FORUM

Notifications
Clear all

Gearbox Oil!

6 Posts
4 Users
0 Reactions
13 K Views
Marcus Priddy
(@marcus)
Posts: 23
Eminent Member
Topic starter
 

Hey all :woohoo:
Just changed my gearbox oil to Royal Purple 75W90...
...It's really really nice!
Shifts were previously a bit crunchy πŸ™
Now it's like butter!!!
Seriously, I've got a noticeable improvement.
...Couldn't help but share
I'd recommend it to all.
Cheers!
-marcus

 
Posted : 04/15/2016 14:12
Bradley Barrus
(@895)
Posts: 34
Eminent Member
 

I added a small percentage of Dow Corning Gear M to the gearbox on my R75/5 and there is less metal on the drain plug during oil changes.

 
Posted : 04/28/2016 22:57
Dave Rankine
(@354)
Posts: 8
Member
 

Isn't that Royal Purple synthetic? The conventional wisdom is that synthetic in a bike that old is going to result in seal problems down the road. Dave

 
Posted : 05/01/2016 21:13
Marcus Priddy
(@marcus)
Posts: 23
Eminent Member
Topic starter
 

Isn't that Royal Purple synthetic? The conventional wisdom is that synthetic in a bike that old is going to result in seal problems down the road. Dave

In the early days of synthetic lubricants, leaking did occur. The modern versions don't have the same problems. BUT (there's always a but), if your seals are old and worn out, they're going to leak because they were going to leak anyway. Replace them with the current versions from your BMW dealer, most of which have been updated to incorporate better materials and lip designs.

Agreed! My main seal and pushrod tube seals are crapping out for sure. Looking forward to replacing and cleaning up the mess!

Thanks for the comments

 
Posted : 05/04/2016 18:23
Richard W
(@wobbly)
Posts: 2549
Member
 

Agreed! My main seal and pushrod tube seals are crapping out for sure. Looking forward to replacing and cleaning up the mess!

The push rod tube seals aren't the typical "lip seals" used around rotating shafts which are the topic here. Those seals fail for an entirely different reason.

Push rod seals work by being a compliant synthetic rubber. As such they exert a small pressure between the bottom of the push rod tube and the engine case. Due to the aging process of this particular material, the seals tend to loose their resilience. As they harden, they no longer push against the mating parts to make an effective seal. This "hardening" is an effect of heat and time, irregardless of engine oil weight, type, or brand.

The 4 seals I installed were easily compressible several millimeters by hand, the ones that came out were of the same durometer as stone. So the change is quite dramatic.

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 05/07/2016 10:23
Marcus Priddy
(@marcus)
Posts: 23
Eminent Member
Topic starter
 

Agreed! My main seal and pushrod tube seals are crapping out for sure. Looking forward to replacing and cleaning up the mess!

The push rod tube seals aren't the typical "lip seals" used around rotating shafts which are the topic here. Those seals fail for an entirely different reason.

Push rod seals work by being a compliant synthetic rubber. As such they exert a small pressure between the bottom of the push rod tube and the engine case. Due to the aging process of this particular material, the seals tend to loose their resilience. As they harden, they no longer push against the mating parts to make an effective seal. This "hardening" is an effect of heat and time, irregardless of engine oil weight, type, or brand.

The 4 seals I installed were easily compressible several millimeters by hand, the ones that came out were of the same durometer as stone. So the change is quite dramatic.

Thanks Wobbly that makes sense.

 
Posted : 05/12/2016 13:08

Advertisement

Scroll to top