Author Topic: Shift lever free play and the infamous Grub Screw - additional maintenance items  (Read 6741 times)

Offline riots100

  • ^ Proficient Motobricker
  • Posts: 167
After my last trip from San Francisco to Los Angeles down Highway 101, I noticed that I'm getting a substantial amount of free play in the shift lever.  Based on relevant posts here, it seems the shift lever grub screw is working its way lose in the transmission housing.  Also based on other posts, it looks like it might take a long day to fix, given the procedures that have been outlined elsewhere.


What I haven't found (which doesn't mean it doesn't exist) is a one stop list of items that I should take care of while I have the transmission separated from the engine.


Here is what I've gleaned so far:
- input spline lube
- final drive lube
- clutch inspection/O-ring replacement
- clutch cable replacement
- main seal inspection/replacement
- starter maintenance (clean brushes, etc)


Is this a good list?

  • Los Angeles, CA
  • 1992 K75, 2007 K1200GT, 1991 K100RS
----
BDJ

Offline The Mighty Gryphon

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  • ^ Quintessential Motobricker
  • Posts: 6223
With the transmission out it's a lot easier to work on the alternator and starter.  If you haven't done it already, it's a good time to check the starter brushes and clean the commutator and check the monkey nutz on the alternator.

Then you can do a swing arm bearing lube.  I took the opportunity to check the torque on all the fasteners and clean the alternator and starter connections as well.  Plan on checking the gear position indicator switch, and adding a grease fitting to the clutch arm as well.

Is your bike a K75?  If so, it would be a good time to degrease  the surfaces where the clutch hub contacts the balance shaft in the engine before assembling and torquing the clutch nut to 100ftlb.  This will assure you won't have what I call the K75 clank below 2200rpm.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS16V "Moby Brick Too"

Past:
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Martin

  • ^ Quintessential Motobricker
  • Posts: 4362

Also a good opportunity to waterproof the gear position indicator.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline riots100

  • ^ Proficient Motobricker
  • Posts: 167
I finally got to the inside of the transmission, you all were right about getting the grub screw back in.  What are some of the tricks to get it to start threading? (besides taking out all the guts of the transmission I mean...)


Also when I pulled the transmission cover off and started to have a look around, I noticed that I dislodged a ball bearing and a couple of races (I'm guessing here)  Anyone have any idea where this goes inside the transmission?


Thanks!
  • Los Angeles, CA
  • 1992 K75, 2007 K1200GT, 1991 K100RS
----
BDJ

Offline The Mighty Gryphon

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  • ^ Quintessential Motobricker
  • Posts: 6223
The "races" are actually rollers that go on the ends of the shift forks where they ride in the grooves of the shift drum.  They are #5 in the drawing.

The ball is probably the detent in the star wheel.  #11 in the drawing.



Can't offer any advice as to getting the grub screw started other than a steady hand and the patience of a saint.

 
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS16V "Moby Brick Too"

Past:
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline The Mighty Gryphon

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  • Posts: 6223
One other thing, you might want to slop some moly assembly paste on the shafts the forks ride on as well as the rollers and the grooves they go into.  The paste will help hold things together and make shifting a bit easier as well.

Do it after you get the grub screw in so the paste doesn't interfere with the Loctite on the grub screw.  You did clean all the threads real well with brake cleaner, didn't you?

Wish I could tell you more, but it's been three years since I did mine. 
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS16V "Moby Brick Too"

Past:
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline The Mighty Gryphon

  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 6223
Still thinking about this:  Do you have a ball end Allen wrench?  It lets you drive the screw from a bit of an angle.  A small dab of very thick grease in the socket of the screw helps to hold it on the end of the Allen wrench.  Also, a small pick up magnet to retrieve the screw when you drop it into the innards of the transmission(I must have dropped mine 25 times). 

Keep the brake cleaner at hand so you can keep those threads super clean.  You are probably aware that you never want to do this job again and you want that Loctite to do it's job.  After you get the parts installed, before you put the case together, take some paper towels and soak up as much of the brake cleaner that is in there as possible.

Last, don't try to rush the job.  If you feel like you're getting frustrated, take a break.   
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS16V "Moby Brick Too"

Past:
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline billday

  • ^ Quintessential Motobricker
  • Posts: 1341
This thread is giving me flashbacks.

Not pleasant ones.
  • New York State, USA 10977
  • 1985 K100

Offline The Mighty Gryphon

  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 6223
PTSD...

