F800gs - Almost perfect except for poor suspension.

[Lucky Jack]

thanks that was a very helpful reply

[The Griz]

Originally Posted by Lucky Jack

perhaps due to lack perfect suspension settings, last weekend, when my 800 was temporarily upside down post a trail crash I noticed some blue liquid on the ride side of the bike near and around the right side fairing.

Would this be the antifreeze ?

Checked the coolant tank. And its lid and it appeared to be fine. Is there an over flow resevoir that could have released liquid once it was upside down?
thanks for any advice

I'm assuming, yes, this would be antifreeze. Due to the fact that the coolant reservoir and coolant lines to and from the motor and radiator are on the right side. As well as the fact that the stock coolant BMW puts in is blue in color! Check the two fat hoses that come from the radiator and connect to the engine on the right side. They may have worked loose. There's not much else that would leak. Even upside down. The forks and rear shock are sealed. The gas tank is sealed. The battery is sealed AGM Maintenance-free. Engine oil is sealed. Has to be a coolant leak.

[Lucky Jack]

Originally Posted by The Griz

I'm assuming, yes, this would be antifreeze. Due to the fact that the coolant reservoir and coolant lines to and from the motor and radiator are on the right side. As well as the fact that the stock coolant BMW puts in is blue in color! Check the two fat hoses that come from the radiator and connect to the engine on the right side. They've been known to come off in rough riding conditions. There's not much else that would leak. Even upside down. The forks and rear shock are sealed. The gas tank is sealed. The battery is sealed AGM Maintenance-free. Engine oil is sealed. Has to be a coolant leak.

cool, thanks, Griz

[sgopher185]

Originally Posted by trailtrick

No cartdiges on stock ,you need the get guts froma 650 x or from marzochi and re work the complete forks ,and you have 1 for rebound and 1 for compresion went done .54 o .56 fork springs ,10 mm longer so you ditch the spacer's .,i take pictures for the 2 i have here went the springs and guts show up next week .,i also match theme with ohlins shock

This seems to be what I was thinking of doing to my f800gs when I have the funds.

Just to clarify do you mean each fork has rebound and compression adjustment or is one fork set up for rebound and one for compression?
If these are set up as the latter (one for rebound, one for compression), is it possible to set up both for rebound and compression like the te610 marzocchi forks (06 and 07 I think)?

Definitely looking forward to the pictures.

[lawe]

Has anyone tried the emulators from Race Tech? They have an emulator to put into damper rod forks which shall make it behave like a catridge fork. The have emulators for the F650 single but not for the F8 accoring to the web site (i have emailed them though)

But do these emulators really work?

EDIT: Here's a good link about the emulators: http://www.sportrider.com/tech/146_9502_tech/index.html

/Lars

[huckleberry]

Originally Posted by lawe

Has anyone tried the emulators from Race Tech? They have an emulator to put into damper rod forks which shall make it behave like a catridge fork. The have emulators for the F650 single but not for the F8 accoring to the web site (i have emailed them though)

But do these emulators really work?

EDIT: Here's a good link about the emulators: http://www.sportrider.com/tech/146_9502_tech/index.html

/Lars

they haven't made them yet they need a bike so they can make them soooooowe need someone to drop off their 650 and someone to drop off their 800 so they can make them!!!!!

[lawe]

Anyone with an F8 in the neighbourhood of Race Tech?

I'm a bit to far away i'm afraid...

[itsatdm]

I have been preaching to reduce oil viscosity as a cure for the BMW fork issues on the 800, hard to admit, but I was wrong.
After attempting to get some information about these forks from BMW, Marzocchi and Rev Tech without much success I found thes people: http://www.aftershocks-suspension.com/pages/contact.htm
Not only have they taken these forks apart, they actually fix them. No I have not utilyzed their services yet, but they did pass on some valuable information.
As Trailtrick discovered, these are indeed damping rod forks. They are set up for 160# riders and work fairly well for those riders, if the rider weighs more than 180# you start experiencing the problems noted on this thread.
Contrary to what I thought, the holes in the damper unit are not too small they are too big and located in the wrong place, right at the bottom of the damping unit. What we are experiencing is a hydraulic spike, where too much oil is coming into the unit with no place to go. Their cure is to reduce the size of these holes and place others further up the unit, which again sounds like what Trailtrick is doing. In my case they suggested heavier oil to slow the flow into the unit and elongate the spike, thus feel smoother.
So I tried the 10 wt. oil that Hyperpro sent along with my springs and guess what, it works.
Further tidbits, included that the first step in getting a better ride out of the 800 is to deal with the rear shock. I don't understand all of it, but Bmw built these bikes to mimic the ride of the larger GS and they seem to think that improving the rear is key.
Apparently I did not do everything wrong, these bikes do not like preload and are very sensitive to using it to correct sag issues. I managed to do that, with the changing out of both springs and the use of coil spacers on the front. That is probably where my improvement came from.
They also do not seem to think that cartridge emulators will solve the problem alone and recommend modifying the the damping tubes with or without them although they will give you more flexability.
My current set up is Hyperpro front and rear, coil spacers used on the front, 10 weight oil, no preload on the rear, max rebound. The brand of spring is not that important, the key is to arrive at the proper sag.


Its the internet read then verify

[Bayner]

Thanks for the update Itsatdm. I haven't ridden mine offroad yet as the snowline is still at the valley bottom, but I suspect I will want to improve the suspension preformance when I do as I'm coming from a thumper background. Your info and experiences are going to prove valuable no doubt.

