R65 (860) Brakes - 1150 upgrade?

[dogshome]

Hi all, The brakes on my bike are adequate (R65 dual discs, 38mm single pot pistons and 15mm master cylinder I believe). But a degree of planning is required. A stoppie is not on the menu. My brakes have been rebuilt, have fresh fluid and the lever is very firm with little movement required. But I have to mess 
* I saw this (first pic of what I consider an actually nice cafe racer).
* and then got these for a very reasonable price (second pic, R1100 dual pot calipers).

The ratio works out sensibly with the dual (smaller radius) pots and my master cylinder. With some drilling, reaming and possibly a little milling, look like they should fit. I can do copper brake pipes so that isn't a problem if the originals don't fit. Milling I can send away for with measurements and clear instructions, that is unless someone owns up to having a mill at work. They seem to keep 3D printers, lathes, bed saws, planers and other kit secret!

So WIP 

[dogshome]

Mounting centres the same. Other aspects look the same (but will measure). So I think it's just the lug offset axially to the wheel. Piccies below!

Thoughts?
Ideas!
Doom and gloom??

[Tony Smith]

I looked at fitting the 4-spot brakes but eventually went with K100 FO8s that came with the K100 front end now fitted (the 4-spots would be a bolt on if I could be bothered).

I was never comfortable with machining the forks and calipers to fit 4-spots to the R65 forks. From memory about 5mm is needed.

Someone advertises a stepped mount to fit 4-spots to Laverdas on eBay. Given that Lavs had FO8s this would work. But I'd make my own rather than pay his price.

[georgesgiralt]

Hello,
I saw this on ADVrider https://www.r90xdesigns.com/shop maybe you can contact them ?

[dogshome]

Hello,
I saw this on ADVrider https://www.r90xdesigns.com/shop maybe you can contact them ?

Very nice looking kit  ~$800USD with the required Ducati rotors. To give a sense of scale, I have a pair of nice 4 pot calipers with virtually new EBC pads for £50 

[dogshome]

I was never comfortable with machining the forks and calipers to fit 4-spots to the R65 forks. From memory about 5mm is needed.

I have measured about the same - 6mm on the RHS. I was hoping to take material off just the caliper, but that amount would definitely be dangerous. A couple mmm off the lugs and 4 off the caliper seems reasonable, but I'm thinking long and hard about that. Annoyingly the pic on Snowbums site shows exactly what I want to do, but no info or other pics about how it was acheived 

The Guzzi / Laverda adaptors at £100 a pair are a bit of a bargain. The Guzzi F08 look identical to the R65 caliper (with a slightly bigger piston) I think? My discs are 260 diameter, those call for 280, but I don't know where the guzzi lugs fall in relation to the axle. I might just email them. I can get later 4 pot calipers and it's a lot less risky than taking chunks off the brakes.


It might be easier to put a K100 front end on? Do you have a link to your conversion please Tony?

[Tony Smith]

There were photos of the K100 front end bring fitted, but I am not sure that they would tell you anything.

I will set out a few pointers though

The good news is that as far as the mechanical aspects go, fitting the K100 front end is a bolt on, same head stem bearings, same stem height - it is easy.

But, like all things there are complications to be aware of.

Firstly, if at all possible buy a complete K100 front end, in fact if at all possible remove the front end from the donor bike yourself. The reason for this is that the little bits you don't get will cost a fortune to buy individually on the 2nd hand market.

To that end you want the forks, triple clamps, handle bar mounts, brake fluid tube that goes down the centre of the steering stem.

Mudguard and mounts, calipers and hose mounts, front wheels axle and spacers.

The front "plate" from the R65 that mounts the lights and instruments needs to be cut at the bottom, the plate can be mounted usuinng bolt holes already in the K100 triple clamps but you will need to make your own spacers.

For brake lines I bought a braided stainless steel set that Motobins had on special - now I would buy Venhill.

Ok, now you still have a few decisions to make, the first being ride height. The K100 forks are both longer and have longer travel than the OEM R65 units. I decided to have approximately 1.5" of fork leg protruding above the top triple clamp as anything more looked a bit strange.

However my R65 is now  bit taller in the front end which meant I had to buy an r100 centre and side stand. The centre stand was a significant cost. In retrospect I should have paid a local engineering works to make the centre stand 1" taller and fitted a block to the bottom of the side stand.

Servicing the K100 forks is easy, they are really just overgrown R65 forks, or at least the very early ones I bought (complete with Brembo casting mark) were was.

BMW thought the front end of the early K100 was stiff enough to not require a brace - they were deluded, a brace is essential for enthusiastic riding.

You can still buy a Tarozzi brace, these are the gold standard but like anything made in Italy you will need a sharp mill file to adjust the fit.

Ignore anyone who bleats about altered geometry, they do not know what they are talking about. The K100 forks are of centre axle design and the triple trees are not offset.

Tyre wise I run Pirelli sport demons - 100/90-18 front and 110/90-18 rear. I love the handling.

There is probably more, ask me anything.

Your 4-spot calipers will bolt on and paired with a 14-16mm master cylinder will offer powerful breaking (I would fit a 14mm one which tells you how I like my brakes, my twin piston K100 brakes are run by the original 12mm master cylinder, it does good stoppies!

[Tony Smith]

Ok, ths is your fault.

I have been cleaning up my BMW parts holdings with a view to turning stuff I will never use into a small wedge of cash.

Sadly the hoarder in me has so far restricted the discards to a monolever type centre stand and some very badly internally rusted R65 engine guards (these will be going in the bin as I would not sleep at night wih the thought that someone might fit them to a bike.....

