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Fork Question...Missing Part?

markaz

New member
Bike is 83 R100RS, 47k miles. I removed the fork sliders to replace the leaking seals. The oil (what there was of it) was really filthy and lots of crud in the bottom of the sliders. I took the forks apart and cleaned everything and am now putting it back together. I'm a bit confused, tho, because I have a spring that does not show in the fiche and I don't have a part that is in the fiche (31422301015 - Support for damper rod). I'm told there should be a bumper in there but that it often disintegrates over time. Is that what the missing part is...perhaps that was the source of the crud? Or does that spring replace the bumper? Or ???

Here are a couple pictures showing the spring:

http://i1125.photobucket.com/albums/l598/markmonn/BMW Pix/IMG_1449.jpg

http://i1125.photobucket.com/albums/l598/markmonn/BMW Pix/IMG_1450.jpg

Of course, the bolt in the end is the one that holds the slider on. And the washer would be inside the slider. I just screwed it together for illustrative purposes.

Thanks... Mark

[Also posted to Airheads mailing list]
 
bumpers at the bottom

The bumpers usually sit at the bottom of shock components. Take a look at Max BMW parts fiche for a reference, usually right on and helpful. Yes, the bumpers decompose over time and turn to liquid goo. They must be replaced. The spring thing I am not sure of as my newest bike is a 1977. I almost always replace the bottom bumpers when I get a new bike, then, just the oil for the first couple of years. But I alwyays inspect them for condition. SOrry can't help on balance of post.
Regards,
Kurt
 
Thanks for the replies, guys. The consensus seems to be that the springs are indeed an aftermarket anti-dive mod and that I'm missing the 'Support for damper pipe', #17 in the fiche. Max's parts guy (Drew) says they have to be ordered from Germany. Looks like it'll be a while before I get it back on the road. And the weather is really nice here now. Oh well...the joys of old motorcycles...

I'm tempted to buy that kit off eBay, at least in the meantime...
 
The springs over the damping rods are old Luftmiester anti dive springs. After 1980 BMW did not put a bumper in the bottom of the fork. By new factory BMW fork springs if your bike has over 50k miles. Do not buy the Progressive brand springs. While your at it throw away the anti dive springs. With the right fork oil you will be very happy how the bike rides.
 
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