Baron You posted a problem then told us all you'd fixed it, as for the post about your bore i nearly answerd it yesterday but had to get some kip, I start work at 3. But as far as it goes a 175 piston may fit but you will need to measure up carefully as you obviously have a 175 big bore on that bike.
Right streaky sorry about that i have a thing about high horses.
If you could post the wires that you have at the cdi we can probably work it through, Yamaha are as reluctant to spend as anybody else so if it works they leave well alone and back when your bike was a lad looks were all important so as the loom is not important to the look of the bike it is more than likely a quick upgrade on the old stuff.