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Gearbox & 2nd Gear Thu Jul 02, 2015 5:50 pm
TacKler
Life time member
Another issue which plagued me on my journey through the European Alps recently was the loss of 2nd gear. A quick search of the forum shows others have experienced this and instead of piggy backing old topics, mine is more of a solution not a question.
A few days before arriving in Lucerne, Switzerland, 2nd gear decided to play up by slipping out into neutral, and making a hell of a racket when engaged. Now it appears to play up when under load during accelerating and not when idling downhill.
One of the Swiss chaps of the flying brick forum explained the problem too me. There is a known problem with second gear and it is the result of hard acceleration and will manifest itself usually around 80-90,000km. But it is only second gear and only after continual hard usage. It is the result of I assume the selector pawl in the box – we could not translate the exact word from German into English. This part wears because it is the cheap part that BMW put in the gearbox. It will only happen to 2nd gear and no other. So if you ride the bike gently and not like a race bike then, there should be no problem. Perhaps that is why Motobins sells the 2nd gear selector pawl. As the 75 I was riding had 120,000 miles on it, then I think this failure is quite rare.
So if you are experiencing the same problem then the cheapest and easiest solution appears to be to just change the gearbox. Makes sense. The solution whilst riding is to just change up from 1st to 3rd which is a real pain when riding slowly through towns with pedestrians and traffic lights.
A bit more on the gearbox and the durability of BMW’s design. I also had a leak from the rubber clutch cover at the rear of the gearbox which was split/cracked presumably from sitting for a while. So there was a substantial leak whenever I stopped and it took me a while to realise what was going on. I was continually losing gearbox oil and unaware of it. We thought the oil leak was related to another problem on the bike as there was a lot of road gunge underneath.
There was also water in the gearbox resulting in a grey foam like mixture and as the level was good (checked far later) I did not realise this. It probably occurred during a day’s ride in heavy rain where water has managed to enter the gearbox from the top (seal from gear transmitter?). I believe Olaf has also experienced this. This is something I have never heard of occurring in the southern hemisphere.
As the gearbox contained mineral oil, it was a bit hard to track down as Europe has gone synthetic everything. I managed to find one litre of 80/90W from a small motorcycle dealer and when I found a suitable gravel layby, I polluted the clean Swiss environment by dumping a mixture of oil and water on the side of the road before heading off in the direction of Lucerne. Stiff s**t greenies, the 75 needed it.
Anyway, I didn’t know how long the gearbox level had been down or the water/oil mixture had been floating around inside but my guess is in the region of 3,000 miles. I also lost maybe another 200cc of new oil from the gearbox before arriving at the flying brick guy’s workshop. Considering all the Alpine riding and gear changes I had done, it just goes to show the durability of the BMW design!
On a side note the gearbox was re-filled with 75/140W synthetic and not mineral oil. No problems since!
These links show a bit more about the 2nd gear problem.
www.k100-forum.com/t7734-transmission-death
www.k100-forum.com/t7100-tearing-down
https://www.k100-forum.com/t9826-k100rs-gearbox
https://www.k100-forum.com/t8572-transmission-death-again
A few days before arriving in Lucerne, Switzerland, 2nd gear decided to play up by slipping out into neutral, and making a hell of a racket when engaged. Now it appears to play up when under load during accelerating and not when idling downhill.
One of the Swiss chaps of the flying brick forum explained the problem too me. There is a known problem with second gear and it is the result of hard acceleration and will manifest itself usually around 80-90,000km. But it is only second gear and only after continual hard usage. It is the result of I assume the selector pawl in the box – we could not translate the exact word from German into English. This part wears because it is the cheap part that BMW put in the gearbox. It will only happen to 2nd gear and no other. So if you ride the bike gently and not like a race bike then, there should be no problem. Perhaps that is why Motobins sells the 2nd gear selector pawl. As the 75 I was riding had 120,000 miles on it, then I think this failure is quite rare.
So if you are experiencing the same problem then the cheapest and easiest solution appears to be to just change the gearbox. Makes sense. The solution whilst riding is to just change up from 1st to 3rd which is a real pain when riding slowly through towns with pedestrians and traffic lights.
A bit more on the gearbox and the durability of BMW’s design. I also had a leak from the rubber clutch cover at the rear of the gearbox which was split/cracked presumably from sitting for a while. So there was a substantial leak whenever I stopped and it took me a while to realise what was going on. I was continually losing gearbox oil and unaware of it. We thought the oil leak was related to another problem on the bike as there was a lot of road gunge underneath.
There was also water in the gearbox resulting in a grey foam like mixture and as the level was good (checked far later) I did not realise this. It probably occurred during a day’s ride in heavy rain where water has managed to enter the gearbox from the top (seal from gear transmitter?). I believe Olaf has also experienced this. This is something I have never heard of occurring in the southern hemisphere.
As the gearbox contained mineral oil, it was a bit hard to track down as Europe has gone synthetic everything. I managed to find one litre of 80/90W from a small motorcycle dealer and when I found a suitable gravel layby, I polluted the clean Swiss environment by dumping a mixture of oil and water on the side of the road before heading off in the direction of Lucerne. Stiff s**t greenies, the 75 needed it.
Anyway, I didn’t know how long the gearbox level had been down or the water/oil mixture had been floating around inside but my guess is in the region of 3,000 miles. I also lost maybe another 200cc of new oil from the gearbox before arriving at the flying brick guy’s workshop. Considering all the Alpine riding and gear changes I had done, it just goes to show the durability of the BMW design!
On a side note the gearbox was re-filled with 75/140W synthetic and not mineral oil. No problems since!
These links show a bit more about the 2nd gear problem.
www.k100-forum.com/t7734-transmission-death
www.k100-forum.com/t7100-tearing-down
https://www.k100-forum.com/t9826-k100rs-gearbox
https://www.k100-forum.com/t8572-transmission-death-again
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Red 1991 K75S
