Cam Timing Belt change - making it easy

[WTSDS]

I found this little homemade item very helpful with my first Monster cam belt change.

Thought of it after spending time mounting a degree wheel onto the crankshaft, that's when it dawned that the central pulley is 1:2 with the crankshaft and the cam pulleys same size as the central, i.e. 1:1

It's a  6.5 cm, 2.5 inch diameter bit of cereal box cardboard, with markings from a school protractor at 0 and 135 degrees.

O is Horizontal TDC, 135 is Vertical TDC representing 270 degrees of crank rotation. It's held on the shaft of the pulley with a magnet   

Yes, you can just make the same markings on the central pulley, but it's easy to get bamboozled with TDCs when you are hauling the motor over with the rear wheel, working out where each piston is going, which is on compression or exhaust while trying to eyeball the pulley markings. And it saved having to go around the other side of the damm 'bike to eyeball and decipher the sightglass markings every few minutes. 



The next pic shows the Vertical cam pulley lined up with motor at TDC for Horizontal cyl. The pencil marking on the camshaft nut lines up with the reference knob when Vert  piston is at TDC. This mark, and the disc, allows the belt tensioning of Vert cylinder to be done without any doubt that the valve mechanism is tugging on the belt

Thought I'd share.......