: 8) gidday all. as with regard to sticky power valves ( only if its a mechanical freeze up, not electrical) it is possible to free up the valve by removing only the expansion chamber & rc cover. elevate the bike at an angle of about 30 deg ( rear end up) so as not to get any foreign material & liquids into the cylinder. remove valve actuator arm & cables. remove seal retainer & seal. position piston in t.d.c possition & sparingly use small amounts of carby cleaner to soften the carbon deposits around the valve shaft. into the exhaust port, (around the shaft both sides) spray an oil based lubricant & also where the shaft protrudes from the rc housing. persistance is the key as you work the shaft in it's full travel. beleive me , it's a lot easier to do it this way than remove the top end( it only took about 25 minutes & this i thought was'nt too bad considering it was frozen almost solid). hope this helps fellas.
cheers rikkster.