R90/6 trans trouble

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Beemerboff
Posts: 48
Joined: Thu Feb 08, 2018 12:11 am

Re: R90/6 trans trouble

Post by Beemerboff » Thu May 31, 2018 12:05 am

I would jump at a good used box, never know what you are going to find until you pull the end cover off and as someone has already said gearbox parts are either NLA or uber expensive.

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jagarra
Posts: 809
Joined: Mon Dec 26, 2011 12:42 pm
Location: Reno, Nevada

Re: R90/6 trans trouble

Post by jagarra » Thu May 31, 2018 9:23 am

Here is a picture of the parts associated with the shifter, seems all the items have a price listed even the old style ones, so maybe they are available. Sometimes one doesn't know it till you get the sad call from the dealer.

https://www.ascycles.com/DesktopModules ... 624351.gif
1974 R90/6 built 9/73
1994 BMW R1100RS
1964 T100SR Triumph
1986 Kawasaki Concours

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Gibson
Posts: 156
Joined: Tue Apr 19, 2016 11:45 am

Re: R90/6 trans trouble

Post by Gibson » Thu May 31, 2018 1:32 pm

That happened to me with my 81 R65. I took the tranny out, put it on the bench opened it up and it was the shift spring that broke. A cheap part, but a fair amount of work. I believe this happened at about 30K miles. Never had another problem. I ran it to 68K miles then sold it.

Beemerboff
Posts: 48
Joined: Thu Feb 08, 2018 12:11 am

Re: R90/6 trans trouble

Post by Beemerboff » Thu May 31, 2018 11:35 pm

I had the same symptoms, opened the box and found the output shaft bearing had collapsed and the box was effective scrap.
Which is why I suggested graciously accepting the offer of a replacement box.
The worst that can happen is that you wont need it, and you will have a spare box as long as you are riding airheads.
By then you should have no trouble selling it again for the fight price.

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Gibson
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Re: R90/6 trans trouble

Post by Gibson » Fri Jun 01, 2018 9:29 am

Yep, a spare gearbox is a win win :!:

Wobbly
Posts: 247
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Re: R90/6 trans trouble

Post by Wobbly » Sat Jun 02, 2018 9:31 am

jagarra wrote:
Thu May 31, 2018 9:23 am
Here is a picture of the parts associated with the shifter.....

https://www.ascycles.com/DesktopModules ... 624351.gif
• Item #4 returns the shift lever to the central lever position, in anticipation of the next shift.
• Item #7 keeps the indexing pawl in contact with the shift cam.
• Item #17 adds pressure to the roller detent to locate the shift cam at the proper location.

It is probably most prudent to open the g/b you now have and survey the damage. The extent could be major or minor. If major, then you have the offer of the backup g/b. But owing to the labor to even get at the g/b, that box should also be opened and inspected.

Since all springs loose tension and can fatigue over time, it is best practice to replace 40 year-old springs with new (and possibly improved) springs before re-installing a gearbox. That is to say, the cost of getting at the springs is 10X the cost of the replacement parts.

Hope this helps.
After 20 years as a professional bike mechanic and 30 years as an engineer I know just enough to be dangerous !

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