MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: 75rtpaula on August 31, 2013, 11:44:12 AM
-
Hey all I've had my k75 for a few months now and it has recently had an issue where about every 3 seconds while in second gear the bike will jump violently as if an inexperienced rider is shifting without the clutch but it doesn't change gear, it is completely unbearable and I have found myself just skipping second gear all together any ideas what the problem could be?
-
is the shifter floppy or firm (test it by hand). It should instantly feel spring resistance both ways. If it has some slop then you likely have a loose Grub screw that connects it he shift lever to sungear that spins the shift drum. Hopefully its not fully engaging second from excess slop and jumping out. If its not that it sounds like you have lost a tooth on second gear. :(
Video about the grub screw.
BMW K75 K75S Clutch Spline Lube 2of3b (http://www.youtube.com/watch?v=zVea8TByyT8#)
-
The shifter is pretty firm, but I'm not sure just HOW firm it should be, wouldn't it behave the same in all gears if it was a problem with the shifter though?
-
Nope. Each gear has its own set of gears. Depending on the bevel some may pull into gear some may not.
That vid has a good visual on loose. Typically as the grub screw loosens shift issues will get worse.
-
These videos.... good info but watching gives me motion sickness.
-
the grub screw controls tightness of the shifter itself though, there isn't one grub screw for each shift ford is there? im kind of confused, i would think if the problem was with the shifter it would behave the same in all gears, but a problem with a single gear would be either in the shift fork, the mainshaft or countershaft gears, or the synchronizer of that gear, wouldn't it?
-
The grub screw gives sloppy shifts. The hope being 2nd is not fully engaging and lose Grub being a cheap repair.
If its not the grub screw then you might be shopping for a used transmission. Really wont know for sure till you get it open and inspect.
-
ok that makes more sense, do they sell rebuild kits for these transmissions? i would rather rebuild mine than put a used one in
-
Im not sure that they have a "kit" but the individual parts are easily ordered. I have been using http://www.bmwmcchattanooga.com/ (http://www.bmwmcchattanooga.com/) Lots of people swear by Max http://www.maxbmwmotorcycles.com/fiche/fiche.aspx (http://www.maxbmwmotorcycles.com/fiche/fiche.aspx)
Id compare parts lists and prices but I really think you want a used transmission. Just 2nd gear is $259. Thats ONE gear and you likely need its mate for another $259. Then might need some bearings seals ect......... You are well over $600 before you know it.
Frankenduck Kbikeparts.com lists a used transmission that is likely ready to go with 59k on it for $290 ;)
Beemer bone yard has a 50k parts transmission (damaged input splines from not doing spline lube) for $150 you could pull the gears out of. http://www.beemerboneyard.com/cotr.html (http://www.beemerboneyard.com/cotr.html)
-
well i took the transmission apart not that anyone cares :musicboohoo: (im kind of late posting on this considering i went for my shakedown ride yesterday) it turned out the 2nd gear side of the 1-2 shift fork was extremely worn down, put in new shift forks and lubed the splines and everything, replaced the transmission input seal while i was in there and discovered that 2 of the three tabs of my alternator driver were broken off, so all in all it was a much needed process for paula, she's back to being great now, and tomorrow i will be installing the new headlight bracket, headlight and turn signals