Its in the for sale thread lol, £450 with an MOT or £400 without, only problem is it would cost me about £70 in juice and 4 1/2 hours on the road to get it up to yorkshire.
Its strange that your XT has had so many problems... i thought most Yams are pretty much bulletproof , if you broke your bike for major parts (forks, tank, exhaust system, swingarm, wheels, carb and those new clocks you put on) you could probably scrape back a monkey, but not having much experiance with those bikes i couldnt honestly tell you what its worth as it is, changing the engine would probably reduce the value slightly as it would no longer be matching frame/eng numbers and unless you really know what engine your putting in you may end up with the same problems all over again.
is the gearbox fault a common problem?, you may be able to screw some repairs out of Yamaha if its a known fault/recall