Transmission problem!!

[fbenach]

I might be calling it the wrong way.... this is an image I got from the net...

The white circle piece had an "oval" shape and was somehow leaving my bike between gears...

[tvrla]

Thanks for clearing that up for me! It's what I thought you were describing. It's a roller that indexes the shift cam. If it's not working properly, it might not keep rolling to the valley between peaks - the point where gears are selected.

[fbenach]

Well, once again, I learn something new from you my friend!!!

I have another question... while we were doing this job, I talk to a guy that has some disarmed pieces of a 79 R65, I actually ended up buying from him a 31/9 final drive in good shape (I might be changing my crown), a couple of nice Krausers and front/back rims in good shape...

He does have two complete fork sliders and some other stuff...
What really got my attention was the following two items:
1. front/back 18" rims from what we suspect was a R60 of 1971
2. a sealed gearbox with kick starter from who knows what model.

How can you tell what kind of gearbox is this? Is there any code or part number on it that could identify it? I kinda wish it fits my 79 R65, I would love to have a kick starter!!!

Check it out!!!
And again, thanks!!

[georgesgiralt]

Hello !
All gearboxes are the same internally (same gears ratio) and same casing. So you could replace a ribbed tranny (5 speeds) by another one PROVIDED that the clutch are/was the same.
The heavy flywheel and the light one give a different input shaft on the gearbox.  So you have to measure the input shaft of the gearbox you plan to buy and check if it correspond to the clutch model you have on your bike.
If I were you, I'll buy the gearbox anyway, rebuild it (new selection springs, bearings and gaskets) adapt the input shaft to my bike if needed then put in place of my original. You will have to strip the input shaft to replace the internal front bearing race. So .....  
Of course for this to be cost effective, you have to buy it at low price...

[Julio A.]

The kick start lever looks a different than the one I have on my r65. The one on the picture looks straight while the one on mine has slight bends to clear the shift lever.

[tvrla]

The side opposite the kick lever - the one with the splined shaft out the center - has a date code on it. There's also a serial number on it somewhere but I don't recall where that would be. Both of those numbers will help identify the transmission.

I think it might be for the 1981 -> bikes, but not sure. They changed the outside ribbing when they upgraded the internals and the clutch but don't recall what the visual clues are.

If you decide not to get it, let me know - I want it!

[fbenach]

Wirespokes, that can be another possibility!! but take in consideration I am in Costa Rica!! the sending costs could be  little high...

Anyways, I am sure is before 1981... the question would be... will it fit somehow in a R65, otherwise, I will probably get it and put it on eBay!!

What do you think?

[tvrla]

You're probably right about shipping being prohibitive.  

Check the date stamp - that will tell you a lot. Also, you could measure the length of the exposed input shaft. I may be able to check the lengths of the different versions.

How about putting your location in your profile?

[fbenach]

OK, done!!!

I will check the dimensions on the gearbox!!!

here I found this link with some nice info on transmissions... Will read it carefully!!!
http://bmwmotorcycletech.info/transmission.htm

Thanks!!

[fbenach]

OK, went out to pick the tranny this evening... it has what appears to be a part number for the housing... 23 11 1 238 806

I searched for it on the MaxBmw site but nothing came up...
My mechanic feels it is compatible with my bike, as long as it seems to use the same clutch system than mine...

Any ideas where to check on this??

Thanks!!

[tvrla]

In the photo on the right side there's a circle with writing inside. I can't tell but it might say 82/83, which would be the year of manufacture.

I'm pretty certain this is the generation after yours.

[fbenach]

Yup!! I think you are completely right...
I found this on eBay, same numbers on a 84 R65!!!

Well, I´ll have to find someone who could use it!!!

http://www.ebay.com/itm/1984-BMW-R65-S-T-RS-R70-R90-R100-S273-transmission-trans-airhead-/290829200257?pt=Motorcycles_Parts_Accessories&hash=item43b6c56b81&vxp=mtr

[georgesgiralt]

Hello !
So as it seems, your gearbox is for a new, light flywheel.
But, as you know, these tranny are the weak spot. So if I where you, I rebuild the extra tranny swapping the input shaft to adapt to my bike/engine and stock it just in case mine broke.
The input shaft has to be stripped in order to change the input bearing inner shaft, and if the tranny has a high mileage, the splines at the clutch coupling could be worn out... so you may need to replace the shaft anyway...
This should keep you occupied for the  winter months...
But it is just me ...

[fbenach]

Thanks George, that makes sense!!!

I will have to sit down with the mechanic and see whats the state of this tranny... he has a couple of pre-81 units in the shop, so we will compare...

Thank you for the advice!!

[Bob_W]

The input splines are different. Later boxes had more splines. To my early morning and very old eyes, yours appears to be one of these. Also beware the kickers,  while seemingly a good thing are not very reliable on later boxes. Only for emergency use.
Bob