I have a 1988 bmw k100 for context, if anyone has any advice it would be greatly appreciated. so two nights ago i left my bike outside and then is started raining extremely heavily & i was moving it inside and got stuck in the mud once, (not sure if that helps but i did not have this issue prior to this). today i am riding and i go to rev match before my down shift, and when i pulled the clutch in it would not rev above 2k rpm. i put it in neutral revved up to 6-7k and it sounds fine, then clutch pulled in first and wont rev above 2k once again. i continue on my ride because the bike is riding fine aside from that, then suddenly my speedometer only displays 0mph and i can rev again to downshift? any advice would be greatly appreciated.

It's hard not to laugh when it sounds that funny.

I'm thinking it rides normal so it revs normal, but the revs don't display normally, so maybe water in the instrument cluster making it go funny. The speedo drops to zero while riding, again the display is wrong, again maybe water in the cluster. Clean the mud off, let it dry, especially the cluster.

Yep that's a funny one.

Admittedly, it's easier than trying not to laugh at this one:

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.youtube.com/watch%3Fv%3Dkx_G2a2hL6U&ved=2ahUKEwjBu8aG1dCKAxUN9qACHRvuBJIQwqsBegQIDBAG&usg=AOvVaw3vKeuY5VVp9svgya-AmzSt

daveyson wrote:It's hard not to laugh when it sounds that funny.

I'm thinking it rides normal so it revs normal, but the revs don't display normally, so maybe water in the instrument cluster making it go funny. The speedo drops to zero while riding, again the display is wrong, again maybe water in the cluster. Clean the mud off, let it dry, especially the cluster.

Yep that's a funny one.

Admittedly, it's easier than trying not to laugh at this one:

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.youtube.com/watch%3Fv%3Dkx_G2a2hL6U&ved=2ahUKEwjBu8aG1dCKAxUN9qACHRvuBJIQwqsBegQIDBAG&usg=AOvVaw3vKeuY5VVp9svgya-AmzSt

it’s not just the cluster i don’t think, it was struggling to idle before i turned it off. and it genuinely wasn’t revving over 2k not just the display it was bogging down like it was going to die.

Yep, I'd still clean the mud off and let it dry. Maybe wet spark plug leads, coils and stuff. For some reason I have a picture of mud stuck in with the gear position switch and swing arm.

I wasn't going to weigh in on the rev matching comment by opening a can of worms, as it's a side issue. Then I thought, nup, it isn't, it's even a part of the title, so then I thought, screw it, let's do it.

Rev matching isn't achieved by revving the engine with the clutch pulled in, while downshifting, even though you sometimes see Hardly riders doing it.

The purpose of rev matching when downshifting is to get the engine output shaft and the gearbox input shaft to spin at the same speed when shifting, for ease of shifting and to reduce wear. So to increase the speed of the input shaft to match the engine, you need to put the gearbox in neutral, release the clutch, then rev the engine (now the gearbox input shaft and engine output shaft are spinning at the same speed) then pull the clutch, then downshift. It makes sense with a big truck hauling heavy loads, where it's simple to shift into neutral, but on a brick, I don't think it's worth it.

I hope this doesn't start a shit storm, as I know there are strong opinions on this one, on both sides.