K76C - Improving handling

[r65lsk75c]

I purchased a K75C new and have owned it since 1987. As dependable as this bike has been, it has never overwhelmed me with confidence in its handling. Please understand that I am a very conservative rider and never expected "race track" handling with this motorcycle. My best description of the problem is a squirrly feeling in the front end when cornering. About 12 years ago, I added Progressive fork springs, other than that the bike is stock (including the rear shock). The bike has about 30K miles on it. What are the most cost effective methods for improving the handling of this motorcycle. I would be satisfied if it simply felt as "secure" as my old British bikes in the corners.

All suggestions are appreciated.

Rick T
1987 K75C
1982 R65LS
1975 Norton Commando
1974 Triumph Trident

[kbasa]

I purchased a K75C new and have owned it since 1987. As dependable as this bike has been, it has never overwhelmed me with confidence in its handling. Please understand that I am a very conservative rider and never expected "race track" handling with this motorcycle. My best description of the problem is a squirrly feeling in the front end when cornering. About 12 years ago, I added Progressive fork springs, other than that the bike is stock (including the rear shock). The bike has about 30K miles on it. What are the most cost effective methods for improving the handling of this motorcycle. I would be satisfied if it simply felt as "secure" as my old British bikes in the corners.

All suggestions are appreciated.

Rick T
1987 K75C
1982 R65LS
1975 Norton Commando
1974 Triumph Trident


How about a new shock for the rear there? I had a Progressive Suspension unit on my K75C and it helped.

Adjustment was key, though, like any shock.

[wndsrfr]

Have you considered lowering it? My inseam is 30 inches and my '92 K75RTwas too topheavy for me to easily handle pushing into/out of the storage barn or dropping off the centerstand on unlevel ground. Too many right side drops (count 'em by the damage to the fairings) convinced me to do something about that.

I've just added a shorter rear shock by Progressive which dropped the rear by about 3/4 inch. The front was lowered by loosening the triple clamps and letting the tubes slide up by 3/4". The feel of the bike is quite different now, with the center of gravity somewhat more in line with the center of the wheels. Nice thing is that the footpeg to seat relationship stays the same versus getting the low seat. This keeps the comfort level high.

I haven't been through the adjustments on the new rear shock to fine tune anything yet and am looking forward to evaluating how that changes things. Any pointers that others have on lowered bikes would help....

[snowcat]

r65lsk75c
I own a 88 K75C and have improved the handling quite a bit by adding a Works spring kit and rear shock.
Also my local BMW dealer advised me to switch from a 100/90/18 to a 110/90/18 front tire for better handling.
Since I installed the suspension and tires at the same time I'm not sure how much of a difference just the change in tire size would make.
Also I have a VERY slow leak at my front wheel and not having the tires at the right pressure makes a huge difference.
good luck
snowcat

[barryg]

Kbasa's opinion of the Progressive shock is good. I think they make two standard shocks for that bike. Get the 420. It's the better value,supposedly rebuildable and it looks good to. I have run one on my 87 K100 for 7 years. The stock shock is good for about 3/4 years of normal use, then their shot. You may want to do a total service on your fork legs. It appears that it has been several years since you added the fork springs. When the bike is new every thing feels good about the bike. Over the years the bike tends to slowly wearout evan just sitting, anew shock, properly adjusted; a fresh rebuild on the front forks; and a new set of tires and I think your back in business.

[davel]

The bike has about 30K miles on it. What are the most cost effective methods for improving the handling of this motorcycle.

I had a 88K75s that handled pretty good with the stock setup, BMW gave it much better suspension then the C,T models and even the K100 series for a while. I replaced the rear at 30K miles with a KONI which was really stiff, but the bike handled great... :dance

[kbasa]

I had a 88K75s that handled pretty good with the stock setup, BMW gave it much better suspension then the C,T models and even the K100 series for a while. I replaced the rear at 30K miles with a KONI which was really stiff, but the bike handled great... :dance

You can buy a kit that has the S bike internals from BMW. You take the old fork internals out and replace them with the stuff in the kit.

Voila! Instant S bike front end.

Tina had a Koni on her K75, but I agree, it was ridiculously stiff.

