I've just found that the two are different inside.

The bike is a '92 K100RS 16v with just over 200,000kms on it. I've just changed the rear shock and have Racetech springs arriving soon (I prefer the correct single-rate rather than progressive which are often too soft).

Popping the caps off(16v) reveals direct access to the fork spring.  On the 1100 forks there is a cartridge instead.  The specs also say different amounts of oil for each type (slightly more for the 1100)

Is either of these forks substantially better than the other or are they much of a muchness?  The 1100 forks have done around 70,000kms

Al

sorry cant say al ...but do have some good thoughts about the k1100 types ...do a much better job from a quick ride on halos bike down at neranderra

in any case the less travelled forks should be much better tolerances ...(and probably still work properly )   although they have a different fit up for the calipers with those bigger discs et all
just some thoughts if it helps

Same disks etc (16v not 8v), same 135mm travel, different internals.

Al

BMW 'upgraded' the 16V forks on all models (K1, K100-16V, K100RS & LT) at the 8th month of 1991 production. So perhaps your '92 16V has the earlier design - leftovers. Same calliper spacing, etc., but much different internals.

My project has the earlier design from a late 1990 model.

yes missed it al ....and I was looking straight at it ....doh !

Al,

if you had asked me prior to Tottenham I could have given you a set of Racetech springs for the 16V forks (they're gone now).
The cartridge forks are rebound in one leg and compression in the other.
The cartridges themselves are fairly crappy in design.
I ended up replacing the stock cartridges (very small shim stack, not readily rebuildable) with ones from a Kawasaki 250/4 (compression and rebound in both legs), but it's not a bolt in swap (machining involved).
You will need to apply a die grinder to the inside of the springs to slightly enlarge the hole diameter so they sit properly on the collet.
The fork oil quantity is the same if the forks have been fully drained (which I recommend).
It is only different if draining from the fork lower drain holes.
The drain screws on the 16V forks are notorious for stripping (both of my legs have helicoils in them).
Racetech recommend 15w oil with their springs, which I found too thick (which also depends on the brand of fork oil).
See http://www.k11og.org/tech/k11tech_springs_install.shtml
Have you checked the condition of the bushes in the lower fork legs.
They are prone to wearing (I've replaced mine twice in 180,000km).

cheers,

Andrew

Thanks Andrew, I'd already ordered racetecks for the 100-16v anyway. I popped the forceps off of the 1100 forks to rob the o-ring from the caps. That's when I noticed the difference. They already feel better now that the o rings are not leaking air through allowing some compression.

This topic is about right for my question, so I won't start new thread for it.

My K100 8v from 1986 leaks oil from front forks. Renewing the seals does not help. Also front brakes are not that good anymore. So I have a plan to change whole front of the bike if I find the parts somewhere.

So the question is: Does 16v front forks fit on 8v bike so that I would not have to change anything else except the forks (and of course all brakeparts starting from handles). Do I need 16v Rim too?

You will need a complete front end including the triple clamps and throttle grip and cable, wheel, brakes including the master cylinder.
The forks are slightly larger in diameter and a bit further apart.

You'll also shorten the wheelbase considerably leading to quicker turn-in and, some say, instability due to the K100-16V/K11 Marzocchi fork's 'tighter' angle, if you retain the Monolever as compared to the Paralever which is longer by 50mm, which partially compensates.

Using a complete front end should get you the 20mm master cylinder for the four pot Brembos and you'll need a K11 throttle cable with slight mods required at the TB end - go to a set of 35mm K11 TBs at that stage. The K100 switchgear attaches as stock to the K11 'perches'.

It's doable, and yes, you'll need a wheel, 17" with 305mm floating discs, and the two-piece mudguard.

Thanks for the info. I think I will just add oil to forks when they stop leaking...

Tenox wrote:Thanks for the info. I think I will just add oil to forks when they stop leaking...

Just like you I thought it looked like a great way to go, but it's surprisingly involved. I fitted gaiters to my forks instead..