[Eurastus]

Originally Posted by itsatdm

My current set up is...no preload on the rear, max rebound.

OK, I understand no preload. That's simple enough. But do you mean that you have the damping screw tightened all the way clockwise, giving maximum damping (hard), or loosened all the way counterclockwise giving maximum rebound (soft)?

The manual seems to be contradictory.

On page 52 and 53 it states that the recommended settings for a 187 lbs rider with gear (pretty much my weight) is for no preload; it states to turn the preload counterclockwise all the way. Damping is recommended to be set almost at maximum; it states to turn the damping all the way in clockwise to make it hard as possible, then back off 1 1/2 "clicks" (I feel no clicks in the damping screw, by the way, though I do feel "clicks" when I loosen the preload adjustment). Perhaps they mean 1 1/2 turns?

Yet another statement on page 52 is that "...a reduction in spring preload requires softer damping". This seems to be the opposite of the recommended settings.

Am I not understanding or is there indeed a contradiction here?

As you suggested, I am reading...then verifying.

[itsatdm]

Originally Posted by Eurastus

OK, I understand no preload. That's simple enough. But do you mean that you have the damping screw tightened all the way clockwise, giving maximum damping (hard), or loosened all the way counterclockwise giving maximum rebound (soft)?

The manual on page 52 and 53 seems to be contradictory in that the recommended settings for 187 lbs rider is no preload (it states to turn the preload counterclockwise all the way) and very high damping (it states to turn the damping all the way in clockwise to make it hard as possible, then back off 1 1/2 "clicks" (I feel no clicks, by the way)).

Yet another statement on page 52 is that "...a reduction in spring preload requires softer damping".

Am I not understanding or is there indeed a contradiction here?

As you suggested, I am reading...then verifying.

Clockwise= more damping. You should only use enough to get the desired effect. Generally, the stiffer the spring, the more rebound damping is required . I am near max on mine (1/2turn out from full hard) because of the stiff spring I am running on the rear, the stocker should not require as much.
Mine doesn't click either. The great unknown is just how effective the damper unit is in the first place, though I could certainly feel the difference.

[Eurastus]

Originally Posted by itsatdm

Clockwise= more damping. You should only use enough to get the desired effect.

Do you know if the damping on the stock setup is compression, rebound, or both?

What do you judge is "the desired effect"?

[tmex]

Originally Posted by itsatdm

I have been preaching to reduce oil viscosity as a cure for the BMW fork issues on the 800, hard to admit, but I was wrong.
After attempting to get some information about these forks from BMW, Marzocchi and Rev Tech without much success I found thes people: http://www.aftershocks-suspension.com/pages/contact.htm
Not only have they taken these forks apart, they actually fix them. No I have not utilyzed their services yet, but they did pass on some valuable information.
As Trailtrick discovered, these are indeed damping rod forks. They are set up for 160# riders and work fairly well for those riders, if the rider weighs more than 180# you start experiencing the problems noted on this thread.
Contrary to what I thought, the holes in the damper unit are not too small they are too big and located in the wrong place, right at the bottom of the damping unit. What we are experiencing is a hydraulic spike, where too much oil is coming into the unit with no place to go. Their cure is to reduce the size of these holes and place others further up the unit, which again sounds like what Trailtrick is doing. In my case they suggested heavier oil to slow the flow into the unit and elongate the spike, thus feel smoother.
So I tried the 10 wt. oil that Hyperpro sent along with my springs and guess what, it works.
Further tidbits, included that the first step in getting a better ride out of the 800 is to deal with the rear shock. I don't understand all of it, but Bmw built these bikes to mimic the ride of the larger GS and they seem to think that improving the rear is key.
Apparently I did not do everything wrong, these bikes do not like preload and are very sensitive to using it to correct sag issues. I managed to do that, with the changing out of both springs and the use of coil spacers on the front. That is probably where my improvement came from.
They also do not seem to think that cartridge emulators will solve the problem alone and recommend modifying the the damping tubes with or without them although they will give you more flexability.
My current set up is Hyperpro front and rear, coil spacers used on the front, 10 weight oil, no preload on the rear, max rebound. The brand of spring is not that important, the key is to arrive at the proper sag.


Its the internet read then verify

I've used Aftershocks for some KTM suspension work when they were located in Palo Alto. Phil Douglas is a good guy and knows what he is doing, but like all suspension shops you never know exactly when you will get something back and what exactly you will get back. Phil's shop does not exactly inspire confidence - looks like an explosion in a fork factory. I had good luck with them.

Javier has a great reputation as well, and when I get past this lazy period I am in I am going to let him breathe on my HP2 forks. The F800GS seems to just keep getting better and better the more I ride it. I am either getting used to it or it really is breaking in - maybe a combination of effects at work here.

[The Griz]

Originally Posted by tmex

The F800GS seems to just keep getting better and better the more I ride it. I am either getting used to it or it really is breaking in - maybe a combination of effects at work here.

Go to hear, tmex!

[itsatdm]

Originally Posted by Eurastus

Do you know if the damping on the stock setup is compression, rebound, or both?

What do you judge is "the desired effect"?

It controls rebound only. I interpret it to mean, hard enough the rear doesn't spring up too quickly or bounce more than once, yet hard enough that it doesn't rebound so slowly that the shock packs. If it is any help, I tried all kinds of setting with the stock spring at 1&1/2 turns out.