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Rear drive compatibility
- Thread starter 77158
- Start date
Polarbear
Polarbear
Drive shaft side check;
The splines may well be the same, but a look see will confirm this on the drive shaft side of the differential. No other issue, except shock mount to rearend must match, also. '81 was the first year for single sided swingarms on the GS800, but did the other models get it later? I think so. You cannot use a rear from a single sided swingarm on the '78, without some huge mods to the '78's frame, I think. I have a '78 R100/7. Randy13233
The splines may well be the same, but a look see will confirm this on the drive shaft side of the differential. No other issue, except shock mount to rearend must match, also. '81 was the first year for single sided swingarms on the GS800, but did the other models get it later? I think so. You cannot use a rear from a single sided swingarm on the '78, without some huge mods to the '78's frame, I think. I have a '78 R100/7. Randy13233
rear-end, final drive, differential, hinterradantrieb...
Mark, I can speak to the compatibility of drum style twin shock style final drives. I am running an 83 R100 final drive on my 78 R100S while I get its original (same ratio), 78 final drive re-sealed. I'm not a fan of rear disc brakes on these bikes so I canÔÇÖt speak to the interchangeability of the disc style final drives. I would have to assume they cross-fit and function simply because there are no other changes to the components that also interchange with the disc modles too like wheels, brake components, axles and so forth.
AntonLargiader
Active member
According to a BMW service bulletin, you'll have to use the brake shoes, cam and shaft O-rings from the later drive. So if they don't come with it, you'll have to buy them.
R
RRDavis
Guest
Exactly What Failed ?
Quote: "The starter quit working on a trip and I bump started it approx 5 times. That was curtains for the original rear drive with 78k miles."
Do you know exactly what failed? I'm curious about this because it doesn't seem to me that "bump starting" would be that much additional stress on the final drive and would cause it to fail. Does anyone who knows more have an opinion on this? I "bump started" a Volkswagen all one summer with no apparent consequences and drove the car for years after that.
Quote: "The starter quit working on a trip and I bump started it approx 5 times. That was curtains for the original rear drive with 78k miles."
Do you know exactly what failed? I'm curious about this because it doesn't seem to me that "bump starting" would be that much additional stress on the final drive and would cause it to fail. Does anyone who knows more have an opinion on this? I "bump started" a Volkswagen all one summer with no apparent consequences and drove the car for years after that.
AntonLargiader
Active member
Disks! Right. I was thinking drums. Disks, you will have to machine off the bumps of the wheel. That was also on the service bulletin.
kstoo
Huckleberry, Gilera &Toad
I am gonna guess that the final drive to wheel splines looked something like my 1980 R100 at 80k. From lack of maintenance or what (no history of PO) the splines looked like needle sharp triangles and I can thoroughly believe that if I had tried to bump start it they would have all sheared off.
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rear drive compatibility
I bump started the bike and rode the 90 miles home. When I got home I noticed oil leaking out the top vent. I opened the drain plug and metal bits came out. I have not diassembled it.
When I asked the BMW shop about bump starting they said "it's not recommended."
Can you comment more on the fins. The fins from my recollection of the pics are on the shaft side of the drive. The BMW microfiche lists the same part number for both bikes for the final drive.
I appreciate the info!
Mark Green
I bump started the bike and rode the 90 miles home. When I got home I noticed oil leaking out the top vent. I opened the drain plug and metal bits came out. I have not diassembled it.
When I asked the BMW shop about bump starting they said "it's not recommended."
Can you comment more on the fins. The fins from my recollection of the pics are on the shaft side of the drive. The BMW microfiche lists the same part number for both bikes for the final drive.
I appreciate the info!
Mark Green
B
BMWRich58
Guest
Hey Mark if it's any help,give a hollar over to Jonny the owner of Mr Moto in Chicago at around 19th and Western Ave. 312-738-4269
The former owner Bob had ton's of used parts all over and some of the old "airhead"tech's still work there. He does a lot of BMW work.
They should pretty much be able to give you an answer.
And are you a member of the Chicago Region Club??
if not PM me and I'll hook you up with the club info.
Here's the web site for the club.
http://crbmw.com/
The former owner Bob had ton's of used parts all over and some of the old "airhead"tech's still work there. He does a lot of BMW work.
They should pretty much be able to give you an answer.
And are you a member of the Chicago Region Club??
if not PM me and I'll hook you up with the club info.
Here's the web site for the club.
http://crbmw.com/
