork. Mine came from BMW G450X which requires bit more work than Aprilia RXV fork. In principle all the details can be found from the earlier posts.

-Ilipo

[Gangplank]

Mine work great.

If I recall correctly
Forks were $150
Shipping $25
Machining $125
Fork Tuning and revalve $200? (I did this on a trade with the guy)

So that is about $500.

It really is not as hard as it sounds. If you can find the RXV forks and find a machine shop to do the work the rest is a good suspension guy.

[Ducksbane]

I did do my forks using my left over XChallenge cartridges. They have a spacer to reduce travel to about 245mm. There is no machining, you just change the cartriges.

Very impressed as cost was minimal as I had the cartridges already. I think the XC internals suit the 800GS better than the XChallenge ... great improvement on and offroad. Used my left over Hyperpro springs with a spacer for the extra travel. This is the only fault I notice ... forks top out at full extension a little bit, so I might try different spacers one day.

[PenultimateMan]

So if you just took the cartridges, I would imagine that the forks aren't adjustable. That hasn't been a problem for you, I take it?

[Ducksbane]

Originally Posted by PenultimateMan

So if you just took the cartridges, I would imagine that the forks aren't adjustable. That hasn't been a problem for you, I take it?

The XChallenge cartridges are adjustable .... sort of !

In typical BMW style the XC has cheaper more compromised fork internals compared to "proper" Shiver internals. That being said, they aren't as cheap and crappy as the F800GS bits. They have proper compresssion damping adjustment on one fork and a more limited rebound adjustment on the other. Both adjustments are on top of the fork like the rebound adjustments on "real" shiver forks. Therefore you don't have to machine the fork bottoms for the compression adjusters and they literally are a drop in mod. The best part about them compared to the original 800 cartridges is that they appear to have hydraulic bottoming circuits so that I no longer have that terrible crashing, clunky bottoming happening.

It would have been very cheap and easy for BMW to have used cartridges like the XC (and HP2) ones in the F800GS. Some people would have found that they weren't good enough, but most people would have been happy, and they would have had some adjustment to play with.

YMMV as they say, but I'm pretty happy with the 800's suspension now. The rear (with Hyperpro progressive spring) is now the weak link, but I'm not sure I could really justify big, expensive changes at the moment, it all seeems to work pretty well. THe suspension people who did the work for me have a rebuild with modification for the rear shock, so maybe I'll go that way later.

[Gangplank]

Originally Posted by PenultimateMan

So if you just took the cartridges, I would imagine that the forks aren't adjustable. That hasn't been a problem for you, I take it?

Mine are the RXV so they are adjustable, but still once dialed in I rarely touch the adjusters.

[Gangplank]

Nice one ducksbane. Sounds like a good fix

[BDevilGS]

Hi.Can I use the fork internals from Husqvarna TC 570?Thanks,Bernard.

[Gangplank]

Originally Posted by BDevilGS

Hi.Can I use the fork internals from Husqvarna TC 570?Thanks,Bernard.

According to this site: http://www.esuperbike.com/new_vehicl...anufacturer=40

The 2001 used the 45mm Marzocchi inverted hydraulic fork with adjustable compression and rebound damping, 12.6 in travel.

Looking earlier in this thread:
From what I can find online http://slorider.com/Aprilia/manuals/Specifications.pdf the travel of the RXV Marzzocchi Shiver forks I used was 298.5 mm (11.75 in).

The stock BMW's are 230mm or 9 inches. I gave this info to the guy who revalved my forks and he was able to make a spacer to shorten them to the stock length and travel.

I believe it was a 40mm spacer spring + a 10mm solid spacer (~2"). So the 11.75 was reduced to close to stock.



So to answer your question, yes you should be able to do it by using a spacer to shorten the travel from BIG TIME offroad travel to dualsport range of the BMW.

[BDevilGS]

Many thanks.This is what I needed.

[bikecat]

Dear Gents,

I have been following these threads as I am keen to also improve the handling of my MM. Yes, not quire parallel universe but we share the same forks. :)

The MM is a tall bike and I cannot say that I am tall, so the Wilburs lowering fork springs are attractive. They also do 2 for the F800GS as well - (part number: 600-0325-08 and 600-0326-04). I bought the ones for the MM and amazingly these springs are longer than the stock ones (left one is stock):



What is interesting is that while the BMW manual prescribe an air gap of 80mm, the Wilburs prescribed one of 175mm, more than double. The mechanic who installed the Wilburs mistakenly used 80mm and now the bike is higher than stock, and the front seems harsh. I will install the recommended gap of 175mm, and keep you posted on the outcome.

Sorry if I had hijacked the thread, but I thought you guys might be interested in this.

Cheers

[BDevilGS]

HI. The inners from my Marzocchi are 930mm long,BMW inners are 890mm long.How can I make a proper size?Thanks.
https://picasaweb.google.com/1006861...04381174028770