R100GS vs GS Basic (NOT G/S) fork differences?

[sidkn33]

Hello Airheads.

Does anyone know what the difference is between forks, shown below?

Both are Airhead GS (not G/S!), but one set has black lowers the other has white = possibly from a GS Basic?
The original forks on my bike had the black lowers and black caps with hex inner, the other set with the white lowers has a very different. silver alloy top with a threaded part proud of the top, and a large and smaller, hex inners - I got these white ones on eBay last year, unknown origin, and fitted them recently - the ride feels better (sophisticated reaction to bumps and less dive under braking) and I'm wondering if these have had a modification that the alloy caps indicate or these are GS Basic forks and different from the factory.

 

[Vulpine2]

Your two detail pictures show the early (88-90) and late (91 on) GS forks. The latter as presumably fitted to the Basic models. To my knowledge there are no internal differences - all part numbers are the same, just different caps (and yokes). No idea why BMW changed the set up. Your improved ride could well be down to aftermarket springs/racetech valves/different fork oil mix. White lowers look good

 

[mikeyboy]

Your two detail pictures show the early (88-90) and late (91 on) GS forks. The latter as presumably fitted to the Basic models. To my knowledge there are no internal differences - all part numbers are the same, just different caps (and yokes). No idea why BMW changed the set up. Your improved ride could well be down to aftermarket springs/racetech valves/different fork oil mix. White lowers look good

That about sums it up,only thing I could add would be the later set up could allow more stiffness to the upper bridge yoke with more torque on the fixings?
I’ll add,the threaded fixings on the BASIC,yoke are for the additional instrument pods

 

[sidkn33]

Your two detail pictures show the early (88-90) and late (91 on) GS forks. The latter as presumably fitted to the Basic models. To my knowledge there are no internal differences - all part numbers are the same, just different caps (and yokes). No idea why BMW changed the set up. Your improved ride could well be down to aftermarket springs/racetech valves/different fork oil mix. White lowers look good

Thanks, but do you mean that the black topped forks, 1st photo, are 91 on and the ones I have fitted, 2nd photo, with white lowers and silver alloy tops are 88-90?

 

[sidkn33]

That about sums it up,only thing I could add would be the later set up could allow more stiffness to the upper bridge yoke with more torque on the fixings?
I’ll add,the threaded fixings on the BASIC,yoke are for the additional instrument pods

Interesting, re threaded fixings and instrument pods. I have a set of those that I had fitted to my ST, but the ST and G/S don't have proud threaded tops. So Basic pods were different to G/S ST ?

 

[mikeyboy]

Interesting, re threaded fixings and instrument pods. I have a set of those that I had fitted to my ST, but the ST and G/S don't have proud threaded tops. So Basic pods were different to G/S ST ?

G/s and st forks ,the indicator/pod mounts were fixed under the top mounts.
On the basic they were fixed on top of the threaded bit with an additional nut

 

[sidkn33]

Thanks, but do you mean that the black topped forks, 1st photo, are 91 on and the ones I have fitted, 2nd photo, with white lowers and silver alloy tops are 88-90?

The reason I'm checking is that the white forks with the silver alloy tops, seemingly from a Basic which was produced in 1996 I think, replaced the black topped and bottomed forks

Thanks, but do you mean that the black topped forks, 1st photo, are 91 on and the ones I have fitted, 2nd photo, with white lowers and silver alloy tops are 88-90?

Just to clarify, I previously owned a UK 1993 R100GS and my current R80GSPD is 1992 - both had these forks with black lowers.

 

[Vulpine2]

Threaded alloy caps are the 88-90 bikes, which use the early yokes. Black caps are as fitted to the later bikes with frame mounted fairing together with the later yokes. Looking at OEM it appears that the only exception to this is the Basic - which has the early caps/later yokes combo. Initially struck me as odd but makes sense given that it’s a later bike - but one without that fairing/scaffolding for mounting the indicators. Top anoraking or what? Every day’s a school day.
Dunno about the ST and g/s, they’re probably a whole different ballgame…

 

[sidkn33]

Threaded alloy caps are the 88-90 bikes, which use the early yokes. Black caps are as fitted to the later bikes with frame mounted fairing together with the later yokes. Looking at OEM it appears that the only exception to this is the Basic - which has the early caps/later yokes combo. Initially struck me as odd but makes sense given that it’s a later bike - but one without that fairing/scaffolding for mounting the indicators. Top anoraking or what? Every day’s a school day.
Dunno about the ST and g/s, they’re probably a whole different ballgame…

The ST and G/S are indeed a whole different ballgame - I just fitted a set of '92 GS forks to my '83 ST for that reason.

 

[Bubb]

Sidkn33
Me too…… my st is more g/s bitsa now than ST.
Post pics of your ST please.
Mine below….

 

[sidkn33]

Sidkn33
Me too…… my st is more g/s bitsa now than ST.
Post pics of your ST please.
Mine below….

I think I admired your machine when I saw it for sale a year or so ago?!
Very nice.

This is mine, originally with the ST wheel fitted to the GS forks, using a custom axle
(thanks to forum member ScooterPaul) and with a GS1150 4 pot caliper and the OEM ST brake rotor which is too small.

The second pic is curren, now with a custom made 285mm rotor to fit the franken-fork-brake arrangement.
It handles very nicely with the 19" front and has much improved braking, as you'd expect.

 

[Bubb]

Sid

Your St looks great…..
Yes, I did have my ST up for sale, but decided to keep her instead. ….and glad I decided to keep her.

 

[sidkn33]

Thanks, appreciate the feedback.
You made a good decision!