Vintage BMW Motorcycle Owners

A few weeks ago I was riding, and I hit a slight bump. It sounded like a piece of metal flew out of the front end. I quickly pulled over, and couldn't find a thing. It was a clear road, so I don't think anything fell out. But that was the beginning of the troubles. A few weeks later I hit a sizeable bump, and then it sounded like there were pots and pans banging in the forks. Now every time I hit the slightest bump, there's a loud banging sound inside. Initially I thought a brake caliper had fallen off, and was dangling on the road, because it was so loud! I don't see any trouble on the outside, so it's all inside the forks.
So....I assume my 37 year old forks are shot? What do I do from here? Is this something I can manage on my own? I'm reasonably handy. Can they be repaired, or do I need to find a used set from eBay? Knowing myself, this will probably be a slow project. I have to motivate myself to start tearing the forks off the bike.

Strange. Might want to first just change the fluids and see if there's anything unusual in the oil. It's been a while since I was inside the forks, but you might want to get to a point where you can take off the top caps so the springs are free. Then with the bike supported, lift the forks together with the axle between them. Do they slide easily? You could also do a little more disassembly and try the same thing with each fork. I'm sure there are better ideas!!

I have hit a few pot holes in my time and ended up with strange noises. Along with the forks and such parts of the steering gear I would suggest you check the four main fairing mounts. In my long time as an owner of an RT bike, I have had bolts loosen and the fairing pop out of the bracket, I have also unfortunately had the threaded inserts in the fairing itself pull out causing the fairing to pop out of the mounting brackets. LOL, the bad news is they are a bit of a big pain to see as far as the top two and as for the bottom two, to get a wrench on.

Riding makes the sound hard to determine source of origin. Good luck, St.

Springs can break too, and if one bit winds into another you can get loose pieces, which might cause a noise.

It's not something loose in the storage pockets?

Charlie.

So other area to look at would be the fender area and mounting. Any kind of brace where the bolts came loose.

I am NOT saying the problem is internal to the fork legs but I can't imagine a bump would break anything unless it was one heck of a bump.

Did you have the forks apart at anytime recently, if so, recheck your work. Is this a bike you have owned and know the history of or is it a second hand bike? Previous owners are sometimes known to do incorrect things while working on the bikes. So the PO, could have assembled something wrong and it chose you to come apart on or break.

Kurt has a good idea as to what to start with if you think the problem is internal. Look on the net, there very well may be a video of how to rebuild the front end of your bike online. Right now, Brook Reams is rebuilding an ST and I am not certain but perhaps, the front end may be similar to yours. Brook always tends to make first class videos of how to put things back together correctly.

Where are you located? St.

Check the springs first. That's the most likely cause of the noise. They are easy to get to. Take the big bolts at the top end of the forks off. They should pop up about 2 inches. Make sure they are in one piece. If broken you may have to fish pieces out. Replacement springs are available from Max and I'm sure other sites.

Craig

Surprised that NO ONE has mentioned the RUBBER BUMPERS, located on the bottom of the fork sliders, that dissolve.
Broken springs, amongst the other suggestions, are spot on.

The rubber bumper was discontinued for the 1981 model year. Also if his year is correct, the 85 R80 should be a Monolever bike with the later 38 mm forks.

Take it apart and look!