huski

The letters A-G refer to the piston diameter and are microscopically different.The piston would be matched to the cylinder to obtain the correct clearance at the factory.Its not unknown for people to fit the next size up in a worn bore,but it's not the right thing to do.They don't all start out with an A piston

Kill button?

Neat job,as I'd expect from TRS,but is it necessary on a trials bike?

Well done,worth more at part x time too

On the basis that the brake worked(albeit poorly) before the master cylinder was worked on,Id be looking at the master cylinder.As above remove the brake hose from the master and see if fluid flows.I wonder if you've been given the wrong piston ,if you fit the old one does it flow fluid?Least now we're not working it gives you something to do

Can you use the syringe to push fluid through from the bleed nipple.Put a few turns of plumbers PTFE tape on the nipple threads first

Doe the fluid level in the master cylinder reduce?If not neither of the cylinders are leaking.Id be looking at the clutch itself,bet the clutch basket is notched and rough where the clutch plates contact it.The clutches on these used to drag when new,not as badly as yours is though.Steel plates might also be warped too.Look on the Montesa forums on here,bet there's loads of information

Does it start and run well with the expected power?Has the previous owner retarded the ignition timing to soften it and gone too far?

Thinking of getting a pair of Alpinestar tech T,is the sizing accurate?Anybody got any opinions about them,good or bad,thanks in advance

Wouldn't go for a bike that old,generally they're worn out and beyond economic rebuild even if free.All down to the maintenance it's had,if everything still works like it should and it's cheap it would get you started

Can you force a torx bit into it and pull it out?

Think you just remove the spring and put it back in a different set of holes.You don't need to drain the radiator,just remove the pump with the hoses still attached and tie it up out of the way.To remove the kickstart undo the bolt a couple of turns and sharply bring the kickstart round to the starting position,it tends to stick on the shaft

Check the connector where the stator plugs into the wiring loom,ensure all the connecting pins in there are not corroded

First time I've seen that.Maybe the previous owners hit big steps hard and /or big drop offs a lot

Red KTM

Studied the wiring diagram,you're right,must earth through the stator wiring

2018

Noticed the fan wasn't coming on,so thought I'd find a failed thermostat.Wasnt that so investigated further and had no power to it.Seperated the stator connecting plug to find it corroded and burnt out.Seems it's not very waterproof and has cost me a stator as the plug is unrepairable,Can't get any resistance readings from any of the terminals,though the bike still runs fine.Its in an exposed location and more vulnerable to jetwashing than I'd hoped .Well worth checking it regularly

You'd have to ride both to make the decision,don't think there's a huge difference

Not sure it would like being held flat out for a quarter mile anyway,really not what it's designed for

It's not easy to get the timing right,try doing it slower.When you can do it properly you don't need a lot of speed

Make sure you don't get wd40 on the brakes.Clean air filter and clean oil,it'll go forever in clubman hands.

It shouldn't slip with that thickness clutch pack,do you have some free play at the lever before it moves the master cylinder piston?ATF is the best oil to minimise clutch slip,try dextron 3 ,400 cc and see if it improves.Might not do it straight away,but you should see an improvement after about an hours riding

Is it down to water getting in the connector plug and shorting out perhaps.Some owners getting over keen with the jet washer maybe?

It is 258cc,it was called a 280 for some reason