...Post Transmission Stress Disorder
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS16V "Moby Brick Too"

Past:
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline billday

  • ^ Quintessential Motobricker
  • Posts: 1341
. . . but it didn't kill me.
  • New York State, USA 10977
  • 1985 K100

Offline DirtyDR

  • ^ Motobrick Curious
  • Posts: 64
Take lots of pictures, as soon as it warms up a little I need to finish tearing mine down so I can do the same.
  • Edwards, CO
  • 1985 K100RS, 2003 R1150GS, 1994 R1100RS, 2006 Ural Patrol, 1999 Rokon Ranger

Offline gone_ape

  • ^ Proficient Motobricker
  • Posts: 135
  • 94 K75RT (Now Standard)
Did somebody mention the "Clutch Arm Boot Inspection? (for splits in the rubber)... When I had the trans out, I replaced the seals just as a matter of they were probably 20+ years old....(input, output, gear change shafts, the gear  indicator seal etc etc. Motobins sells a seal kit complete....very handy)..the transmission shafts are straight forward to remove as a unit - just be careful not to mix shims!!!
  • Austin, TX
  • 94 K75RT (Now Standard)

Offline Kai Ju

  • Motobrick Curious
  • Posts: 34
To make it easier to start the grub screw, simply move the lever it threads into. This will give you a straight shot at the screw hole.
Make sure everything is grease and oil free, and be sure to apply red Loctite to the screw.

Once you get the screw started, release the lever and tighten the screw down by hand with the ball driver. Then take a short Allen socket, with an extension, and torque it to spec while holding the lever so you get a straight shot at the screw. You can now actually use the shift lever to get things lined up. The reason I mention short Allen socket is that you will loose torque if you use a long one due to the bit twisting. Use 3/8 drive tools over 1/4 drive for the same reason.
Don't forget to remove the small freeze plug in the cover so you can poke through that hole to get the detent lever installed when you lower the cover. It's best to replace it and use some Honda or Yamabond to seal it at installation. Just push it in until flush with cover. BTW, if your shift shaft seal is leaking, this is the best time to replace it. A word of caution though, if the grub screw was loose for a while, there will now be a burr around the tapered hole on the shift shaft that the screw fits into. This may make it difficult to remove the shaft.

I once got to do this job twice on the same bike, the second time for free. :mbird
That's when I learned that just screwing it back in and tightening it with a ball driver is not enough.
  • SoCal
  • '85 K100

Offline The Mighty Gryphon

  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 6223
To make it easier to start the grub screw, simply move the lever it threads into. This will give you a straight shot at the screw hole.
Make sure everything is grease and oil free, and be sure to apply red Loctite to the screw.

Once you get the screw started, release the lever and tighten the screw down by hand with the ball driver. Then take a short Allen socket, with an extension, and torque it to spec while holding the lever so you get a straight shot at the screw. You can now actually use the shift lever to get things lined up. The reason I mention short Allen socket is that you will loose torque if you use a long one due to the bit twisting. Use 3/8 drive tools over 1/4 drive for the same reason.
Don't forget to remove the small freeze plug in the cover so you can poke through that hole to get the detent lever installed when you lower the cover. It's best to replace it and use some Honda or Yamabond to seal it at installation. Just push it in until flush with cover. BTW, if your shift shaft seal is leaking, this is the best time to replace it. A word of caution though, if the grub screw was loose for a while, there will now be a burr around the tapered hole on the shift shaft that the screw fits into. This may make it difficult to remove the shaft.

I once got to do this job twice on the same bike, the second time for free. :mbird
That's when I learned that just screwing it back in and tightening it with a ball driver is not enough.

This post should go into the Lieberry.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS16V "Moby Brick Too"

Past:
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline riots100

  • ^ Proficient Motobricker
  • Posts: 167
It took a little more time get it fixed than I wanted due to employment constraints, but I got everything back together and running in tip top shape.  Many thanks for the very helpful suggestions along the way.


My solution to getting that screw back into place was to take out the input shaft and shifting drum and detach the spring on the ratcheting arm.  Fortunately I am not risk adverse in taking things apart.  It helps me to understand the intertwining mechanical aspects to the system.


With the relatively empty transmission housing, I was able to get my hands down to where the screw goes in and get the grub screw started.  The rest was just following directions and looking at my reference photos in putting it back together.


I checked the clutch, lubed all the splines, cleaned the starter, checked the alternator, etc. and generally cleaned everything before it went back together.  Then I went out on a test ride.  The shifting on that bike has never been as smooth and tight.  I think that grub screw was loose from day one when I acquired the bike.  Went on a longer ride in the Santa Monica Mountains without issue.  I think she be fixed.
  • Los Angeles, CA
  • 1992 K75, 2007 K1200GT, 1991 K100RS
----
BDJ

Offline The Mighty Gryphon

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  • ^ Quintessential Motobricker
  • Posts: 6223
 :clap: Getting that damn screw back in there is one of the most satisfying jobs you can do on your bike.

I would guess that the feeling of accomplishment accompanied by the radical improvement in the quality of the shifting certainly made all the grief worthwhile.

Nice job!
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS16V "Moby Brick Too"

Past:
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

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