www.zxrworld.co.uk

im on tha last step of a rebuild but im running out of patience with the bike im ashamed to say.
i cant get any real presure on the rear brake pedal beld it and bled it some more, tried hanging the caliper up and bleeding it. made a little differance.
the front brake only bites about 2cm from the bar. any ideas on how to firm it up bit?
thanks for any replys

what state are the front calipers in?possibly the pistons and seals need cleaning/replacing....
maybe master cylinder needs refurbing.....(i did this on mine and it made loads of difference)
could be all sorts

forgot to say the caliper have all new seals.
is the refurb kit hard to fit?

nah its pretty easy, just need some patience and circlip pliers.........if you managed to refurb calipers then your have no probs with master cylinder

cheers. may have managed it but it took longer than i care to admit!

what state are the discs in ? if they are getting thin the brakes will never feel sharp.. ditto the pads but to a lesser extent

had this conversation this evening with a lad i built a bike for last year

"my brakes feel toad, there's like loads of err ... play before they bite"
"do they still stop you ok, no fade ? not wooden?"
"nah they're fine"
"have you changed the pads or anything"
"nah.. why"
"cos you've done nearly 8000 miles, got through 3 back tyres, 2 fronts and a head-gasket .. perhaps they're just worn out"
"oh yeah"
"DOH"

'nother thing .. the back brake .. you have noticed the other bleed nipple right ?

has new pads front and rear. ive bled both sides on the rear.
the discs i dont realy know. they look ok t me but i dont realy know what to look for....

Here is what i have done so far to improve the quality of the breaking on my zxr400.

When i bought it they weren't awful, they stopped the bike ok, but the biting point was very late in the lever travel.

I started by removing the calipers and the pads and copper greasing all moving parts such as the pistons, this is to ensure that they move freely. I then ensured that the pads were ok (they were fine). Its always worth checking what pads you have as buying some good quality ebc or brembo sintered pads will make a difference.

I then checked both discs with a micromerter to ensure that they were well within limits. If they start getting thin braking quality will inevitably reduce.

I then bled the whole system thoroughly.

This was an improvement.

The next step was to rebuild the master cylinder. This probably took me about 40 mins and cost about £30. This has been the biggest difference so far. Again i bled the front brakes thoroughly.

I am now fitting braided hoses to both front and back brakes. I have fitted the back hose and my god what a difference. I had a wail of a time locking the rear wheel up and sliding all over the place last time i went out. Am hoping to change the front this weekend. The standard rubber hoses on most bikes (especially older ones like ours) are pretty crap and really ough to be changed, and changing to braided hoses is relatively cheap (has cost me £80 for front and back) and guarantees a lifetimes use out of the hoses.

If you are still having problems after this then the only thing i can imagine is a faulty caliper/s, in which case i would look at getting some new ones.

mxj560 wrote: I started by removing the calipers and the pads and copper greasing all moving parts such as the pistons, this is to ensure that they move freely.

err .. yeh .. cos copper grease and brake fluuid work well together eh ?

red rubber grease is what you should be using for that .. anything else will cause the seals to swell, and copper grease is an anti-seize compund NOT a lubricant.. think about it.. its got BITS OF COPPER IN IT

http://merlinmotorsport.co.uk/product_i ... m=Shopping

zimm wrote:

mxj560 wrote: I started by removing the calipers and the pads and copper greasing all moving parts such as the pistons, this is to ensure that they move freely.

err .. yeh .. cos copper grease and brake fluuid work well together eh ?

red rubber grease is what you should be using for that .. anything else will cause the seals to swell, and copper grease is an anti-seize compund NOT a lubricant.. think about it.. its got BITS OF COPPER IN IT

http://merlinmotorsport.co.uk/product_i ... m=Shopping

Do not use the copper grease lol.

Theres a link below to an overhaul guide for early VFR calipers.. you can ignore the bits that are caliper specific, such as sliders etc.. main parts to take note of is the grease used. red rubber grease on seals and bores.. only a light smear is needed.

Caliper Overhaul

The bits of copper will not only make your seals swell up like Zimm said but will probably scratch / wear away the cylinder bores as it grinds against the aluminium