So I'm sitting at Bob's BMW again. After riding Josh's bike, the last time we rode together, I've realized that somewhere along the way my bike has developed a serious handling issue.

At speed it's just squirrelly. It refuses to track a straight line and just doesn't feel planted in corners. This has been getting worse over the last 20,000 miles or so.

On the '92 K100RS, the steering head bearings are a 25,000 mile replacement item. This set has 45,000 on it so I'm having them replaced. It was another job I didn't feel like tackling myself.

There doesn't seem to be any notching, but I remember at 25,000 miles when I had them done when the tech looked at them they were worse than one would have expected.

It's still possible that it's the forks and or rear shock but I figure take care of known maintenance items first. I'm hoping to upgrade the shock and have the forks done at some point over the winter.

I'm beginning to consider taking the R1100S to Deal's Gap.

Steering head bearings have been replaced and the handling of the bike is significantly improved but not back to completely normal. The tech, Steve, said the bearings were loose and that the grease had long since gotten old.

The bike is more stable and corners better. Most of the wobbling is gone. I'm thinking that maybe the progressive rear shock is on it's way out.

Unfortunately, with the Remus exhaust on the bike it vibrates alot more than it used to. It's not nearly as pleasant to ride. Nothing to be done for it, since the stock exhaust has such a serious design flaw.

Now that a few days have gone by the detail job Yun did on it has really started to shine. The bike looks really good.

Considering that the service interval on Ohlins is 20,000 miles, it's a good bet the your progressive shock is ready for either rebuild or replacement at this point.

Progressive's tech support number is:
714.523.8700

Of course, there's always Wilbers who as you know, will make a shock custom for any bike:



831.438.1100

Racetech doesn't list a rear shock for the K100RS 16V, but they DO list a front fork emulator kit which would make your front suspension adjustable.



This along with either rebuilding your prog rear or replacing it with an ohlins would likely make a pretty drastic improvement in the handling.

Good info. Thanks!

I know this is something you've probably considered, but what about your wheel bearings?

There is (are?) also the swingarm bearings to think about. Wheel bearings are pretty simple to change on most bikes, though I'm not sure about how the single sided swingarm and shaft drive affects the difficulty.

@SprintKS good point. I had not considered that. I'm going to have to check but I think the wheel bearings were done when I had the wheels straightened after a trip to Maine.

@Matt I was looking at the bike and it looks to me like it /might/ be possible that there could be some swingarm bearings that could loosen. Redoing the head bearings definitely made a big difference but it's not 100% right. I think I would agree with Duncan that the suspension parts, the obvious stuff, is probably shot. I've never been happy with the progressive suspension parts I put on there. Over the winter there might need to be some Wilburs suspension upgrades.

I was just looking into replacement steering head bearings for my bike and learned that there are tapered roller bearings available in addition to the OEM ball bearing sets. The roller bearing sets are reported to last pretty much forever. Like this:



You've already replaced yours, but I was wondering if that was an option for your bike.

Given how old and unpopular my bike is I would seriously doubt it but when they are due for replacement in 25K I'll see if there are any alternatives available.

In general, I've found that bearings are universal- you shouldn't have any problems finding bearings for even really old bikes. I've also seen that buying bearings from the dealer is a a good way to spend lots of extra money- you can get the exact same bearing at a bearing store for usually less than 1/4 the price.

I did not know that. Thanks, Matt!

I was looking at a schematic on the K.
it has an interesting bearing & pivot pin assembly that the swing arm moves on.

wear in these parts could/would allow side to side movement and possible tracking problems

I will have to check that out. I talked to the tech. Steve, about those bearings and examining the bike he thought they were fine, but then again he thought the steering head bearings were fine.

I find myself wondering if steering head bearings "break in". The bike is actually handling much better now and is leaning much more confidently.

I get the Ohlins rear shock installed and set up on Wednesday. We'll see what, if any, improvements that brings.

Bearings don't break in- other than perhaps sealed bearing may get a bit looser as the seal stops being tight. I think you'll only find sealed bearings on wheels. I don't think they would *ever* go from looser to tighter.

Steering head bearing are pretty sensitive to the torque on the head-set. A worn steering head bearing is pretty distinctive (particularly when very worn), as you get a distinct click under hard braking, particularly when you're not going fast (as the drag load that would cause the click is already there). If you're going to adjust the torque on the head bearings you must rememeber to loosen almost everything around the head (triple clamps, even the fender, as that has some affect on the stiffness).
  

I replaced the head bearings on my R100RS years ago when they were really worn, with a distinct click. Replaced them with new tapered roller bearings (it had tapered roller bearings when I got it) and while better, they still had a bit of a click under braking. Never was very happy with the replacement- but it could be that the (now) 40/50 year old design has been eclipsed by much better understanding of chassis dynamics.

Something that can be harder to diagnose (and pretty common on an older bike that has been ridden on ... unsmooth roads is slightly bent fork tubes, as they can cause a bit of stickiness in the suspension travel.

Talking to Steve over at Bob's had left me with the impression that doing the head bearings on these older bikes "correctly" is kind of a black art. You get a feel for it after having done several. I had considered doing the job myself, but decided to ask them to do it.

The replacement interval for the bearings on my bike is 25K. I may try to do that job myself next time.

I've considered the fork tube thing as well but wouldn't know how to go about determining if they are bent. I'll ask them about that on Wednesday.

Those older bikes also have small fork tubes for the size of the bike.

I guess you can't do a front end swap, like SV riders do by putting on a GSXR front end.

Yea, from what I know there really isn't any option to replacing the front end.

The tubes are pretty small for the size of the bike but I still have the sense there's something wrong with the handling. It may be tweaked tubes as Matt suggested. I also think the Progressive Springs I have in there are not correct and that maybe going with a different brand of spring more correctly tuned to this bike might make a big difference.

Checking fork tubes is pretty easy if you have them disassembled and a very flat surface- just roll them on the flat surface and see if any gaps open up. You can also do the "look down the tube" thing. They don't have to be perfectly straight- there probably is a spec in the manual- something like how big a feeler you can slide in when you do the rolling on a flat surface.

@Matt Good point. I should have realized that.

Have you checked the bushings in the telelever arm?

any abnormal movement from worn bushings/bearings (parts) in either the rear or front suspension will cause strange handling.

You mean the paralever. Telelever is their newer front suspension.

Yea, while I was at Bob's the last time the tech checked the other possible wear points and said he thought that was all ok.

My feeling is the problem, whatever it is, is in the front end. It might that the geometry of the bike is off. Too high in the front, too low in the fear. It might be stiction. It might be something is bent. I'm not sure.

for some reason I was thinking it was like the "S".