BMW K bikes (Bricks)

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duck

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From what I've seen in playing with lots of K bikes, I've seen much more spline wear on Z20 drive shaft splines than I've seen on Z16 drive shaft splines so it seems to me that a Z16 setup is better.


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Current stable:
86 Custom K100 (K75C fairing, K75 Belly pan, Ceramic chromed engine covers, 32/10 final drive)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
93 K1100RS
94 K1100RS
93 K1100LT
91 K1
93 K75S
http://www.ClassicKBikes.com
    

robmack

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Many design decisions are not based on technical merits. Most are financial and some reactionary to circumstances out of the manufacturer's control. Vehicle manufacturers are driven hard to minimize logistics and production costs wherever possible because of the ROI based on volume. The change from Z16 to Z20 could have been sparked by attempts as cost cutting measures where supply of cheaper 20-tooth splines was available to BMW. It could also have been a reaction to dwindling supplies of Z16 splines or closures of third party vendors which were producing sub-assemblies for the main plant.


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

Dai

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@robmack wrote:It could also have been a reaction to dwindling supplies of Z16 splines or closures of third party vendors which were producing sub-assemblies for the main plant.
Possibly not this Rob as big-block Moto Guzzi use Z16 drive shafts, so someone is still machining them. Not sure about the new V-series, but the older small-block were Z16 too. Only the IdroConvert used a Z20 shaft.


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'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

92KK 84WW Olaf


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You could both be right.

In the late 80s long before we had the Euro German to other Europeanexchange rates were going mad and if they were being sourced in a different country it could have had a big financial effect if exchange rates went wrong.


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1992 K100LT 0193214 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 81,400miles
    

Avenger GT

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The splines at t'other end of the shaft stayed at 16, so figure that one out. scratch

    

gladstone sa old fart

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@Avenger GT wrote:The splines at t'other end of the shaft stayed at 16, so figure that one out. scratch
The spline on the gear box end is held in place by a cir clip, no sliding movement.
I have just read somewhere a bloke in the USA makes up pinion gear splines longer then standard which
stops the wear at that end as well.
PJ

http://pjingladstonesa.blogspot.com
    

duck

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You can't stop the wear on splines that slide while under load. Lengthening them reduces wear, it does not stop it.

I think you may be referring to Bruno from Canada. According to what I've read on the BMWMOA forum he is no longer doing spline work due to some health issues.


__________________________________________________
Current stable:
86 Custom K100 (K75C fairing, K75 Belly pan, Ceramic chromed engine covers, 32/10 final drive)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
93 K1100RS
94 K1100RS
93 K1100LT
91 K1
93 K75S
http://www.ClassicKBikes.com
    

RicK G

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Those splines only slide a few thousandths of an inch at most. The moly lubricant serves as a cushion against the hammering they get due to the rapid changes in speed because the shaft only has one uni joint. Uni joints should be in pairs so as to minimize this action and that is why they need to be phased correctly to absorb the action the hammering effect. this is done by passing the action to the other and it gets absorbed without any damage occuring.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

k-rider

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I must admit that i. Didnt understand the speed change Thing, but here is a video Even i can understand
https://youtu.be/gmV4qwLfOMY

K-rider


RicK G

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As the shaft turns and the uni is at an angle the driven part slows and speeds up, as the uni goes over centre it tends to flick the shaft. this is only slight but is enough to cause a hammering effect at the spline because there is no uni at the other end to have an equal but opposite action and thus absorb the rise and fall in speed.
I really would have expected BMW to have taken this into consideration as it is one of the fundamentals when it comes to power transfer and shaft technology.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

k-rider

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Yes, i understand, thanks for explaining.
If i remember correctly, when Bmw introduced the paralever, the main reason was to avoid the driveshaft lift when accelerating, especially in corners, but shurely it would also give the rear splines A longer life?


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RicK G

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I have never seen the splines on a paralever destroyed in the way K100s destroy them. The rear section of the shaft attaches the same way as the front does with an internal circlip and the uni joints must be phased or at the very least you get bad vibration DAMHIK.
I have seen and heard of several rear unis self destructing but I have never had the opportunity of examining them but I am fairly sure that at least one was because the rear uni was not clipped into place correctly and it moved forward then got out of ballance and hey presto heaps of metal shavings.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

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