rear shocks on '78 R100 bottomed out...

[benny802]

Hi, new member here seeking info about my 1978 R100. I don't know these bikes very well yet... but mine has rear suspension that seems to be bottomed out, or something like that. the shocks are sagged down low, and they don't give at all right now. it's like riding a hardtail bike. anyone ever experienced this? are the shocks fixable or do I need new ones? and if I need new ones, anyone have any for sale??
thanks in advance for any information about these great machines.
Ben

[gertiektn]

benny... sounds like an odd situation,if the shocks are bottomed... I am assuming the springs are full compressed, broken or you have a set of air (numatics)with a big rubber boot that have gone flat. It might help to post a pic of your situation..

The stock air head has 13.5" eye to eye shocks with open springs..(some of the early ones have a aluminum cover on the upper part of the spring) There are always some stock ones for sale on Ebay. Just put in "BMW R Shocks" and you will get a list.
Most of the used shocks are exactly that... used, but can be had for a bargain to get you by, but..... be warned that they may be totally worn out and have no dampening ability. No dampening means bad handling, so be careful. A functional set could get you by until you get to better know the bike..

New units are available from the major manufacturers and expect to pay... $400 and up for new sets.
Post a picture..
Good luck on this..

Jim, Ketchikan

[SteveD]

Yep, it'd be good to know the brand of the shock. Some can be and do get rebuilt, like the Koni.

Others aren't. Generally, most ditch the oem shocks when sagged and replace them. If they're the oem set, then I'd expect them to be well passed their functional usefulness.

Welcome aboard. Where you from, and how about a picture of the bike and shocks?

[R90Steve]

I have seen a couple of causes of what you desribe. A bent rod or a displaced internal seal will cause the shock to bind and not respond to the rebound force of the spring. If you take the shocks off or at least undo them at their tops,with the back wheel off the deck, it will be easy to tell if you need two or just one.

[Frog]

Also, check to make sure that the swing arm pivots are working properly. I recently worked on a honda....who's owner wanted me to install a new rear shock. He thought his old one was bad. As it turned out, the swingarm needle bearing (we have tapered) had deteriorated, broken and was bound up. The swingarm was no longer moving properly. His shock was fine.

[Steve78RS]

Ben

I own a 78 R100RS and yes I've replaced the original shocks for the reasons you describe. After thirty years and trying to cope with my 105 kg body mass, they were not up to the job. I've replaced with a new set of Ikons. I think the oem units can be rebuilt?

http://www.ikonsuspension.com/

Steve from Dubbo

[teo]

Hi Benny,
The Boge OEM shocks on my R65LS pumped down exactly as you described yours. Boges are not rebuildable. I cut them open to see why and how they could bind. The plastic or nylon washer/separator inside had disintegrated, turning into a cornmeal-looking muck. That would block the valving holes as the shocked worked and the shock would work down til it was locked. Toss'em.

I don't recommend getting original OEM used R-bike shocks off e-bay. They will most likely be trashed and were never very good. They don't last long either.

You can find a good set of used (and rebuildable) Konis on e-bay for $100 or less and rebuild them for $25 to $50. Parts can be had from Craig Vechorek or from IKON in Australia. I do it all the time - I love rescuing Konis . Search this forum for a set of fotos and instructions on how to rebuild them.

New Ikons are reasonable and perfectly suited for your bike. IKON bought the tools and license from Koni for bike shocks. I think their quality is the same or better than Koni. The will cost about $400 and are available from most of the BMW dealers (Max, Bob's, Vechoreck, IKON, etc).

Either Ikon or Koni for your bike are model number 7610-1298. The 1298 is the number indicating it's for the R75/80/90/100 bikes. They are 13.5" center eye to center eye and are ajustable for damping and ride height. There is an older Koni 76P-1298 that is not adjustable at the upper eye. They are good but harder to rebuild.

I have a set of Wilber classics on my R65 but keep a set of konis in reserve. I have the 1298s on my R-75.

Good luck,
Teo

[ME 109]

Benny? Benny, you there?
Hello operater, Operater? Bah.
Click......

[benny802]

here I am! I've been busy. thanks for all the replies. I have a few photos, I'll see if I can figure out how to post them!

so when the bike is on the centerstand, the shocks "look" normal, and there is about 13.25" from mounting bolt to mounting bolt. when i put it on the sidestand however, they "look" compressed, and don't give when I sit on the seat. on the side stand, the bolt-bolt measurement is about 11". so it's not like the shocks are bound up, it seems that they are just shot.

okay, i'm trying to use photobucket to get photos on here but I keep having errors I don't understand. I'm not very techy with this stuff. what is a good way to get pictures here??

Thanks!

[ME 109]

Gidday Benny, photobucket is good for posting photos.
I have to go to work now but someone will be along soon to explain how to do it.