I stripped the CEN down for a clean and all round check up and when I put it back together I noticed a strange movement whilst checking the brake setup. The throttle opens up fully no problem but when the brake is applied the whole back end and the engine appear to move! Its as if the truck is trying to fold itself in half!! I have loosened the brake spring so there is play before contact and none of the rear end screws are loose so what is the problem? Anyone got any ideas?