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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: jeffhestand on October 15, 2012, 05:28:08 PM

Title: Shifting throw/downshift
Post by: jeffhestand on October 15, 2012, 05:28:08 PM
My 85 k100 started having shifting problems on way home. The throw seemed to be getting longer and longer. By the time I got a mile from home it was not shifting well and it would hardly go into first from neutral.. What am I facing here.? I'm not quite done riding here in Missouri. Thanx jeff
Title: Re: Shifting throw/downshift
Post by: Inge K. on October 15, 2012, 05:42:31 PM
Happens now and then, get ready to open the gearbox. Search the forum with the word "grub screw".

Inge K.
Title: Re: Shifting throw/downshift
Post by: Rick G on October 15, 2012, 07:28:24 PM
Sounds like a gearbox teardown is in the wind. That rotten little grub screw backs out and eventually no gears at all.
Title: Re: Shifting throw/downshift
Post by: jeffhestand on October 15, 2012, 09:21:01 PM
Been lookin over tranny teardown info....couple questions... 1) how much time would this take...should I go ahead and just retire bike for winter and start the work.  2) with my headlight blinking off and on I know I will be cleaning the starter and such but would this be a good time to do the clutch spline drive and inspect the clutch etc.... What other maintain procedures should be done at this time ? Thanks jeff
Title: Re: Shifting throw/downshift
Post by: Rick G on October 15, 2012, 11:07:21 PM
It would take me 6 - 8 hours and that includes down time for eating and beer. If you are competent with the wrench and have not done it before then give a weekend. Otherwise serious down time and take your time.  You need to pull the starter motor to do the gearbox so include it in with the job, splines as well.
Title: Re: Shifting throw/downshift
Post by: frankenduck on October 16, 2012, 12:53:45 AM
IMO: Find a good used tranny and swap it in.
Title: Re: Shifting throw/downshift
Post by: wmax351 on October 16, 2012, 11:36:01 AM
IMO: Find a good used tranny and swap it in.

And then you could even fix your old one, and sell it. Or sell as-is to someone willing to fidget.
Title: Re: Shifting throw/downshift
Post by: jeffhestand on October 16, 2012, 12:23:08 PM
ok... that sounds good.  What is the best to find a good used "trustworthy " source to purchase said item.
Title: Re: Shifting throw/downshift
Post by: TimTyler on October 16, 2012, 02:45:31 PM
ok... that sounds good.  What is the best to find a good used "trustworthy " source to purchase said item.

You can try http://www.kbikeparts.com/#Transmission (http://www.kbikeparts.com/#Transmission)
Title: Re: Shifting throw/downshift
Post by: jeffhestand on October 16, 2012, 03:55:38 PM
I take it that buying one off Ebay may NOT be the best strategy? Also,,, i change rear drive seal couple months back, is getting to and repairing the tranny that much more complicated?
Title: Re: Shifting throw/downshift
Post by: Rick G on October 16, 2012, 08:34:53 PM
What I would be doing is to take the one you have and fix the grub screw and at least you have a known item. You don't know that if you buy a used one it's not going to happen 2000miles down the track.  As these bikes age I am seeing more and more of this type of problem.
And while I have it out inspect all the other parts like bearings and selector forks then you know what you have.
If you do the job yourself there is virtually no cost above some oil and grease if all else is OK.
Title: Re: Shifting throw/downshift
Post by: TimTyler on October 16, 2012, 08:42:16 PM
I am curious to know how much shift pedal vertical travel is ordinary on a healthy transmission.

I have about an inch of play.
Title: Re: Shifting throw/downshift
Post by: racinrich on October 16, 2012, 08:56:26 PM
searched grub screw only found it in this post?  :confused: like tim said how much is normal :confused:
Title: Re: Shifting throw/downshift
Post by: Rick G on October 16, 2012, 10:41:12 PM
Put it in neutral and there should be no slack or slop, but about 9/16 - 5/8 inch up and down free travel with resistance from spring loading.
Title: Re: Shifting throw/downshift
Post by: frankenduck on October 16, 2012, 11:13:29 PM
How many miles on your bike? (Just curious.)
Title: Re: Shifting throw/downshift
Post by: Rick G on October 17, 2012, 12:30:44 AM
Not sure if you mean me but 161,000km or 100,000 miles.
Title: Re: Shifting throw/downshift
Post by: Inge K. on October 17, 2012, 05:22:44 AM
searched grub screw only found it in this post?  :confused:

Strange, I found nine.........but most wasn`t that useful (and some about the ignition switch grub screw).

Here is some info: http://www.motobrick.com/index.php/topic,2579.msg14599.html#msg14599 (http://www.motobrick.com/index.php/topic,2579.msg14599.html#msg14599)
 
Suggestions on other places to search: http://www.motobrick.com/index.php/topic,2289.msg12458.html#msg12458 (http://www.motobrick.com/index.php/topic,2289.msg12458.html#msg12458)

Shog`s tranny thread, which could become useful...if dismantling (grub screw shown at end of post #11):
http://www.motobrick.com/index.php/topic,1808.0.html (http://www.motobrick.com/index.php/topic,1808.0.html)

Inge K.