The Fatal K - flaws - Page 4 - - Excellence in Motion
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post #31 of 37 (permalink) Old Jun 21st, 2019, 1:57 pm
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K100RS - I disagree with most of the negative comments. I had two 1985 K100RS's, both bought new in 1985, one of them on a bike tour of Germany. I had intended to sell one of the bikes, but I liked them so much I kept both, until the first one was totaled in a wreck in 1987. The second one? I kept it as my only bike for 30 years! (With a 10-year layoff during children.)

I had customized the bike to eliminate some annoyances, so here is my short list of annoyances and what I did about them.
1. vibration causing heat shield to vibrate noisely, and eventually break the bolts. Replaced the stock bolts with bigger ones, basically. Not as pretty. but worked for 25+ years.
2. Handlebar grips too small - replaced with fatter Gold Bond grips.
3. Seat - replaced with Corbin seat. Everyone has one problem or other with almost every stock bike seat.
4. Heat from engine at slow speed (here's a real annoyance, especially living in Phoenix. ) - installed aftermarket fairing panels that sealed off the area under my knees.
5. Vibration - like every 4 cylinder I've ridden, it's buzzy at some speeds, very smooth at others. I avoided the buzzy RPM's. I think the K1300s is similar, but a small bit worse in the handlebars. (K1300s is MUCh better in the footpegs. I added grip puppies on the K1300s as I wanted to keep the stock warmers).
6. Gas tank heat. Apparently the fuel pump on a K100 recirculates a bit of fuel back from the engine to the gas tank. Or the heat just rises into the tank. Whatever, but on a hot day (100+F) that tank can get so hot my thighs were red after a ride. I wanted side panels on the tank, but never got any, so I just avoided pressing legs against the tank in slow, hot conditions.
7. Smoking at start up. SO annoying, an why didn't the engineers just flip the design so the heads were on the right side? MY solution was pretty simple. I *always* used the centerstand when stopped. No more problem, plus I didn't have to worry about the side stand sinking into hot asphalt.

After 30 years I didn't really trust the K100 on long trips anymore. It had died on me twice around town for failed fuel pump and once due to a broken ground wire. I decided to splurge on a new K1300gt and went to the dealer for a test ride. And found out they hadn't imported that model for years. So thought about a K1600, but they had no demos at that time. But there was this gorgeous K1300s MS... One test ride was all it took. I eventually sold the 1985 K100RS to the mechanic who worked on it for years for $1000. He had a primer red K100 tank in his garage already to replace the primer white one I had on. (Had to replace gas tank, all rubber bits, fuel injectors and a bunch of other stuff after letting the bike sit 10 years.)

In the follow pictures, you can see some of the mods I discussed above, plus rubber gaiters on the fork seals.
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post #32 of 37 (permalink) Old Jun 21st, 2019, 10:10 pm
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Originally Posted by phxazcraig View Post
7. Smoking at startup. SO annoying, and why didn't the engineers just flip the design so the heads were on the right side?
Seemingly an obvious solution which somehow didn't get considered.

Anyone know why???

If BMW bought the design from Peugeot, according to some, then maybe that design could only go in one way???


Last edited by Wildbears; Jun 22nd, 2019 at 11:20 am. Reason: Additional comment....
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post #33 of 37 (permalink) Old Jun 30th, 2019, 3:24 pm
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I had an '85 K 100 RS from new and put 70k miles on it. The only real issue I had was the engine heat on hot days, not much you can do about that. I solved the tingling hands by swapping the RS bars for a set off a "C" model. I never really had a smoke problem, must have been lucky I guess. Over the years I've owned a lot of other 4 cylinders and I wouldn't say the K series was any buzzier than the rest. My current K 1300 GT is electric motor smooth in fact.

I've owned 4 K bikes and 3 twins and honestly never had any trouble to speak of from any of them. I guess my '07 had some fueling issues on hot days occasionally but nothing to write home about.

Carpe` Throttelum - Loud Suits Save Lives

2010 K1300GT
2009 R1200GS (missed)
2008 K1200GT (sold)
2007 K1200GT (sold)
2002 R1150RT (sold)
1985 K100RS (missed)
1979 R100RT (missed)
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post #34 of 37 (permalink) Old Oct 15th, 2019, 4:37 pm
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post #35 of 37 (permalink) Old Oct 25th, 2019, 1:30 pm
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I had my Ducati radiator repaired. Drastically cheaper than a new one. This was done maybe five or six years ago, and it is still going strong. I believe I used these people.
They specialize in motorcycle and ATV radiators.
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post #36 of 37 (permalink) Old Nov 29th, 2019, 2:08 am
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I don't know what some of you are talking (complaining) about. I own a 1996 K 1100 LT SE with over 124,000 miles on it now. My bike has NEVER smoked off the sidestand. It is pretty smooth, and yes, adjust the friggen throttle bodies sometime, like someone else said. I have done 18 hour days traveling across the US only stopping for gas and nature calls, usually at the same time. Is it somewhat heavy, yes, big deal...learn to ride it. It is not a dog, I have hit an indicated 145 and climbing before I backed off a couple of times.
I love my K, I love touring around the desert southwest eating up the miles. Going places that others only dream of. It has everything I want /need and nothing I don't.
I use Michelin PR4 GT front and a Road 5 rear tire. (I now have over 13,000 miles on the present combo!!!) 120/70/18 and 150/70/17. Got Piaa fogs and Ohlin shock + hd front springs.
I use Mobil 1 15-50 oil/filter changed every 5,000 miles along with trans and final drive change w/ 80/90 synthetic.
If you are finding fault with your K, it probably has more to do with you and less about the bike. Would I buy another K 1100 LT? In a heartbeat. Only thing is this bike will probably outlast me.
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post #37 of 37 (permalink) Old Nov 29th, 2019, 6:21 pm
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Interesting reading, but seems to have gone a little away from the OP's question regarding fatal flaws....

IMHO the K41 bikes had no FATAL flaws (other than possibly the people who bought/rode them) but in time the design and specifications (including K1100 and K1200) were eclipsed by the competition and sales fell off. Sales are, for a company dedicated to making money, the prime driver and so Motorrad chose to move on rather than improve the design. We may entertain comments whether the basic design was improve-able at that point, but the fact that world-class engineering company did what they did, should serve to answer.
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