R65GS Front end

[Vincent]

Hi,
During the rebuilt of my R65 GS, I've replaced the original springs by progressive ones from motorworks and the bike's front end has felt quite low and hard since. I've recently replaced the oil from 10w to 7.5w and it made it a much nicer and more pleasurable ride. I'm not sure how high the forks should be and how much drop should I get...When the bike is on its stand, the forks are 82.5cm long (from bottom of the lower leg to top of stanchion).

When taking the bike (full tank) off the centre stand they drop by 4cm (forks lengt 78.5cm).

With me on the bike (I'm 75kg) they drop by another 2.2cm at 76.3cm.

Does it sound ok to you? It really feels like the front end is dipping forward but it might be having driven the super tall f650 gs Dakar for while...Would it be worth replacing the spring by something stronger like Ohlins or fitting a spacer in there? I'd like the front end to barely drop from its centre stand position (it would feel like the correct riding position) while keeping smooth suspension. The other option would be to replace the whole front end by a R100GS one but they're quite hard to source.
Any advice on this would be more than welcome
Also, I'm thinking of replacing the BMW rear suspension by something like the Hagon one. Is that a real improvement from the BMW one?
Many thanks
Cheers
Vince

 

[Beemerboff]

That is too much sag, around 50 mm total would be closer.

But I cant say if the spring is to soft, or too short, or both.

Try adding a preload spacer above the spring - from memory the spring should be compressed just to the point where it is needs a bit of effort to push down the fork top nut and catch the first thread.

Another check is to stand the bike vertical on its wheels and push down on the riders footrest - both ends should fall by the same amount - if the front drops more the springs are too soft.

 

[(RIP) Proff]

25mm/ 50mm spacers on top of the springs

I've got 35 mm in r90s and 25mm in 80g/s

 

[Padmei]

Cool bike. What front guard is that?

 

[Dazzle]

I was thinking of putting Wilber's or some other progressive springs in my R100Gs as the standard ones don't like braking and bumps at the same time
I'd be interested in a good set up for a Gs front end
I presume a 100 front end is different to a 65

 

[Benjamin M]

I was thinking of putting Wilber's or some other progressive springs in my R100Gs as the standard ones don't like braking and bumps at the same time
I'd be interested in a good set up for a Gs front end
I presume a 100 front end is different to a 65

Yep 40mm Marzocchi forks on the paralever GS, as opposed to the spindly forks adapted from a road going BMW IIRC on the monolver R80G/S & R65G/S

In case it's of use to you, there's a big thread about HPN Magnum inserts for paralever forks on advrider in their airhead section, though I am unsure as to whether or not they're still available from HPN themselves

 

[boxertricks]

I have measured my 65g/s and get the same 4cm compression figure as you. The mudguard looks the same as mine and is the normal BMW part.

 

[Vincent]

Thanks for the replies,
I think I will go for the spacers on top of the springs. Where could I find those? Seems like a DIY job can be done but I can't think of anything laying around in the garage that could do it.
I'm also a bit worried about the fitting. I remember fitting the new springs was a real struggle. Do the stanchion need to come off or can it be done from the top? If I remember well it was almost impossible to push the spring in enough to fit the ring holding the top nut in place...
Cheers
Vincent

 

[fayeslane]

Thanks for the replies,
I think I will go for the spacers on top of the springs. Where could I find those? Seems like a DIY job can be done but I can't think of anything laying around in the garage that could do it.

Coins

 

[Benjamin M]

Coins

Sounds expensive

 

[fayeslane]

Sounds expensive

I was working in Oz dollars

 

[dr nosh]

Try 'Greek' Euros.

There not worth much

 

[VAL. H.]

I'm thinking of replacing the BMW rear suspension by something like the Hagon one. Is that a real improvement from the BMW one?
Many thanks
Cheers
Vince

Hagon are the bottom of the tree where rear suspension is concerned. When new they are great. After a while they go off the boil and become worse than the one you replaced. There are much better optiins out there. Having you original one rebuilt (google Falcon Shocks) or PM KevEngland for info on the one he put on his ST. That one was very well priced iirc.


Val.

 

[Beemerboff]

HPN inserts

HPN have stopped selling the inserts, but someone on the ADV riders has commissioned around a dozen sets from elsewhere, and there might be a few spare.

Try the Old School BMW forum under, er, HPN inserts.

Maxton could probably make you something too.

The springs for the HPN kit are available from one of the German spring suppliers, and with the correct spacers would be a cheap entry point, together with a little more rebound damping and a little less compression damping. ie 15 wt and 5wt oil respectivly/

 

[davidh2008]

wow nice...but sounds expensive

 

[Dazzle]

I was just looking to freshen up the front end with new springs and oil really
I don't ride it that hard

 

[Beemerboff]

HJyperpro

Hyperpro have a good listing on BMW fork springs, including the springs for the cartridge inserts which HPN and the factory used to sell.

Apart from the different springs the main difference the (Expensive) inserts have is more rebound damping, and less compression damping.

So fitting the cartridge springs, properly preloaded, and changing the fork oil would be one way of attempting to replicate the performance of the inserts, at a lot less cost.

Don't worry about progressive springs - there is a good reason that Ohlins, Traxion Dynamics, Maxton and other suspension specialists dont use them.

You could add Rob Farmer to that list - he does have a thread which demonstrates why.

 

[Vincent]

Wouaw, loads of info here!That's great!
I think I'll start with the spacers and upgrade if it doesn't suit me.
What material should I use? Is PVC alright? I see that it is commonly done... or should I go for something a bit stronger? When refitting my forks I started with the stanchions and then fitted the springs from the top, then the plug and the ring holding it. Is that how I should go about it with the spacers?
Cheers
Vincent

 

[(RIP) Proff]

Mine are made of Aluminium, I'll post a pic in a tick

EDIT 12 mm x 26mm these are for my Smoke grey R90s i'm working on ..

 

[Mick13]

For the WP progressive springs on my 80 G/S I've had to had spacers also.
In fact I don't have really notice an improvement with progressive springs