Hi, :~
Check that the actual shaft diameter of your new motor is the same as your old one. The Heng Long motors are 2.3MM in diameter and so are some of the more powerful motors such as the 'Graupner 400' which is a good motor £6.49 each from
http://www.cornwallmodelboats.co.uk/aca ... otors.html" onclick="window.open(this.href);return false;
I went up to a Graupner 480 and this motor has a 3.17MM shaft which was harder to get a pinion for.
Regarding removing of the old pinion...it is relatively easy without destroying the old motor....If you have a small vice then position it so that the pinion is above the jaws and the motor is suspended in the 'Air' the drive shaft can the gently be taped with a small hammer until the end of the shaft is flush with the pinion. Then use a drift that is say 2MM in diameter and gently tap the shaft out of the pinion. The pinion can then be fitted onto the new motor by resting the base of the new shaft on a piece of aluminium on a steel surface. The pinion can then be taped onto the drive end of the new motor until it is flush then use say a very small socket or a steel tube to knock the pinion down to the correct position.
It may be easier to simply buy new pinions that have a grub-screw so that you can simply attach the gear with a small allen key which will save all the bother in the future. Just make sure that they are 48 Pitch Teeth or they will NOT work correctly with Heng Long or Tamiya gears.
Alb.