Kawasaki Sportsbike Riders Club - Australia - Online Forum

I seem to have misplaced my MA rule book - not easy to do in my pristine and well organised study.

I'm thinking about making a bigger front disc for the RD. My thinking is, if I make the disc bigger and make a bracket to move the caliper out, the area of disc contacted by the pads will be travelling at a slower speed and as such, the bike will be easier to stop.

However, I can't remember what the rule book says about brake modifications to a Period 5 historic machine. I think I can do whatever I want as long as the parts are from a period specific machine. How would this relate to something custom built?

Jase

you got this right...your theory?
surely the OUTER edge of a rotor is travelling FASTER then the inner edge of a rotor...at any given speed?
also
a larger rotor has a BIGGER/STRONGER gyroscopic effect on handling..than a small one

so moving the caliper outwards is a good idea? (ignore the rule book at this time)



cheers

Smitty

Hey I have my MA in front of me where abouts roughly would I fin that rule for you aardvark

Smitty wrote: surely the OUTER edge of a rotor is travelling FASTER then the inner edge of a rotor...at any given speed?

Of course you're right. That's my brothers fault. He filled me up with beer and home made scotch then made the ridiculous suggestion.

I don't really know what I was thinking.

Since I can't move the caliper in any further, then there's not much point discussing this any more.

Period 5
16.5.4.4 Front and Rear brakes:
a) Manufactured in the period, or
b) Which replicate those manufactured in the period.

Thanks Tinny.

I'm just looking for scabby ways to improve performance without having to pay for it.

Had I remembered my old physics lessons, I would have realised that the velocity of the circumference of a circles can be worked out by applying:
v = 2 πNR m/sec
Where v= velocity
N = revolutions per second
R= radius

Punching in the number quickly reveals the answer.

My brother and I had a conversation about increasing the disc size, friction area and a number of other options, that led to a state of overall confusion. Obviously I should have thought about this whilst sober before deciding to post.

No probs mate!

Been having probs all night with post reply starting to shit me this is the 5th time trying post again

However, it is certainly true that bigger discs WILL improve your braking. It's part of the theory behind Buell's front brake on their XBs.

Rusty wrote:However, it is certainly true that bigger discs WILL improve your braking. It's part of the theory behind Buell's front brake on their XBs.

It is to do with the swept area of the disc or rotor.


Neil

Rusty wrote:However, it is certainly true that bigger discs WILL improve your braking. It's part of the theory behind Buell's front brake on their XBs.

yes, and they counteract the gyrscopic affect by mounting the dics on the outer rim, so they can have a very lightweight rim and hub. there is a lot less stress on the rim as the brakes are grabbing right next to the tyre, so the whole wheel isnt twisting.

f@#king physics. or is is psycics?

Whack whatever you want on it . As said so long as it LOOKS like something made in the period . The arguements about floating discs in P5 roll on . I think there was suposed to be an Factory RG500 that had floaters in 1980 so the unlimited P5 boys with unlimited $ have floaters that look like RG stuff .
I think for us punters , a solid mounted disc , can be drilled , two piston caliper and master cylinder with the resevoir built in , not remote , will be fine .
Not sure about twin disc set up for the Elsie 250 , but would be a weight issue .
Going up to Deni today to work with Sir Al and putting a brembo caliper on my aircooled . The disc is off an XS 650 that had to be machined down to fit between the brembo . 300mm disc .
Had shiet brakes before with the same disc and a H%$da caliper , not opposed pistons .

Like you need brakes

So basically, if you can dig up a photo of a production bike from 1980 with wicked shit on(upside down forks, floating disks etc) it you can use it?

Stereo wrote:So basically, if you can dig up a photo of a production bike from 1980 with wicked shit on(upside down forks, floating disks etc) it you can use it?

in a nutshell - Yes.

The onus of proof is always on the competitor to prove that any modification or part was available or used in the period (for P5, thats 1.1.73 to 31.12.80). This is possible with period publications that actually *date* a product/modification etc....

Floating discs first appeared on Suzuki square four 2-strokes in 1976 - they have been around for ages. But the replica ones cost a motza !!

2 horizontal-bolt fork leg lowers ( the type that they currently try and ban) first appeared on a Munch Mammoth in 1968 FFS !!! And yet, some people on some forums do their level best to argue that this style of fork leg is a *Modern* style. What a load of frogshit that is.

Jase - up here, maximum rotor size for a P5 bike is 300mm. I think they finally settled on that size, as it was the biggest rotor available in the period ( and is actually from an XS1100 - you may want to try fitting one of these rotors to the LC mate, it could be the ducks guts !)

If you run a twin piston caliper (like a Brembo - one piston each side), then you can only run 1 disc. If you run stock single-piston sliding calipers, then you can run a twin-disc front end.

Gosling1 wrote:Jase - up here, maximum rotor size for a P5 bike is 300mm. I think they finally settled on that size, as it was the biggest rotor available in the period ( and is actually from an XS1100 - you may want to try fitting one of these rotors to the LC mate, it could be the ducks guts !)

If you run a twin piston caliper (like a Brembo - one piston each side), then you can only run 1 disc. If you run stock single-piston sliding calipers, then you can run a twin-disc front end.

Thanks Gos. I'll make some enquiries about disc size. 300mm could be just the increase in size I'm looking for. My brother is happy to make the disc and associated bracket for the caliper.

I looked at getting a twin pot Brembo, but a) they seem to be as rare as rocking horse shit and b) if someone does have one, they want some ridiculous amount of money.

I'm also told that if I go to the trouble of fitting a twin pot Brembo, then it is also a wise move to fit bigger forks. Not something I plan on doing at this point in time.

try and find a twin-spotter Brembo off a BMW - they cost 1/3 as much as the Ducati versions, are heaps easier to find, and are *exactly* the same caliper ! Bimmers from the early 80's had this style ( I think its called the 08 caliper ?).

In late-breaking news, you will be pleased to know that one of the LC's in the 4th dimension is getting a makeover over the Xmas holidays, one of the boys on CanberraRIDERS wants to go racing next year, he is a bit of a yammie fan.....so is going to have a nudge at P5 on a 350....