GavinH

JK: see my original reply - the replacement seals in the link did not fit, I reused the old ones. Dan: You could well be right about the silica, the stuff I scraped out looks like the white gunk that builds up in the bottom chamber of a stovetop coffee pot if it isn't used for a while. I just assumed it was corroded alloy.

Hello JK, I bought these https://www.ebay.co.uk/itm/306807336648 and they don't fit 😁. I solved the problem by doing what I used to do on my 1980s/1990s commuter bikes... The problem is caused by corrosion inside the grooves that the seal sits in - the corroded alloy increases in volume and forces the seal tighter against the piston until eventually it is so tight that the piston can't retract when the pedal pressure is released. I took the caliper off, drained the fluid, popped the pistons out with a foot pump, and carefully prised the old seals out. It's then just a case of carefully scraping the corrosion out of the grooves - I used a right-angled dental pick which ended up in my toolbox years ago (I have no idea why!) but in the past I've also used a pop rivet shaft with a 90° bend at the end. The corroded alloy also 'grows' into the back of the seals so you need to scrape that off with your thumb nail. I then put a drop of ACF50 into the grooves before refitting the seals and piston, reconnecting the hoses and bleeding the system. The caliper has worked perfectly for the last couple of months and I only ever had to do it once on my old Yamaha commuter bikes, which I kept for many years after doing this fix. I was initially cautious about the ACF50 contaminating the brake fluid but I never experienced any problems. It takes me a few hours but it seems to be a permanent fix. I hope this helps.

Scrub that, I just found some on FleaBay 🙂

I got the bike out yesterday after not using it at all last year and it was generally fine but the rear brake was binding a bit so I decided to overhaul it and replace the seals. It appears that Beta only do a kit which includes new pistons, which I don't need - has anyone found an aftermarket supplier for the seals only?

I haven't put it on the scales but I have the impression that the weight distribution of my 2013 EVO 300 is biased towards the rear. Sag and spring rates (stock on the front, uprated on the rear) seem good but I need to push down about a foot in front of the lowest point of the frame to get the front and rear suspension working together. I'm tempted to drop the fork through the yokes by a few mm to put more weight on the front but, being a total novice I don't know if a bias towards the rear is considered a bad thing? Any thoughts?

Yes, thanks - I caught that having just serviced the linkage whilst replacing the spring. I've been sitting typing the values into a spread sheet whilst watching TV. PDF attached... 2010-2014 Beta EVO Torque Values.pdf

Brilliant! Thanks very much for taking the time to post this, I really appreciate it. Gavin

Ok... I fitted the stiffer springs from Beta UK yesterday (80Nm front, 'K8' rear) and refilled the fork with 5w oil - the old fluid that came out was literally the consistency of custard! If anyone is interested, for my suited-and-booted 14 stone, this setup gives 55mm front sag with zero preload, and 60mm rear sag with the adjuster about 10mm out from full in. Totty69 -the only torque info that Beta UK had was the table for engine and engine-to-frame fasteners so if you have more than that and can post a scan/photo I'd be very grateful. In the absence of any other info I torqued the axle and caliper bolts to a bit more than I would on my mountain bike 😄

Thanks, that's very helpful. I'll try Lampkin's tomorrow and get back to you if they can't help.

Thanks, that sounds like exactly what I was looking for. Hopefully someone will post a link or pdf.

Hello, I'm new to Trials Central and this is my first post... I decided to have a go at trials, bought a 2013 EVO 300 2T and have downloaded all the manuals and info I could find. I spent a couple of seasons club racing short circuits and built my own 750 Yamahas, so I'm reasonably confident on the tools but specs/settings supplied by Beta seem a bit sketchy compared to what I'm used to from Yamaha. I'm about 14 stone suited and booted and have bought a pair of 10% uprated springs to fit. For the fork, the owners manual says "Note : For screw A (triple tree clamps): torque wrench setting 7,8 : 9,1 Nm" but gives no torque info for the caps or anything else; I'm guessing 7.8Nm is the lower yoke and 9.1Nm the upper one? Is there a document or manual anywhere with more torque setting info? The Beta is built a lot lighter than what I'm used to and I don't want to strip any threads. Thanks, Gavin