1974 XS/TX650 rebuild

[th62]

First order of business was to tear the bike apart and look at the damage. In their wisdom, the Japanese decided to build the bike so the motor had to be removed from the frame to work on it, and a heavy lump of metal this thing is. The motor can only be removed by laying the bike on tnhe right side, undoing all the mounts and jiggling the motor back and forth while trying to get the motor free.

The TX is an odd mixture of over engineering and under engineering, some good ideas and some terrible ideas, as I was to find out. OtHer damage was the drive chain, despite being way beyond it's life span, it had been left in service so both sprockets had badly hooked, teeth. The previous owner had fashioned a rough auto advance plate which was at least 90 degrees out. The motor would never have fired up anyway as compression was down around 70/90lbs. Carbs were choked up, valve seats were pitted, starter gear spring had lost all tension, cam chain was stretched so much that the motor couldn't be timed, even with a whopping .30mm points gap and both cam chain guides had lost their linings.

Other visible damage was to the upper crankcase and numerous gouges in the side covers which would have to be ground out. I located a set of second hand crankcases, so sent off for them and also sent off for a seal kit, a gasket set, two new cam chain guides, a new cam chain, an auto advance unit, some shifter drum pins, valve spring seats, some stainless allen head fasteners, new pistons, rings, gudgeons and a few other little bits and pieces. I also sent the barrel off for reboring and the head off to have the valve seats reground.

Whilst waiting for the parts to arrive, I stripped the rest of the bike down, throwing out all the fasteners, spokes, seat pan, battery carrier, spokes and a lot of other bits and pieces that were just to rusted to be re used, then set about bringing the alloy back to life, a hard dirty job!