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Voltaire 04-05-2013 02:11 AM

Transmission Differences
 
Probably been covered but I bought an R90/6 recently and I'd forgotten how clunky and resistant to change they are compared to the post 81 boxes.
Is it just the flywheel being lighter or is there differences within the transmission itself.
Although the heavy flywheel gives the 'vintage' feel I don't know if I can put up with it long term.
Other than " it is what it is" any thoughts?

motu 04-05-2013 02:14 AM

I was told it was the rider - so I am obviously a much better rider now than I was when I had the R60/5. Is your riding getting worse then ?

Voltaire 04-05-2013 02:22 AM

Quote:

Originally Posted by motu (Post 21113254)
I was told it was the rider - so I am obviously a much better rider now than I was when I had the R60/5. Is your riding getting worse then ?

Maybe I was spoilt with the R65..... what was that Joni Mitchell said.....:eek1

gsd4me 04-05-2013 02:28 AM

I've recently gone from an oilhead to an airhead and I'm lucky if I can make it through the first few gears without it sounding like I'm a novice.

motu 04-05-2013 02:50 AM

Quote:

Originally Posted by Voltaire (Post 21113268)
what was that Joni Mitchell said.....:eek1

We are stardust ? Oh yeah, we got to get back to the garden. On tomorrows list.

Plaka 04-05-2013 03:21 AM

Quote:

Originally Posted by Voltaire (Post 21113247)
Probably been covered but I bought an R90/6 recently and I'd forgotten how clunky and resistant to change they are compared to the post 81 boxes.
Is it just the flywheel being lighter or is there differences within the transmission itself.
Although the heavy flywheel gives the 'vintage' feel I don't know if I can put up with it long term.
Other than " it is what it is" any thoughts?

Time your shifts more carefully...and lighten the flywheel.

Also check your clutch cable adjustment. Nickel thickness of free play at the bars. If the shift lever pivot is worn and the lever sloppy, fix that. If the shift lever rubber is missing, replace it.

Past that (and running synthetic oil if you ever replace the seals) just dig the vintage feel...

kadesean 04-05-2013 03:34 AM

+1 on the timing. There are times when I just know my 1st to 2nd gear transition is going to be ugly, usually when leaving a light in traffic and I am behind a cage that isn't sure if it knows where the accelerator is. Prolly better for me to learn this and be patient, let the engine spin and shift a little higher in the RPM range. I find this to be the case on my '74 and on my '92.

Voltaire 04-05-2013 11:52 AM

Thanks guys, I'll have to rummage thru my Dads old box of coins to find a nickel...:D....that's the Jefferson bloke...?
Seriously though, the bike has only 66k kms on it so its most likely me...... and yes its only really noticeable in traffic in the lower gears.

Hey Motu, no chance of them putting up a parking lot any time soon down your way...

Padmei 04-05-2013 01:10 PM

Hey bro I suspect my old box was pre 81 & huge difference with that & my new one.

One tin soldier rides away

Stan_R80/7 04-05-2013 01:13 PM

A few things I noticed on shifting my 1978:

1. Preload helps considerably on upshifting.
2. Each gear shift must be complete before upshifting (i.e. preload is only good after completely in gear for a moment).
3. RPM's matter when downshifting. Syncromesh gears are not in the gearbox and the rider has to help synchronize the gears by keeping the RPM range where it would be for the gear selected.
4. Expect the transmission to clunk some. It's the way they were made.

YMMV.

Voltaire 04-05-2013 01:38 PM

I'm interested in what the differences are that contribute to the later ones being smoother, I took my latest purchase an 89 R100RT for a ride this morning and its quite a nice shifter ( by BMW standards)
Is it a matter of upgrading the selector mechanism or changing the flywheel/clutch/input/release mech or what?
Just wondering, I like to know how stuff works.:D

disston 04-05-2013 01:56 PM

The up dated shift mechanism will fit the early gearbox. It won't effect the clunkiness. The shift mechanism helps to prevent the broken detent spring and helps to eliminate false neutrals. I believe that's it. It is an improvement but you can still have false neutrals and you can still have a broken detent spring.

The majority of improvement in the feel and ease of operation is the lightened flywheel.

I think you made one illusion to a 1974 bike? This is a 1974 R90/6? If so you need to change the gearbox, flywheel & clutch and the starter motor.

The clutch carrier will be drilled for 11mm bolts in the crank so you have to have spacers made to accept the 10mm bolts or change the crank. Not sure what you do about the clutch carrier spacer that your early /6 doesn't have?

It was maybe a more common operation back in the day but every time somebody these days considers it they back out. I think it's not really worth it. All this time and money spent on a 38 year old rubber cow and instead you could be riding a Ninja. :lol3

ontic 04-05-2013 03:08 PM

Aside from everything else mentioned, I followed someones advice and added a significant percentage of 'Moreys Heavy Duty Oil Stabilizer'- it is sort of like thick oily snot. There is another brand of stuff I can't recall that offers a similar product. Very noticable improvement in ease of shifting and general transmission behaviour, not just on my bike but two other pre-81 bikes as well. Worth a try IMO.

Genrerally for me, 1'st second and back is rarely very pretty, for the 2nd to 3rd shift it gets sorted by a bit of care with preload and RPM and timing, 3rd to 4th is hard to stuff up and 4th to 5th nearly impossible to stuff up.
Running with a broken clutch cable for a while and having to clutchless shift teaches a lot about these boxes... and 1'st to second still sucks!

Voltaire 04-05-2013 03:35 PM

Quote:

Originally Posted by disston (Post 21117658)
The up dated shift mechanism will fit the early gearbox. It won't effect the clunkiness. The shift mechanism helps to prevent the broken detent spring and helps to eliminate false neutrals. I believe that's it. It is an improvement but you can still have false neutrals and you can still have a broken detent spring.

The majority of improvement in the feel and ease of operation is the lightened flywheel.

I think you made one illusion to a 1974 bike? This is a 1974 R90/6? If so you need to change the gearbox, flywheel & clutch and the starter motor.

The clutch carrier will be drilled for 11mm bolts in the crank so you have to have spacers made to accept the 10mm bolts or change the crank. Not sure what you do about the clutch carrier spacer that your early /6 doesn't have?

It was maybe a more common operation back in the day but every time somebody these days considers it they back out. I think it's not really worth it. All this time and money spent on a 38 year old rubber cow and instead you could be riding a Ninja. :lol3

Yes its a 1976 http://i129.photobucket.com/albums/p...psac5c409c.jpg
I'll probably leave it as it and live with it...My 73 R90 racebike has all the mods you speak of and yes there is no comparison. I pretend its a Ninja :rofl...Ninjacow...I like it.

I have however collected the parts to do dual discs and a S fairing ( not the one on it, that's a junk Emgo one).
Cheers

motu 04-05-2013 04:43 PM

When I had my /5 I'd ride around town and look to see if heads of any pedestrians turned when I changed gear - it was really embarrassing. One in ten shifts would be perfect - I'd kinda hope someone would notice that, it was such a real achievement for me.


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