[jdiaz]

I would not spend any money on aftermarket suspension until this ~20 year-old bike is freshened with new steering head bearings, a re-greased or replaced fluidbloc damper, and new swingarm bearings. Start with a good baseline before you spend any extra cabbage.

[deilenberger]

I purchased a K75C new and have owned it since 1987. As dependable as this bike has been, it has never overwhelmed me with confidence in its handling. Please understand that I am a very conservative rider and never expected "race track" handling with this motorcycle. My best description of the problem is a squirrly feeling in the front end when cornering. About 12 years ago, I added Progressive fork springs, other than that the bike is stock (including the rear shock). The bike has about 30K miles on it. What are the most cost effective methods for improving the handling of this motorcycle. I would be satisfied if it simply felt as "secure" as my old British bikes in the corners.

All suggestions are appreciated.

Rick T
1987 K75C
1982 R65LS
1975 Norton Commando
1974 Triumph Trident

Since you have an '87 C - there is a good chance it doesn't have the "Sport Forks" - you can tell by looking at them. The fork tube cap - under the black snap-on cap - may have an "S" stamped into it - if so you have sport forks. If you have a 2 piece fender with a "bridge" between the two sliders, chances are good you have the sport forks. If your original springs were two piece - a big spring and a little spring - you have the sport forks.

If not - the parts are available to convert your forks to the sport forks. Less travel than the original K forks - but much better control. I'd suggest replacing your elderly Progressive springs with a set of Works Performance dual-rate springs. I found these to be more "secure" feeling.

Then I'd suggest getting a Wilbers shock made for your weight and riding style. It completely eliminates the floating feeling the K bikes had on long high-speed-sweepers, and in general is an excellent choice for a performance shock.

That's about it. My bike was somewhat modified to use later model rims with radial tires - and the Z6 tires are wonderful - but they won't fit on your rims. If you are using the Dunlop K491 tire - you might consider going to a more performance oriented tire - such as a BattleAx BT45.

HTH,

[barryg]

When we get thru upgrading the all handling factors with this bike; I'd like to ride it. :clap

[r65lsk75c]

Thanks to all for the many suggestions for improving the handling of my '87 K75C. So, I'm looking at anything from a new rear shock to rebuilding my front end and swingarm to adding new tires. This would seem to involve a significant amount of $$$. Since the only dealer that I really trust is >60 miles from home, I'd like to do the work myself. This, in and of itself, is a bit of a problem. I've discovered over the years that I am much more skilled at taking things apart than I am at putting them back together. Therefore, I am somewhat intimidated by the thought of rebuilding the steering head or swingarm. I am fairly confident that I can change the shock. I will look into the shock (Wilbers or Progressive?). The tires (Metzlers front and rear) still have good tread, so I am reluctant to replace them now. Now, about new front springs, Progressive, Works Performance or a K75S spring kit? Does anyone have a part number for the factory kit to convert to an "S" front end. Is this a difficult conversion? Are there special tools required? I was very interested in the replies that mentioned lowering the seat. I would love to have the bike a bit closer to the ground as I also have a 30" inseam. Any other thoughts on this change. Can you install the shorter shock and not alter the forks?

I might consider offering a free ride to anyone who contributes a bona fide recommendation that leads to an improvement in handling!!!

I will await additional recommendations before taking action!

Rick T

[wndsrfr]

If you install a shorter shock on the rear, you will also need to lower the front, which is a piece of cake to do--took me about 15 minutes including finding the tools. All you do is loosen two allen head bolts on each side and the fork tubes will slide up in the clamps. Mine just touched the underside of the handlebar (RT model) at exactly 3/4". Just re-torqued the clamps and rode away with an entirely new feel to the bike. You can try this first without spending anything on front springs until you can evaluate the need for that step.

[barryg]

I think you got a lot of good suggestions. The thread on addressing the steering head bearings is good. With the fork assemblies off it's time to do that, also. Another good idea is adding fork boots/gaiters while the forks are off. These items may come off the BMW police parts list. They do a good job keeping the fork stancions free of nicks and scrapes that start the fork seals to leaking. Converting the bike over to S specs sounds good, but could be expensive. The S came with a built in fork brace, which required a two piece fender. It might be better to sell your bike and buy an S to start with. Just some ideas, good luck with you project.