To those who have put modern forks on your R100GS... I need help!

[Phreaky Phil]

Originally Posted by SOLO LOBO

Think this is the one!

http://www.cti-fahrzeugtechnik.de/epages/62164450.sf

Thanks Solo, I had a look at there site but couldn't find and triple clamps. Maybe they are made to order ?

[AntonLargiader]

I've read a few of these threads and I'm trying to figure out some basic compatibility stuff without having a lot of experience with what forks were used on what bikes during what years.

Which steering stems have the same diameter as the BMW ones (ergo can use stock bearings) and which ones can be used with other readily-available bearings? For instance, are all KTM stems the same diameter?

HPN uses the 50mm Magnum fork for many models but they list 300mm (11.8") travel for most of the big bikes and 285 (11.2") for the Sport. Were there different versions of this Magnum fork, or are they all 300mm? The Sport has 'only' 245mm rear travel so they may have modified the fork to match.

And lastly, when all of the smoke settled, which conversions have really worked out for you? I get the feeling not everyone has been happy with the results, so which ones are definitely better than the OEM R100GS fork?

[bgoodsoil]

I've got the DR650 on mine. The stem is thicker but the OD of the races are the same so DR650 bearings and races fit perfectly into BMW stem. The stem is also almost 1/4" longer but you can get 2 thick washers to take that up. It's an easy bolt up--no machining necessary.

They're definitely much stouter than my G/S forks, not to mention the better brakes, but I don't think they'd be an improvement over the later GS forks. Price and ease-of-swappage are the big advantages of the DR forks on a G/S, probably a waste of money on the GS.

[SOLO LOBO]

My local suspension GURU says that the Marzocchi Magnum forks have a real fault, they do not have internal bushings and the legs wear directly on the sliders and typically toast them on dirt bike quickly... big bikes perhaps must faster.

You can have the internals of the sliders coated, but it is expensive.

Additionally the rebound and comp adjusters are made such that they don't have any impact until the middle (?) of the stroke because they are at the top of the fork legs...

I hear the WP "Extreme" 50mm forks off of 99-2000 KTM's are the best conventional forks... and Boxer Toko makes triples that are "plug-n-play"...

[AntonLargiader]

Originally Posted by SOLO LOBO

My local suspension GURU says that the Marzocchi Magnum forks have a real fault, they do not have internal bushings and the legs wear directly on the sliders..

That would be kind of surprising, and not borne out by the repair manual which seems to show slider bushings just like the stock forks have:

http://johnandgina.smugmug.com/galle...68_UWDzq-X2-LB

[SOLO LOBO]

Originally Posted by AntonLargiader

That would be kind of surprising, and not borne out by the repair manual which seems to show slider bushings just like the stock forks have:

http://johnandgina.smugmug.com/galle...68_UWDzq-X2-LB

That would be a good thing... I have a set of marzocchi Magnum 45mm's with the KTM triples in my garage... you can wiggle the bottoms of the sliders around on the fork legs.. if it's only bushings that would be good.

Well good for some one else I a am not going to uses these and should just sell them..

Anyone want a set of Marz magnum 45's with the KTM triples for $99?

[AntonLargiader]

The manual only covered the 50, but if those 45s are at all modern I would sure think that they have bushings. Should be easy enough to pull them apart and see.

[Phreaky Phil]

I picked this lot up on the weekend. DRZ 400 front end. 49mm forks. Now to figure out the clamps. Somewhere in ADV rider there is a thread with a GS with these forks fitted. I think it had twin discs too.

[SOLO LOBO]

Just eyeballing things, it seems like the HPN/Acerbis G/S tank is shaped to allow for triples that have less offset. You will still give up steering lock going away from the BMW triples that are 36mm (or 38mm?) to 20mm or whatever, but may not hit the tank.

[Phreaky Phil]

Originally Posted by SOLO LOBO

Just eyeballing things, it seems like the HPN/Acerbis G/S tank is shaped to allow for triples that have less offset. You will still give up steering lock going away from the BMW triples that are 36mm (or 38mm?) to 20mm or whatever, but may not hit the tank.

I am concerned about having less steering lock, although I think the GS has extremely good steering lock. Quite a few of my mates have KTM 990's and they have a lot less steering lock. I suppose you get used to it. I might make up a gadget to measure amount of steering lock available and so long as I had as much or more than a KTM 990 it will be OK. I may be able to get a different tank for a similar or less price than a new set of clamps. If I had another GS tank I would consider modifying it to get clearance. I'm not sure of the effect on handling/ steering with less offset. Less offset will increase trail and should be more stable ??

[nick_rhinocycles]

I like more lock in general, but I don't miss it at all while I'm riding. You seem to notice it when moving the bike around the garage, but when moving you really don't move the bars that much.

If you want more room, you can move the tank back (If I remember correctly) Of couse the seat will have to be moved back or trimmed to fit.

This is call shipwrights disease, btw. Once you get the forks on there, you won't mind the lock.
--Nick

Originally Posted by Phreaky Phil

I am concerned about having less steering lock, although I think the GS has extremely good steering lock. Quite a few of my mates have KTM 990's and they have a lot less steering lock. I suppose you get used to it. I might make up a gadget to measure amount of steering lock available and so long as I had as much or more than a KTM 990 it will be OK. I may be able to get a different tank for a similar or less price than a new set of clamps. If I had another GS tank I would consider modifying it to get clearance. I'm not sure of the effect on handling/ steering with less offset. Less offset will increase trail and should be more stable ??

[advNZer?]

Originally Posted by Phreaky Phil

I picked this lot up on the weekend. DRZ 400 front end. 49mm forks. Now to figure out the clamps. Somewhere in ADV rider there is a thread with a GS with these forks fitted. I think it had twin discs too.

didnt you already have a ktm fork?Do you think a set of Yamaha yz 250 forks would work?

[Pigford]

I think this thread is arse-about-face - coz you should keep the Beema forks, and attached a decent bike to them

[2ndlaw]

Originally Posted by AntonLargiader

The manual only covered the 50, but if those 45s are at all modern I would sure think that they have bushings. Should be easy enough to pull them apart and see.

I know for sure the older M1's have bushings. That being said, I found wear in my ancient M1's sliders when I rebuilt them. I had to figure out proper shimming with brass shim stock to get minimal stiction with no play. So, there might be truth in the Magnum's having slider wear.

I have a nice WP extreme. One of these years I should order the Boxer Toko triples and get the thing spring correctly.

[tdrrally]

any updates?

old thread bump