Author Topic: F2 front brake upgrade??  (Read 2513 times)

470four

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F2 front brake upgrade??
« on: August 06, 2011, 08:53:30 AM »
Hi all,

My Cafe Yoshimura Four gets used often and enthusiastically...  ;D

The only problem being the bike is now quicker than its brakes? The rear brake is of course a necessity rather than a once-a-year MOT prod, I am looking at upgrading the front brake to an acceptable standard.

I saw MANY years ago a Four with twin discs - can't remember too much info but it had two left-hand forklegs with the relevent calipers etc running to an extra bolt-on disc on the righthand of the hub - all simple enough but this inverts your mudguard mounts, meaning welding & rechroming of my very shiny front mudguard... ::)

I have already upgraded to a braided line, the brake light switch being built into to the upgraded master cylinder, the disc has also been lightened to try to get some heat into what is basically a car disc, both size & thickness... :D

Im thinking of making a new swing-mount for a new twin-pot front caliper, has anyone done this already?  :)

Offline Bryanj

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Re: F2 front brake upgrade??
« Reply #1 on: August 06, 2011, 06:21:24 PM »
If this is the 400 F2 the only real way to get twin discs on it is fit the front end fron a CB400 twin, or you have to use two of the sliders with caliper brackets have one in front and one behind plus mod the mudguard as you said

470four

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Re: F2 front brake upgrade??
« Reply #2 on: August 06, 2011, 09:25:28 PM »
Anyone have any pics of the twin slider mod?

470four

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Re: F2 front brake upgrade??
« Reply #3 on: August 06, 2011, 10:20:52 PM »
Yay!







Brembo caliper conversion!

From these peeps...

http://www.mc-again.com/con_05.htm

470four

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Re: F2 front brake upgrade??
« Reply #4 on: August 06, 2011, 10:26:15 PM »
Sadly 89250 yen (

Online K2-K6

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Re: F2 front brake upgrade??
« Reply #5 on: August 06, 2011, 11:20:32 PM »
As you say the disc is quite a large size for performance.

I think there is more available from the standard caliper by using a mastercylinder with a smaller bore to increase your mechanical advantage and power through the std components.

The disc is only converting motion into heat, if you can't squeeze it hard enough you simply wont generate heat fast enough to wipe off the motion.

Alternative would be to use a more rigid caliper and make a one off arm to hold it on std fork leg.

470four

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Re: F2 front brake upgrade??
« Reply #6 on: August 07, 2011, 08:42:17 AM »
Was chasing Kevin from TTR400.com regarding him making some steel discs for a Four? The standard stainless disc is renowned for being too hard for most pads to get a grip on?

No reply as yet...  :(

Online K2-K6

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Re: F2 front brake upgrade??
« Reply #7 on: August 07, 2011, 09:50:06 PM »
I think what I'm getting at is from riding this sort of era when it was new some of them had a much better brake performance than others.

For example a Yam RD400 about 79ish year had a disc similar in size and material and single piston floating caliper but was much more powerful which seems to dispel some of the theories of why the Honda one felt less potent. The Yam had a much longer/spongier lever travel than the Honda which suggests that the mastercylinder bore was smaller to me but gives your hand a significant advantage over the caliper.

Extend that thought line to try a different master cylinder and you may get somewhere for reletively low cost and hassle.

 

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