Hi all,
dear Patrick, first of all, welcome here.
I am a little bit confused about the failure description that the seller/former owner of the bike gave you. If the electric starter motor
tried to engage during a highway ride, this would cause some horrible noises and a lot of broken parts. But this is nearly impossible: Even if the starter mechanism is faulty (which is quite common unfortunately in TR1 bikes), an
engaging of the starter should not take place as soon as the combustion engine is running.
During the starting process, the electric starter motor turns over the combustion engine. But as soon as the combustion engine starts running, its rotation speed becomes higher than the speed given by the electric starter system. Therefore, the rotating combustion engine will "overtake" the start mechanism. Three components are responsible for a correct "overtaking process":
- the starter freewheel, shown as figure (2) in Anja's coloured picture
- the mechanical lever, fig. (9)
- the starter solenoid, fig. (10).
The regular function of the
freewheel is that it runs free (smooth and easy) in
one turning direction, but blocks the rotation immediately in the
opposite turning direction. You can test it by rotating it by hand: If there are any doubts (not turning easily in one direction or not blocking correctly), it will be better to install a new freewheel. (They are available as after market parts in online auctions.)
A typical failure of the
lever mechanism is that the grease all around the pivot axis has become old. Therefore the lever is not moving easily any more, but gets "stuck". Cleaning and some new grease will help you out.
And a common failure of the
starter solenoid can be that, due to wear and tear, it doesn't switch quickly, strongly and easily, but moves slowly, producing not enough pulling power any more. Installing a new solenoid will help. (Yamaha XV 1100 parts fill fit, too. And after market parts as well.)
Shortly ago, I have reactivated an old TR1 wreck which had been sitting for 17 years before. When pushing the start button for the first time, I heard some loud clicking only. (Which meant that the starter solenoid tried to pull the lever, but wasn't successful at first.) Therefore I gave the mechanism some push moves (back and forth with a wooden stick, e. g. the grip of a screwdriver). After some of those moves, the mechanism "woke up" and became strong and easy enough to pull the lever completely (and therefore turn the engine over correctly).
Good luck with your project - sooner or later, you will get it running...!
Cheers,
Roland