R90/6 trans trouble

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beemersanducs
Posts: 24
Joined: Tue Dec 28, 2010 3:24 pm

R90/6 trans trouble

Post by beemersanducs » Wed Oct 05, 2011 10:08 am

Hi all, returning from a ride Sunday the Cafe didn't want to down shift,lever would move but not catch after a few tries it worked, BUT about 2 blocks from home I could not down shift at all. My question is, is there a spring that goes bad or could it be something else?

Garnet
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Location: Victoria BC Canada

Re: R90/6 trans trouble

Post by Garnet » Wed Oct 05, 2011 10:20 am

What year is your /6 trans? The 1974 kickstart 5 speed is quite different from the 75 to 77 5 speed.
Garnet

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beemersanducs
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Joined: Tue Dec 28, 2010 3:24 pm

Re: R90/6 trans trouble

Post by beemersanducs » Wed Oct 05, 2011 10:32 am

Bike is a 1976.

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mattcfish
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Joined: Mon Aug 02, 2010 11:18 pm

Re: R90/6 trans trouble

Post by mattcfish » Thu Oct 06, 2011 12:43 pm

beemersanducs wrote:Bike is a 1976.
I've got a known good 75-76 tranny if you end up needing one. I can't give it away....but it could be substantially cheaper than trying to repair yours. PM me if interested.
Bellingham, WA USA
1975 BMW R90/6
1975 BMW 2002
1971 VW Westfalia
1985 VW Vanagon
http://advrider.com/index.php?threads/b ... s.1074183/

RickR90s
Posts: 38
Joined: Tue Apr 19, 2011 3:26 pm

Re: R90/6 trans trouble

Post by RickR90s » Thu Oct 06, 2011 4:46 pm

your shifter return spring has more than likely snapped. Very, very common on early 5 speed boxes. Happened to my '74 R90s and my buddy's R90/6, albeit at different mileages.

So if you're stuck in a certain gear, but the lever moves, that's probably it.

Tranny will need to be removed. Most guys install a shift kit which is an updated spring (stronger) and re-designed pawl to eliminate false neutrals. (My R90s has it after mine broke). I'm pretty certain that BMW only sells the newer spring anyway.

RickR90s

John Falconer
Posts: 78
Joined: Tue Aug 03, 2010 11:34 am

Re: R90/6 trans trouble

Post by John Falconer » Sat Oct 08, 2011 11:05 am

Rick is right, I believe, about only getting the newer spring.

However ... the new spring can fit too tight on some of the earlier boxes so check it for movement. Also, as others have said, installing the "shift kit" can be a very nice upgrade. There are three different cam plates - you really want the newest one. You'll also probably find the plastic roller that follows the track in the cam plate is toast.

As long as no gears are broken it is worth repairing - IMHO.

John Falconer

beemersanducs
Posts: 24
Joined: Tue Dec 28, 2010 3:24 pm

Re: R90/6 trans trouble

Post by beemersanducs » Sat Oct 08, 2011 5:38 pm

Is the "shift kit" a dealer item? if not where can I get one?

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George Ryals
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Location: Stone Mountain, GA

Re: R90/6 trans trouble

Post by George Ryals » Sat Oct 08, 2011 5:58 pm

I think the shift kit is NLA.

http://bmwmotorcycletech.info/transmission.htm About .7 way down on this page is all the information you could ever want about the shift kit and ita parts. Scroll down to NOTE!!!!!!!!!.....the shift kit......
Smile it's contagious!
'74 R90S, '67 /2 Conv w/sc, '66 R50/2
'74 Harley FXE, '72 Harley FLH w/HD sc
'69 BSA 441 Victor Special, '74 R90/6 Basket case
'85 R80RT wreck for parts

Dave Backmarker
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Re: R90/6 trans trouble

Post by Dave Backmarker » Mon Oct 10, 2011 6:46 pm

I'm about three quarters complete with rebuilding a R90S transmission. I'd suggest taking a look at http://www.cycleworks.net for transmission and flywheel tools and parts. Dan offers an excellent video that will take much of the guess work out of the job. The video goes into detail on removing and fitting new springs and pawls on the shifter mechanism. The video is $50 and will be money well spent as you'll see if you want to do this job. I've been a gear-head for 41 years and if you haven't taken apart a transmission before, this video will walk you through the process and also show you exactly what tools and jigs you'll need. And, if you pull the transmission, you may want to remove the clutch (special tools) to check on the diaphragm spring condition and clutch disc thickness and if you're doing that, you should pull the flywheel (read snowbum's work first) and check the main seal and oil pump seal.

I am not associated with Cycleworks. I'm a customer of Dan's machining work, parts and tools and have a great respect for his machining and welding skills.

DaveM
1975 R90S
2000 R1100RT

rapide
Posts: 3
Joined: Mon Jul 07, 2014 6:19 pm

Re: R90/6 trans trouble

Post by rapide » Wed May 30, 2018 1:06 am

''
Most guys install a shift kit which is an updated spring (stronger) and re-designed pawl to eliminate false neutrals. ''
In 2006 .... i had my tranny rebuilt by Oak. the COST for the ' SHIFT KIT ' was upwards of $6-700.oo just for the HARD to FIND PARTS. He machined the end cover and made a threaded plug to seal up the now completely removed K/S gears and ALL associated bits. these things are now very hard to get parts for R90 transmissions .

I suggest ........... remove the K/S bits

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