1983 BMW R100RS Assemble Transmission

[@gentlerowdy]

i have no words to say how much of intrigue you have developed in me by presenting such a beautiful visual of an artistic video on the bmw airhead gearbox overhaul techniques- your work is to high perfection & i shall make an attempt to imbibe as much as you tried to put-forth fine details ..i would also like to thank you for generously giving the details of the special tools as well !!! with kind regards from india

[@BrooksAirheadGarage]

Rahul, Thank you for your eloquent and kind words. The best of success on your next airhead project. :-)

[@markfrancois1296]

I have rebuilt many BMW airhead transmissions for 74 - 76 model years. One question I have for you is this. When you measure the bearing surface below the measuring plate you show your depth gauge at the outer part of the bearing vs the inner race. I use the same Mitutoyo depth gauge you are using so I know that when the gauge anvil interacts with the bearing outer

[@nickwildsmith6537]

Excellent job

[@christianb4994]

Wirklich sehr detailliert und richtig gut in Ruhe erklärt. Vielen Dank dafür. Es ist so gut, das es sogar ohne Sprache gehen würde. Herzliche Grüße aus Deutschland. Das Video habe ich erst nach der Reparatur meines Getriebes gefunden. Meine ist auch von 83 und ich habe es genau so gemacht. Hat Spaß gemacht. Zum wärmen habe ich allerdings meinen Gasgrill mit Alu-Folie benutzt 😀

[@BrooksAirheadGarage]

Chrisitian, Gern geschehen. Ich hoffe, Sie fahren lange und lange mit Ihrem 83er. Bleib gesund und reite lange. 🙂

[@christianb4994]

@@BrooksAirheadGarage Hallo Brook, vielen Dank! Auch Ihnen wünsche noch lange viel Spaß mit ihren Motorrädern.

[@BrooksAirheadGarage]

@@christianb4994 👌😄

[@markfrancois1296]

Sorry, not sure why that posted. But what I am trying to say is that a new C3 bearings have about .002 "flex" in them and when the gauge anvil strikes using one ratchet, you will flex this bearing down by this amount. I actually take the measurement from the inner race which does not flex. Due to the output shaft, I have to measure the outer part of the bearing, but I use a flashlight and the lightest touch to make sure I am not depressing the bearing. I wonder if you can comment on this.

[@assessor1276]

Great job as always Brook and as always, I have a couple of questions: 1) How different were the shims after the rebuild from those that had been there prior to disassembly? 2) When you replaced the worn fifth gear - how does the ratio become taller with only one gear being replaced? I did hear you mention that the new gear has one less teeth - but it must also therefore have a smaller diameter and so wouldn’t you need a correspondingly larger gear on the intermediate shaft? 3) Given that the intermediate shaft is no longer available from BMW - what do you do if there is a bad component on it? (YIKES!)

[@thomasbirzer7729]

Thank you for sharing your Tipps and knowhow. Best regards from Germany, tom

[@BrooksAirheadGarage]

You're welcome Tom.

[@lastairhead]

nice job! found out some more detalis: nobody elese mentioned the flange and output shaft have to be oil free. It makes sense now, but it s always easier to pay attention when somebody mentions it! One question: on my 1992 model, the output seal is different and installed with the flat face towards rear. Is that correct? It was leaking when I bought it and only had 37 000km.

[@albeenamelast6620]

Well I just watch all 5 of the Transmission videos and I thought they were great!! Best Friday night I have had in a long time!! I started collecting photos of RS's and I have noticed that some have kick start levers on them. Are they /6 transmission and do you know if a /6 trany can go on even an RS from the 90t's. also do you know if the trany gears were changed in the later RS's or did they just change the gearing in the rear ends? Once again you have put out some very nice videos Thank you!!!!

[@BrooksAirheadGarage]

Hi Alan, I'm not an expert on airhead transmission evolution. In 1980, the R80 G/S came with a kick starter and the kick starter was retained in the R100 GS, so the transmission cover allowed use of one. The input shaft has another gear for the kick starter to engage. So, if the RS got a G/S (or GS) transmission, it would have the kick start lever. There were changes to the clutch design over the years. You can look at the differences on my web site (brook.reams.me) in the documentation of the 1973 /5, 1975 /6, 1977 RS and this 1983 RS to see the changes. The clutch and transmission parts have to mate correctly. Once again, I'm not an expert on the evolution and how much "mix-and-match" you can get away with. As far as I know, final drive gearing is how BMW adjusted the drive train, not changing transmission gears. That said, aftermarket supplies such as Sibenrock do make a taller 5th gear and I believe a shorter 1st gear. I installed the taller 5th in this transmission. You could read through Bob Fleischer's (aka, Snowbum) materials to find out more (bmwmotorcycletech.info/transmission.htm) I hope that''s helpful.

[@albeenamelast6620]

@@BrooksAirheadGarage Thanks for the info. Please keep up the build, love watching!!

[@nickbentley8760]

Fantastic level of detail Thanks!

[@BrooksAirheadGarage]

You're welcome Nick.

[@mohamedyousef9745]

Thank you so much Do you have any video or pictures for k1100 Rs ?

[@BrooksAirheadGarage]

You're welcome Mohamed. No I have not worked on the newer oil head models. I prefer working with airheads.

[@brainspace3133]

Awesome job mate.

[@BrooksAirheadGarage]

Thank you 😀

[@davidtoth4002]

I have a question. I have an r80gs 1990. When my rear output shaft bearing had to be changed, i realized that it was just one side closed (gear side open). Is this originaly possible? I assembled the same way, but im not sure it is good.

[@BrooksAirheadGarage]

BMW used plastic baffles to keep gear lobe in the bearings. New bearings often have two baffles instead of the original single baffle

[@davidtoth4002]

@@BrooksAirheadGarage thank you for the reply! So the way i assembled is also good, right?

[@roycampana4597]

Hi, So I just finished putting in the seal. I "tapped it in" using a socket and rubber mallet. There's still a small drip. Do you think I didn't seat the seal all the way in? Thanks for your help!

[@BrooksAirheadGarage]

Roy, IIRC, it butts against a lip so it only goes so far. If there is still a leak, that would lead me to look for scratches in the side of the hole the seal fits into or on the outside of the transmission output flange.

[@roycampana4597]

Thanks so much!