NC24 Brake calipers/disc/pads query

[Old Painless]

If i ever meet the previous owner of this bike again.....

Anyway, whats going on with my brakes please people, the pads dont seem to bite on the inner 1/4 of the disc so either the calipers are wrong or the discs are wrong or the pads are wrong, which wouldnt suprise me after the state of the rest of the bike. Exactly the same on both sides of the wheel. Thankyou !!

1987 VFR400R-H

[Neosophist]

Yeah they all dont bite on the inner most part, well none of the ones i've ever worked on do.

Discs / Calipers look standard O.E stuff.. pads are probably correct too.

Brakes must be able to slide though.. this is the biggest 'crap maker' of the brakes.. pull the caliper mounting brackets off and make sure the sliders are clean and greased with proper slider grease.

Pistons dont' usually sieze as their plastic.

£48 for a full set of new piston and caliper seals (including the sliders)

Then you'll need appropriate red rubber grease for pistons and seals and orange slider grease for the pins.. anything else is liable to make the rubber swell up, then your in for a world of trouble after the water gets in their and siezes it all solid.



^^ An example of a slider pin seal (Boot B) that has had fork fluid / brake fluid and incorrect grease on it.. wasn't keeping crap out and the calipers had siezed up.

[Old Painless]

So im loosing 25% braking power for no good reason ?

That cant be right .....

[Neosophist]

Technically no.. if you look at the pads you'll find they make full contact with the disc, there just smaller than the overall area of the disc.

The recent set of pads (Genuine Honda) that I took out that were worn down to the metal had worn off all of the braking material so they were making full contact with the disc.

It's just extra space on the disc. Your not loosing anything.

[Old Painless]

Okay, fair enough. Saves me buying new pads at any rate.

Just so i dont have to open another thread, the carbs my bike is running are 'VD' according to the letters embossed on the side, the manual says they should be CV ?

Oh i have a white and black wire connected to nothing just under the seat too. Bah, endless messing about.

[CMSMJ1]

CV = constant velocity

this is the the type of carbs

VD is the specific design of that model..

[Old Painless]

Are they supposed to be VD ? Im having some problems still. I have to set the idle around 2.5k or it stalls and cracking the throttle open quickly makes it bog and die instantly. I have tried pilot screw settings from 1.5-2.5 with mixed results, none good.

I have a mystery wire too. Black with a white stripe. Is there a clear wiring diagram for this bike ?

[l00k3y]

Pistons dont' usually sieze as their plastic.

£48 for a full set of new piston and caliper seals (including the sliders)

Then you'll need appropriate red rubber grease for pistons and seals and orange slider grease for the pins.. anything else is liable to make the rubber swell up, then your in for a world of trouble after the water gets in their and siezes it all solid.

Thanks a lot for this information! I've just replaced all the seals and rebuilt my master cylinder on mine and the left caliper was still binding, I was a bit clueless as the pistons all seemed in very good condition, with brand new seals, I've just remembered those slider pins were in a real bad state with the rubber grommit seal things all shot to bits. I'll sort out the pins as I have an MOT tomorrow and replace the pin seals soon.

[Old Painless]

I test the battery voltage when its switched off, 12v, when its at idle, 12v, at 5000 rpm, 8v. I think i need to check that one again somehow.

[Neosophist]

Pistons dont' usually sieze as their plastic.

£48 for a full set of new piston and caliper seals (including the sliders)

Then you'll need appropriate red rubber grease for pistons and seals and orange slider grease for the pins.. anything else is liable to make the rubber swell up, then your in for a world of trouble after the water gets in their and siezes it all solid.

Thanks a lot for this information! I've just replaced all the seals and rebuilt my master cylinder on mine and the left caliper was still binding, I was a bit clueless as the pistons all seemed in very good condition, with brand new seals, I've just remembered those slider pins were in a real bad state with the rubber grommit seal things all shot to bits. I'll sort out the pins as I have an MOT tomorrow and replace the pin seals soon.

www.jacksons-lair.co.uk/caliper.html

My guide on overhauling the VFR400 Nc24 calipers :)

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