I have done a lot of research already before I knew absolutely nothing!!
Basically from everything I have read you can get 1.3mm, 1.4mm, 1.5mm, 1.6m, 1.8mm spacers. Your meant to use combination to hit the optimal 9.75mm - 9.85mm total width. The thicker the pack the harder the clutch lever will be.
The reason I posted was because by my basic maths no combination of spacers i.e. 1.3mm x 2 will give me that measurement - hence my confusion!
Apologies if anything I say is daft I don't have huge amount of mechanical experience so bear with me!
I had the clutch replaced on my 2012 Pro Racing 280 a few months back. Since the new install the clutch lever is really stiff to the point where I'm getting really fatigued after short period of riding. Actual engagement and bite is great no slip at all and perfect for short run up stuff.
I took the clutch out and measured the following:
Plate 1: 1.4mm
Plate 2: 1.5mm
Total width: 10.21mm
I understand it should be 9.75 - 9.80?
I'm also aware I can get 1.3mm plates but that only brings me down to 10mm.
Basically I'm after a lighter clutch so I can ride through sections without getting hand / arm pump on clutch side! I do want to be able to do fairly aggressive short run up stuff though so maybe 10mm will be correct balance? Fitness isn't an issue I ride a lot and never have an issue on any other bike.
Sounds like you have air in the system,might be worth replacing the seals in the slave cylinder inside the clutch casing and bleed it again using the right mineral oil.
Hi mate is that in respect of the stiff clutch lever or the problems when cold?
Congratulations, you have a Beta I'm not familiar with GasGas clutches but this is an old problem with Betas and the fix is pinned at the top of the Beta forum. Don't be afraid, just tell them I sent you.
Nice one thanks Dan much appreciated.
Looks like a fairly big job but I'll give it a go!
I have a strange problem with my 2012 Gas Gas TXT 280. The first time I engage first gear after starting / warming the bike up the clutch engages immediately sending the bike lurching forward. No matter what I do with the clutch lever it stays engaged for say 10 - 15 seconds then it will start working and the clutch disengages drive. Obviously its a bit of a nightmare as not being able to stop is a bit sketchy! After the first time the clutch is faultless for the rest of the ride. I use Putoline Light Gear Oil if that helps at all.
This happened ever since I had the plates replaced.
I've just had another workshop look at it and they did the clutch master cylinder seal kit (which made the clutch lever much harder to pull in) and bled the thing. The reckoned they had sorted the issue described above but unfortunately they haven't.
Before I take it back in just thought I'd see if you guys had any ideas what it might be or whether your bikes have ever suffered the same issue?
I would call that a roll up. If you used a double blip, you could go up much slower and controlled and come to a complete stop at the top. What you did is perfect for endurocross.
Fair enough In mtb trials its called a touch hop. I don't think I'd have a hope with a double blip on that height of rock. It was a flat run in with no kicker so the front touch definitely helped I think I'll give it a go with back wheel first next time.
wow, looking good judging by your avatar you've got a trials bicycle background?
Thanks mate Yes ridden mtb trials for over 12 years but last 5 years been concentrating on DH. Rode MX for quite few years when younger which helps a lot too. Just loving learning a new discipline, got the same excited school kid feeling when first started riding trials learning new stuff every time I go out.
Nice, but that technically that is not a splatter. Back wheel hitting the object first is a splatter.
Bugger! What's that technique actually called? Is there any disadvantage of using the front wheel bounce?
Any comments / technique tips more than welcome. I love filming in the 120fps mode on the GoPro3, great for seeing where things are going right or wrong.
I repacked the silencer (right old game!) and it is definitely a bit quieter but still pops the same. If anything I packed it too tight but difficult to tell.
I'm running 60:1 fuel / oil mix which I know is considered to be a bit overkill. Not sure if this could cause it? Next tank will be nearer 70:1.
If anyone has the settings I'd like to check it anyway to make sure my bike is setup correctly.
Been browsing an auction site earlier and noticed there's a rear formula caliper on there cheap from a 2012.
Thanks for the heads up Steve.
Four pots have been done before. Most brakes work fine from the factory. You bought a bike which the brakes worked poorly. On the other hand trials bikes are a very small market, and most riders are by nature cheap! Good luck on the rebuild. Just for your info when the Formula brakes came out, most riders swapped the brakes off the old bike. Some did that several years in a row!
Point taken.It was my mistake for assuming the 'uprated' brakes on the pro version would be better than standard - lesson learnt do proper research
Just a quick update:
Rather than doing a full rebuild straight away I thought I'd try to bleed the brakes first.
Post bleed rear brake is absolutely spot on. Really nice lever feel with loads of power. Time will tell how long it will last but for now I'm really pleased with the result.
All the back wheel stuff is making a lot more sense now
Thanks again for everyone's help and apologies for my simple questions - I'll post back if it all goes belly up!
This is a useful thread to a new member like me. I have a Gas Gas TXT 321. Thought I would be clever and do some preventive work, including replacing the thermo switch for a new one. Why or why did I not leave well alone as the bike was running beautifully.
