If the freedom of speech is taken away then dumb and silent we may be led, like sheep to the slaughter.

- George Washington

Saturday, 6 February 2010

Mechanical therapy

As a nice, restful activity to take my mind of my other troubles (see recent posts, passim), I decided to overhaul the front brake of the Yamahaha. Don't ask me why. It seemed like a good idea at the time.

The Yam's front brake was always very good. The front suspension is obviously long-travel and very boingy, but the front stopper was always able to bottom the forks, pin the front tyre to the tarmac, and haul the XT up in very short order. Until one day I decided to inspect it.

Bad move.

The pads were worn into a wedge shape, and it was hard to believe that they were doing anything at all. The brake has two pistons, and one was very sticky, so the non-sticky piston was doing all the work and wearing the pads at one end only. One end was down to a razor edge. The other was almost new. It looked horrendous, but it worked really well.

So I bought some new pads off eBay, and took the caliper off to clean and free up the sticky piston and put in the new pads. Once I had assured myself that the pistons were moving freely and the new pads were in place, I took it for a test ride. The front brake was no more than moderately good, even with both pistons working in harmony. I reasoned that this was because they needed time to bed in, so I left it for a while.

Commuting over several weeks taught me that they weren't going to get any better, and in fact the pistons were getting sticky again, so I bought an overhaul kit. Last weekend, I planned to strip the whole caliper down, and put in new seals and rubbers along with fresh fluid. The caliper came off OK, but I couldn't get one of the little pins that keep the pads in place out of its thread. The hexagon socket in the head of the pin had rounded out, and (in order of desperation) a big screwdriver, a bigger Allen key and hammer, and a stud extractor all failed to budge it a millimetre. This means that I could not dismantle the caliper, or fit any of the new seals.

I now need a new caliper (or rather, a decent second-hand one that I can use the overhaul kit on), which is going to be a little more expensive that I had hoped. I cleaned it all up and put it back together today. I had a good look at the pistons, and they are getting rather corroded, which explains the sticky operation. A short test ride confirmed that they were indeed better than before (always a plus, I find), so the time wasn't completely wasted.

One conclusion: GoldFren HH brake pads are rubbish, and original Yamaha ones are good. I need new pads for the Honda, and this will guide my purchasing decision.

A light bike like the XT, that weighs about 160Kg and does a maximum of 70 mph (and has such good engine braking that the front and rear brakes are almost optional extras) is one thing.

A 300Kg behemoth that may* need to be brought down from 140 mph is a different kettle of piscatorial entities, and will be treated to Honda pads, however much they cost.

*I said may. Not under my stewardship, obviously.


  1. ...well you might be riding the 0.3T behemoth in Germany on unrestricted roads at 140mph?

  2. Hehe - true. I did a fair few miles at 120 on the autobahn last year, but fully loaded with camping gear at 140 was more than my nerves would allow. I'm getting too old - or my imagination is too good.


Comment is free, according to C P Scott, so go for it. Word verification is turned off for the time being. Play nicely.

Related Posts Plugin for WordPress, Blogger...