R100 RT transmission concerns (New owner)

[R100Todd]

I have a 1982 R100 RT and I've noticed that every now and then I hit a flat spot between fourth and fifth gear where it acts like neutral I also have the same problem between second and third gear does this mean I may need to do a transmission rebuild?
The bike is been well taken care of and only has 69,000 miles on her as far as I know the transmission has never been rebuilt.
Thanks for your help guys great to be here on the forum!
Todd

[Deleted User 62]

Hello Todd, do a search in this forum on "false neutral", you will find lots of information on this problem. It helps to press firmly on the shifter, a light tap will not always do it.

[R100Todd]

Thanks Tim!
Yes I found that a firm shift works more often then A soft shift for sure!
Thanks for giving me the best search term!
Todd

[Duane Ausherman]

Todd, welcome to the "home" so to speak. We are happy to answer your questions. If we don't know the answer, don't worry, we won't let you down. We just make up some answer to keep you happy.

The BMW transmissions are good for a lot of miles. They do have some quirks and expect to have to form habits that may be new to you. As soon as possible, drain out the hot oil from the transmission into something clean and inspect the oil and magnet.

I suggest that most of what you wish to know can be found with Google. Just always include "bmw motorcycle" and then the issue.

[R100Todd]

Thanks Duane that's one of the things I plan to do also plan to go to Amsoil full synthetic severe gear 90/140 weight I've had luck within my other bikes!
Yeah yeah I know it doesn't have to be Amsoil per-SE so it could be Mobil 1 or the other ones I just had good luck with the Amsoil so I kind of stick with it.
Todd

[Deleted User 62]

One thing to be aware of when switching to synthetic, a transmission that merely seeps with dino oil may flow like a river with synth. YMMV

[khittner1]

Not to start an oil thread, but unless its awfully flippin' hot where you are all of the time, 90W-140 gear oil is too viscous for an airhead tranny and drivetrain. The spec calls for 80W-90 in the gearbox, shaft, and final drive. I use Amsoil Severe Gear 75W-90, and it works fine.

Gear shifting on airheads is done most smoothly with a two-step shift lever movement; the first little dab up with the toe moves the bike out of the gear it's in, and a second dab or effort snicks it into the next higher cog. Sort of like double-clutching without releasing the clutch between shifter movements. It's inevitably a little slower shifting these things smoothly than it is on most Japanese bikes.

[R100Todd]

Ok I have read the posts that say the two step shift works well on these bikes but were they designed to be shifted this way?
khittner1 I see you're in Michigan and though it does get hot there I'm sure it's not as hot as here in Southern Maryland regularly. I also ride a lot to Georgia, Florida, and South Carolina. I don't want to run an oil that will damage the trans though so maybe the Severe Gear 75W-90 will be the best fit, I'll give it a try first then.
Thanks, Todd

[ME 109]

Not sure why some people find shifting an airhead tranny to be like a model T ford?
I can zip through my gears up and down just as fast as my ol' foot will go.
Edit, I don't have a flywheel tho'

[SteveD]

Another way to describe the two point gearshift technique is to call it gear lever preload.

The boot rests firmly against & under the lever without moving it. When the clutch lever is pulled the preloaded lever is snicked up a gear as the rpm is momentarily reduced.

Preload/clutch lever & rpm reduction/snick up is an almost simultaneous 4:1 action. Like Jeff's it should be able to change easily. To a newbie to the marque though, a little practice will be the go. Otherwise they can feel a wee bit agricultural.

Other than the preload thing, there's nuthin' different to what you might have been doing for years.

Don't forget to check for shards on the magnetic drain plug. Feel the stuff between your fingers. If it's soft, you're good to go. If it's sharp...get back to us.
I'd be happy to see this, but would still check for sharpness.


This one would melt my confidence then empty my wallet. It's not from an airhead, but you'll get the idea.