The new switch shot out when the engine warmed up. Okay I thought, maybe there is something wrong with the new thermostat. Solution: Put the old inline one back in, replace coolant and away to go....except it blew this one out too! Where am I going wrong? Anyone know the installation sequence for the thermoswitch as maybe I'm getting that wrong. Could it be air in the system? And would it be disastrous to by pass the switch altogether by hardwiring the two spades together and leave the fan run all the time?
Am going to do another trial soon and really need to sort it out...Arrggghhhh!
Hi Gareth
Unless I'm being really simple (quite possible) the system shouldnt be under pressure as there's a overflow pipe. So there shouldn't really be any pressure certainly not enough to blow the thermo switch out of the rad.
First thing I'd check is that the overflow pipe isnt blocked.
In regards to hard wiring the fan as per above the disadvantages seem to be excessive wear on the fan and the engine may not reach optimum running temp. However for one trial it wouldn't hurt.
The formula brakes can be made to work well and reliability. From new they had 2 initial problems.
Machining swarf was left in the fine passages
Some of the edges and ports that the seals moved over had sharp edges / burrs
One or both of the above then wreck the seals or jams the pistons.
Thorough clean out, polish and deburr and they should be OK
Ok thanks I'll give it a try and see if it does the trick.
I do find it strange that there don't seem to be any aftermarket options for brakes for any trials bikes. Surely if someone designed a decent four pot setup for the rear with a bigger disc that really worked and was reliable people would pay the extra, I know I would.
Anyway thanks for the info, any further advice much appreciated.
Does anyone have recommended settings for the Keihin carb? 2012 280 Pro Racing.
Bike runs pretty sweet but on tickover the exhaust 'pops' quite a bit - more so than others I've listened to on Youtube. I'd like to check the mixture is as per recommended.
I've searched everywhere and cant find anything - sorry if I'm missing the obvious.
I think I've buggered up my rear brake. Having busted my hand in a big DH crash a few weeks back I've occupied my evenings working on the gasser however a little knowledge is a dangerous thing and all that. Completely new to all this so bear with me.
My rear brake hasn't been very powerful since I bought the bike few months ago. I tried the getting it hot then putting water on it which worked a treat for a very short period giving a nice sharp confidence inspiring bite but then shortly after it went back to the way it was before.
Ordered some Galfer pads which I hoped would do the trick.
I took the rear wheel off, had a look at the caliper and it all looked pretty manky in there. So went about trying to give the pistons / caliper a quick clean using brake cleaner. To do this with the old pads out I pumped the rear brake lever to work the pistons out as far as I'd dare. Clean them then push them back in again - repeating this process about 5 times.
All looking nice and clean, new pads in, wheel back on job done.
Only problem is now the rear brake pedal goes down in two stages with a nice crunching noise. No power in the rear brake at all until right at the bottom where it just about locks the rear wheel. For what its worth the pads do feel like they will bite much better if everything was working properly!
Three questions really:
What did I do wrong?
What has happened?
Cost considerations aside what is the best rear brake I can get for my bike without major modification?
Coming from mountain bike trials I do really want a really good powerful rear brake and Formula don't seem to be regarded as being very good from what I have read.
Like I said go easy on me I'm new to working on brakes in general, mtb disc brakes are very much fit and forget.
I was just about to ask if there's actually any disadvantage / reason why I don't just hard wire it and have the fan running all the time? I'd rather have it on all the time than wondering whether it should be coming on!
I'm trying to remove the thermostat to replace as I'm still not confident the fan is working as it should but am having difficulty.
Top right of radiator - I've removed the cir-clip holding the thermostat in. I've tried pouring hot water down the gaps to help free up the o-ring. Still the thing will not budge. I wanted to check on here first before I give it too much just in case there was any tips / technique to removing.
I what you said jfc and made sure the coolant was at the correct level. Went for a last night for a good 1hr 1/2, absolutely no problems at all with the fan working as it should
Thanks again for all your help very much appreciated.
I'm not familiar with GasGas clutches but this is an old problem with Betas and the fix is pinned at the top of the Beta forum. Don't be afraid, just tell them I sent you. 
In mtb trials its called a touch hop. I don't think I'd have a hope with a double blip on that height of rock. It was a flat run in with no kicker so the front touch definitely helped I think 
judging by your avatar you've got a trials bicycle background? 
Txt Pro 2012 Clutch Pack Measurement?
in Gas Gas
Posted
Cheers guys.
I have done a lot of research already before I knew absolutely nothing!!
Basically from everything I have read you can get 1.3mm, 1.4mm, 1.5mm, 1.6m, 1.8mm spacers. Your meant to use combination to hit the optimal 9.75mm - 9.85mm total width. The thicker the pack the harder the clutch lever will be.
The reason I posted was because by my basic maths no combination of spacers i.e. 1.3mm x 2 will give me that measurement - hence my confusion!
Any further advice would be great.
Cheers
James