What if I built my own front rotor?

[Duc]

I am trying to improve front braking on my Cafe Racer (CB550 '76).

Have fitted braided lines, new pads, MC kit and still the braking is less than I would prefer. (Note the M/cylinder is 30 years old technology)

Original rotors are S/S and a large part of the problem I think.

I wondered "what if" if I had a rotor laser cut and drilled out of appropriate metal? What metal ?

I have also purchased a brand new Master cylinder (Ebay) that I intend to fit as soon as it arrives. Theory is better pressure with less effort and I can eliminate a pressure sensor switch in the centre of the line.

Tell me this is feasible and a good idea or otherwise

I would not expect laser cutting a disk to be too expensive and I can drill my own holes in my mates engineering shop.

[Morcs]

Iron works quite well I heard.

[Ixion]

Cast iron will give the best braking, but it rusts.

The engineering issue is not cutting it out, it's getting it dead flat and containing run out within the fine limits required. And having it all stay that way as operational heat cycles release residual stresses. Not easy

If it's for a road bike you'd need to get it LVV certified, also probably not easy (depending on the reputation of whoever does it)

Aftermarket brake rotors • the substitute rotors are:
– the same size as the OE rotors, and
– catalogued aftermarket items for that make and model of vehicle (and can include crossdrilled
and/or slotted types), and
– attached to unmodifi ed OE parts.

[HenryDorsetCase]

I am trying to improve front braking on my Cafe Racer (CB550 '76).

Have fitted braided lines, new pads, MC kit and still the braking is less than I would prefer. (Note the M/cylinder is 30 years old technology)

Original rotors are S/S and a large part of the problem I think.

I wondered "what if" if I had a rotor laser cut and drilled out of appropriate metal? What metal ?

I have also purchased a brand new Master cylinder (Ebay) that I intend to fit as soon as it arrives. Theory is better pressure with less effort and I can eliminate a pressure sensor switch in the centre of the line.

Tell me this is feasible and a good idea or otherwise

I would not expect laser cutting a disk to be too expensive and I can drill my own holes in my mates engineering shop.

the hot ticket in the day was a dual disc conversion (for 750's at least).

One of the things I looked at was something with a similar style, but doing away with the swinging caliper.... I never got round to it but something like a GB400/500 might work: might mean a whole front end transplant though.

the brakes on these are truly shit by modern standards, I agree.

[FROSTY:Me]

Your problem is just that --WHAT material do you use?
motorcycle brake manufactureers have been working on that for a heck of a long time.
My suggestion to you is not to bother
Rather than MAKE a disk make use of a disk that already exists.Perhaps one from say a 98 cb750
The Cruiser version of a few models seem to have single disks which may match
One trick we used to use on those thick and solid disks was to drill them to "sweep' the crap and watrer away

[Duc]

Thanx all.

I did a bit of homework with some brake and rotor specialists. There is a bit more to this than one would think. SO....

....anyone knows where I can find a rotor that might fit?

I had heard from a Post Classic Racer that some suzi rotors would fit and improve things (but I can not recall what model ! ).

I am going to reverse the forks and run the calliper on the back side. THis evidently improves things as well.

[HenryDorsetCase]

Its still the poxy old swinging caliper, though, right?

Don from Pitlane down here has got a CB750 he is building for CAMS, it has Brembos and modern-ish looking discs on it, but I didnt see the calipers on it when I saw the bike... might be worth an ask.

[FROSTY:Me]

If you don't need to stay "strictly" period my suggestion is to take matters one step further. Dump the whole front end and fit up the forks from a GB500 or even a SRV 250 might do.
Very similar looking forks, but you get 17 inch front wheel and heaps better brakes.As I recall the GB ahas shit loads longer forks than it needs too due to the legs going up and supporting the clipons.
My reasoning being -1) better choice of tyres. 2) spoked wheel will look period 3)HEAPS better brakes and 4)quick n eaqsy so you'll be back out riding faster.

[xwhatsit]

Its still the poxy old swinging caliper, though, right?

Yes. You didn't say anything about doing anything to the calliper, just changing the pads. Has it seized? I bet it's full of furry white shit.

Upgrade to a TLS drum SR400's a good'un!

[Duc]

I completely cleaned out the calliper before fitting the new sintered pads but yes ... it is the swinging calliper system.

When I get my brand new Master Cylinder , I will consider some new callipers if I can mod or bracket them to fit.

M/Cylinder I have bought - Ebay ($79 USD + 40 freight)

http://cgi.ebay.com/ebaymotors/FRONT...em120232141279

I do not want to change out the entire front end and hopefully can sort it all with lesser effort and cost.

[geoffm]

I have recently put PFM cast iron disks on the Beemer. Did improve the braking - cost was around $280/disk landed from the UK.
Geoff

[pete376403]

One hot setup in the '80s was to put Yamaha RD350 (dual opposed pistons)calipers on to bikes that normally had single piston swinging/sliding calipers.
Also cast iron rotors have a much higher co-efficient of friction than stainless, but gets a light coating of surface rust overnight, whereas stainless looks nice, even if it is crap in the rain.
A friend needed new rotors for a BMW K100 crash repair - had a couple made using Landrover flywheels (yes it involved a lot of machining but his friend worked in the toolroom at Mitsubishi Motors in Porirua and had access to stuff not normally found in the home workshop). They were excellent brakes.
This happened about 10 years ago, and no doubt would be impossible to get a WoF with today

[n0regret5]

brothers chopper has custom rotors front and rear, stainless steel. not too expensive, either. don't go for cast iron, as good as it is it rusts faster than a ginger kid in the sun and if you're racing with it, once its hot any water getting on it could cause it to explode..awesome, eh? stainless is fairly cheap and it'll last. if you get them made well and bung some sintered pads on, you'll have some beaut stoppers..