1979 r65 trannsmision and an 1986 r80

[bighairbrian]

Hi;

So I have confirmed the transmission on my 1986 r-80 (approximately 100,000 miles) is shot.

I have the option to purchase a transmission from a 1979 r-65 with only 25,000 miles on it.

Without tearing it off the r65, can anyone tell me if it will fit or if there are any major modification i might have to do?

a rebuild of the old r80 transmission seem like a costly alternative.


thanks for the input

brian

[Rob Frankham]

Hi;

So I have confirmed the transmission on my 1986 r-80 (approximately 100,000 miles) is shot.

I have the option to purchase a transmission from a 1979 r-65 with only 25,000 miles on it.

Without tearing it off the r65, can anyone tell me if it will fit or if there are any major modification i might have to do?

a rebuild of the old r80 transmission seem like a costly alternative.


thanks for the input

brian

Sorry mate, I'm 99% sure you can't use it... well without major work that is.

The problem is that the whole gearbox/clutch/flywheel was redesigned for the '80/'81 year. The big heavy flywheel gave way to a light 'clutch carrier' and the clutch itself was copmpletely changed. Unfortunately, this means that there were changes to the gearbox rear case, the clutch actuating mechanism attached to it, and the input shaft. This isn't just a matter of slight adaption, the clutch pushrod movement is much greater on the later mechanism. About the only sensible way you can use the earlier gearbox with a later engine is to transplant all of the flywheel and clutch components as well.. but this means that you'll inherit the old heavy flywheel and hard clutch mechanism... not a route you'll probably want to go down.

Rob

[SteveD]

The pn's change during 1980...b/w the 650's.
23002301792 RMFD-5 SPEED GEARBOX, KICK STARTER (to 09/80) $2219.72
23002301786 5-GEAR TRANSMISSION (from 09/80) $2042.14
85-on mono trans.
23002301786 5-GEAR TRANSMISSION $2042.14

You need a post 9/80 trans, even from a twin shock. Rob is correct.

[dwire]

The pn's change during 1980...b/w the 650's.
23002301792 RMFD-5 SPEED GEARBOX, KICK STARTER (to 09/80) $2219.72
23002301786 5-GEAR TRANSMISSION (from 09/80) $2042.14
85-on mono trans.
23002301786 5-GEAR TRANSMISSION $2042.14

You need a post 9/80 trans, even from a twin shock. Rob is correct.

Prices there Steve - does that mean those transmissions are still yet available? Just curious...

[SteveD]

I guess so. That's direct from the Max fiche web fiche thingee.

0130 here..'night.

[Ken in Oklahoma]

I guess so. That's direct from the Max fiche web fiche thingee.

I can't imagine that those transmissions would be available at those prices. Isn't a cluster gear priced at something like $1,500. And cluster gears for the older transmissions are no longer available--so it would seem unlikely would be able to sell new pre-1980 transmissions at all.

Ken

[dwire]

I guess so. That's direct from the Max fiche web fiche thingee.

I can't imagine that those transmissions would be available at those prices. Isn't a cluster gear priced at something like $1,500. And cluster gears for the older transmissions are no longer available--so it would seem unlikely would be able to sell new pre-1980 transmissions at all.

Ken

That's sort of why I asked. I have a (small) box full of NOS parts for the 4-speeds I "lucked" into. The notion that such things were not priceless was beginning to depress me.

[bighairbrian]

ok- thanks everyone for the infomration!

So, if things were redesigned for the 80-81 model year then this could be a match - form a 1980 r 80 rt>

http://cgi.ebay.com/ebaymotors/BMW-5-Sp ... 3367069937

thanks



b

[Deleted User 287]

ok- thanks everyone for the infomration!

So, if things were redesigned for the 80-81 model year then this could be a match - form a 1980 r 80 rt>

http://cgi.ebay.com/ebaymotors/BMW-5-Sp ... 3367069937

thanks



b

That box would need the same mods as the '79 R65.

[bighairbrian]

oops posted the wrong ebay link - should have been this one!

http://cgi.ebay.com/ebaymotors/BMW-5-Sp ... _500wt_923