Take the head off and put a dial gauge on the piston and find TDC. Then back it up the 2.6 or what ever it is millimetres before TDC and put marks on the flywheel and sidecover. Then its hit and miss as far as I know with getting the timing with a light right. If someone kicks while you watch the light , I think you might be able to work it out. With the twin pipe we had to cut new slots as it was a fair bit past the original adjustment slots. You wont get it right till it starts. I have memories of pushing mine and turning the stator plate around till it fired. Then its a point and shoot. Again, don't think you are limited to the slots as you may be way out and have to make new slots.