Thanks for this advice guys. I've had to fix the carb now, as I accidentally broke off the valve's rocker arm where it connects to the throttle cable. I'm trying to make a new arm, but my improvised arm is rather dodgy.
There was a lot of rust flakes and gunk in the fuel tank, and it seems the carb was getting fuel, but not fast enough. There also does seem to be a fair bit of gunk clogging up the carb where it joins to the piston chamber.
Once I get the throttle arm, I will try it again. Bodywork needs very little. The model I have seems to be non-existent. It needs a sand and new paint, and there is a slight chunk out of the body near the front where a stone has been thrown.
