crf100

im going to be rebuilding a friend of mines 2006 crf100 top end tomorow(changing the piston,rings,pin,circlips) and i have done this on my xr70 and my friends xr70 loads of times and i see that the engine is verticle rather than horizontal and i cant really figure out where the cam sproket on this bike would be i havent took the bike apart yet and i have found the instructions on doing the project but i wanted to know where the cam sproket it is located, because unlike on my bike it cant be seen with the head on the bike, as far as i can see