But on to the main event.

I the course of some recent horse trading I becamme the owner of an alllegedly junk 16mm master cylinder.

I intended to sleeve it down to 13mm and keep it as a spare, but when I pulled it apart all it needed was the crud removed from the recuperation port annd a new o-ring under the tank.

So now I have a working 16mm master cylinder.

Hmm....i thought.

A further rummage around the workshop located the items in the picture.

I have a new seal kit for them and new pads providing they take the samee pads as my 1150GSA.


So, guess what?

[Burt]

As an alternative to the K100 front, the preference would be for the K75 front.  The main reason is the handlebar to triple tree connection which is superior to the K100 setup as you do not have the vibration issue of the K100 and the use of bar end weights.  The rubber mount for the handlebar is a bad design as the rubber perishes over time whilst the 75 does away with those.  You also have the choice of different styles of K handlebars as well. 

Also there are two different types of K75 forks with one being Showa.  This also does away with the need for a fork brace as the 75 integral brace does the job with a two piece mud guard.  The four mounting points of the forward face of the triple clamp should be the same of both the K100 & K75. 

Tony, If you require any K series parts just give me a holler. 

[dogshome]

I'm back to plan A at the moment. See pic.

Tony, your calipers look in slightly worse condition than mine. Both much worse than my airhead calipers that are older, including the replcament I bought a couple yars ago. I guess we moved from "lovable classic" to "disposable utility" and it shows in how the bikes were looked after. Keith.

[dogshome]

Oh, the seals on these calipers are good. So they are being fitted as they are (IF the calipers fit). A seal kit appears to be £70 per caliper and repair kit with pistons around £120 per side!!! That's rediculous compared to a 20 year old Honda etc. Pads are reasonably priced, but the set that came with the calipers have less than 0.5mm of wear and are clearly printed EBC. My discs are not pristine, so the pads are going in too.

My nut and bolt fixing to the pillar drill is reasonable, but I was thinking - where can I find something about an inch tall, is square and with a perfectly right angle hole in it? Amazon appears to be flooded with these things in pairs for the price of 3 pints at the local:

[Tony Smith]

Burt I don't actually agree with you foor the following reasons.

Firsty the K75 model has become weirdly popular and the bike itself and anything to do with the K75 are far more expensive than K100 bits.

Secondly, there is the risk of acquiring Showa forks. I have had two sets of Showas blight my life, the first being the forks fitted to the KLE and the second being the forks fitted to the G650GS.

I will be happy to go the rest of my life without having to deal with Showa forks.

The early K100 forks, such as the ones I have, are casting stamped "Brembo", the later ones are Ficktel & Sachs.

Last comment, I sort of agree regarding the K100 rubber mounts on the handlebars, but when I was fitting the ones on my bike I visited my local Super Cheap Auto and rummaged through their bin of suspension bushes and bought some made from some sort of wonder material (they are blue in colour). I took a suprising amount of force from my 12 ton press to put the bushes in but there is no movement and I suspect those bushes will outlast me.

[Tony Smith]

Dogshome
So you want to start a "my 35 year old calipers are prettier than your 35 year old calipers discussion.

OK, you win! But I may be able to save you money.

There is a guy on eBay who sells Brembo fluid seals and dust seals, he sells them by dimension as they are intended to fit automotive calipers. No matter what they were intended for size is size and I have used him a few times to buy Brembo seals and dust covers - he will only use Fedex so the "post" is excruciatingly expensive, but his seals are around $US6 each! They are a light tan in colour and I was running a set in my R65 right up until I fitted the K100 front end with zero problems.

I also have a good supply of 123 blocks, most are strewn about my workshop, but one set, which I take great care of live wrapped in cloth in a drawer. Thery are my accurate $100 123 blocks, the others are $10 AliExpress specials. The cheapies are not used in machining anything I care about, although I have a yet to be executed plot to use my shaper to improve thhe accuracy of them.

I don't buy many tools from AliExpress anymore. Ask me about the set of ER32 collets I bought that proved to be a very false economy when their price was racked up against the end mills they broke before I realized what the problem was.

I am not the only person to be caught by the AliExpress $3 collets, recently my unrelated namesake on YouTube, "this old Tony" publised a video on the true cost of $3 collets. I draw some comfort tha someone as skilled and expereinced as hi got caught by them. but he did break fewer end mills than I did before he worked out what the problem was.

To bring this back to a slightly BMW related theme, I am gopi9ng to rummage in the local scrap yard's bins in the next few weeks to find some 1" steel flat bar or plate, I am going to use it to make a right angled fixture to mount on my lathe's face plate so that I can single point new exhaust threads onto airhead cylinder heads after having had them welded up. I have a number of cylinder heads acquired over the years that need new threads, I will turn them into money.

The last time I approached one of my country's "gurus" to see about cylinder head thread repair they wanted nearly $500 per head. I recokon I cann do them for a lot less and still turn a handy profit.

[dogshome]

RE seals, thanks again Tony I will look! I happily buy bearings, seals and O rings by size or type and hadn't thought about brake seals.

[Burt]

Fair comment Tony. 

The K75 is the pick of the litter mainly due to the smoother engine and it would appear that good clean K bikes are slowly starting to increase in price.  A year ago I upgraded the suspension on my K75S by having emulators fitted in the front forks plus a new unit on the rear.  A sort of a thirtieth birthday present for her.  The first serious trip between Urbenville and Tabulam destroyed the S fairing mount but the forks were fine. 

The F & S were the original 75 forks with later models fitting Showas.