R65 twin shock changes year by year

[r_kleinschmidt]

I'm working with the remains of a '79 and '83 twin shock R65s. I'm seeing differences in the subframe and centerstand and am not sure what else I'm likely to find.
Besides the change from twin shock to monolever, can anybody call out other significant changes in the twin shocks from one year to the next ?
Thanks very much for any info you can share.

Rob Kleinschmidt

[Tony Smith]

It is really only pre 1981 and post 1981 in terms of major changes.

The 1981 update saw bigger valves allowing BMW to untruthfully claim 50hp for the R65.

Other changes include -

Nicasil cylinders
Brembo brakes in place of ATE calipers
Hall effect ignition
Relocation of electrical services to RHS of main frame tube
Changes to the bottom pressing of the fuel tank to accommodate the new electrical services arrangement
Omission of the over-rev LED from the tacho (it never worked anyway)
Hall effect ignition
Double ended coil to work with the Hall effect system (the dreaded "crack-o-matic"

As you have already mentioned, changes to side and centre stand and changes to frame mounts to accommodate the new parts.

Rear ducktail and rear storage tray changed

Square master cylinder in place of round one.

Vastly improved rider footpeg mounts and gear linkage

Introduction of the "clutch carrier" in place of heavy steel flywheel (a massage vely retrograde stap on my view)

Gearbox input shaft shortened to suit clutch carrier.

I think the above is the major changes, there were minor detail changes such as fiddling with top put springs and other front fork damping components, but generally these were production changes to try and solve problems rather than fundamental changes.

After 1985 there were further massive changes as the R65 adopted the monoshock frame and was given the same wheelbase as it's bigger brethren.

Internally 1985 saw revised (and vastly improved) rocker arrangements.

From 1979 BMW fitted several different types of valve seats. All valve seats ever fitted to R65s are supposedly suitable for unleaded fuel, but some last better than others - if your valves are not receding use some lead replacement and leave them alone.

I will stop at this point, others will chime in.

[r_kleinschmidt]

Your advice is very much appreciated. Only thing that seems off is that my purportedly '79 forks have mount points for Brembos, not ATEs. Also trying to find a lower mount point for the '83 headlight bracket and not finding one on either set of forks. I will check the supposedly 1979 frame for location of the electrics. I have copied your commentary for future reference.
Regards
Rob

[Barry]

Here's a list I produced when I bought mine, it's not exhaustive. Lots of minor changes as well as the obvious ones.

The Ate and Brembo calipers were interchangeable with no difference in mounting.

A 79 R65 will have the electrics on the right hand side of the frame tube, they were never anywhere else on an R65. It was the type 247 airheads that had them in the headlamp shell.

 

[Tony Smith]

Barry, the electrical services arrangements are vastly different between  79 and 81 model which is why a 1979 tank cannot be fitted to a 81 and later - you can fit an 81 tank to a 79 however.

The ATE calipers fitted to R65s were actually made under a Brbo licence, a condition of the licence was to alter the pad retention system so that the pads would not interchange - this is fixable.

The only thing really "wrong" with the ATE calipers was the bone headed decision to use chromed mild steel for the pistons. After a couple of decades the chrome strips off, the piston corroded and the caliper stops working properly. Brembo sensibly used polished, anodised alloy which to all intents and purposes lasts forever.

I used to make stainless steel pistons for ATE calipers but I haven't for some years now as it was really only viable to turn up pistons in lots of 20 or so and there just isn't the demand anymore.

[Dwmadsen]

I read Barry’s exhaustive list of changes within models and find my 1982 R65 is in name only (the motor and frame are of that vintage, but it appears over the past 42 years, OP have made changes (no surprise).

My issue is the center stand and that while I’m the center stand both wheels are on the pavement (with the majority of the weight toward the rear of the bike). Rear tire is 4.00/18 and rims are OEM snowflake. I have a K-bike and R1100 and on both those bikes, the rear wheel is off the ground while on the center stand. Is the R65 center stand suppose to bring a wheel off the ground?

[Barry]

It's very common for the centre stands to go too over centre due to excessive wear at the tips of the stand where they contact the stops on the frame. Just get down and look at this contact point. The cure is to build up the tips with weld and then grind them back until the bike sits right with the front off the ground and some but not too much weight resting on the rear.  You will find the stand much easier to deploy once repaired.  Do a search on this forum and you will find a large number of posts on this issue and how to fix it.

In 81 and in even some bikes that perhaps sat unsold until 82,  there are examples of bikes that are a mix of pre- 81 and post 81 features. BMW were presumably using up the pre-81 parts. This may be the case with your bike