The ignition system on your bike engine will have no effect on a headlight unless you're using the white wire to power it. I would suspect vibration or road shock is what is making your headlight flicker.Would this help with flicker head lights I having a problem with that there 90 lumen flashlights aluminum
and always look like powers being drained from them.
I'd have to see a picture of your headlight and how you have it mounted before I could offer a suggestion. It is possible to mount it in rubber but that might cause you as much problem as you already have. I'd check the connections in your 'flashlight'. Make sure everything is tight and the battery spring in strong enough to hold things together. Flashlights are not designed to withstand the vibration encountered on the handlebars of a motorized bicycle. You might be faced with finding another light source.you have any suggestions on how to fix this problem would think rubber help ?