As I've owned my silver
Traveller for over 12 years now, I thought it was time I started
writing about some of the modifications I've done to it.
First article will be
on the replacement of the standard Grimeca front brake master
cylinder and caliper with Brembo units.
Before I start, the
usual disclaimer applies – if you do any of the things detailed
here and it goes wrong, don't blame me. You're big boys and girls, so
you should know whether or not you're competent enough to do the
work. If not, get someone else to do it. OK?
I did this modification
four or five years ago, so it's been well tested. In that time I've
been to the Alps a couple of times, so I've been up and down roads
that look like this:
The standard Grimeca
setup works very well, but is basically a cheaper copy of a Brembo
and isn't as well made. It also lacks an adjustable lever, so the
span may not suit everyone. Also, with the spares situation for
Skorpions being a bit uncertain, it's always useful to know of an
alternative part.
Caliper:
The caliper is a copy
of the Brembo P 30/34 unit used on lots of European bikes, plus
European built Yamahas, so is fairly readily available used on Ebay.
Look for calipers with a 40mm spacing of the mounting holes – later
ones are 63mm. One tip when buying one is to look for the smallest
and least common bike it was fitted to as prices are lower – a
caliper from a Cagiva 125 can sell for a half of what an identical
unit from a Ducati 916 will, so shop around. The caliper (and master
cylinder) I used were from a Cagiva Mito 125.
Basically, this is a
straight 'bolt on'. The hose connection is the same thread so you
could reuse your old hose. Both the Grimeca and Brembo calipers use a
pad pin retained with a circlip. I've never been very happy with this
arrangement, so have replaced it with a M6 nut and bolt.
You need to find a bolt long enough that the pads will slide on the unthreaded
portion, and cut the excess threaded part off. Fit with a pair of
washers and a nylon insert nut.
This is a common
modification used by racers and will pass the British MOT (annual
safety test). I think you have to drill through the inner hole to
enlarge it to 6mm (I can't remember now).
This diagram shows the
dimensions of the bolt
Despite what 'self
appointed experts' might tell you, there is no difference between
gold Brembo calipers and other colours. The calipers are just painted
(not anodised), so you can repaint them if they are a bit tatty or if
you just want another colour.
Master cylinder:
I had bought the master
cylinder and caliper as a pair, but any suitable master cylinder will
work. It doesn't have to be a Brembo, just as long as it has a 13mm
piston diameter (Brembo cast the size on the bottom). As the Mito
doesn't come with an adjustable lever, I fitted one from a Ducati
916. Again, the hose connection is the same thread, so you could use
your original hose.
I compared the span of
the levers between the Grimeca and Brembo master cylinders. Sorry the
pictures aren't very clear but they were taken in a cramped garage as
it was snowing outside!
Firstly, the standard
Grimeca has a fixed span of c.120mm.
The Brembo at minimum
is c. 105mm.
and maximum of c. 125mm
When I fitted my
caliper and master cylinder I had a new hose made and used some shiny
bolts, but you could reuse your existing parts.
In use the adjustable
span is good as you can 'fine tune' it to suit your hand, and the
setup has a better 'feel' that the Grimeca original, although it
could have started to get a bit worn.
If any one else does a
similar modification, please post details.
See my blog post on a similar change here - http://mike-thistledown.blogspot.co.uk/2011/06/hold-your-horses.html
ReplyDeleteI didn't change the levers or the master cylinder, just re-used the existing ones on the bike.
Nice 'how-to' article, Norman. I never could understand why the reach to clutch and brake levers on a lot of bikes seemed to be designed for 'Andre the Giant' .I don't have small hands, but usually went to dog-leg replacement levers. Then down at the shift lever/foot peg area it seemed it was designed for size 6 shoes! Makes you wonder how many of the designers ever rode their products. Wasn't it your brother that did a foot peg modification write up on one of his bikes?
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