Starting is a problem uses 1 plug every week and backfires

Your engine seems to be "flooding". Check operation of choke, ensure it's not remaining on. The air cleaner may be clogged, replace if suspect. Refer to owner's manual (or local dealer's data) for correct sparkplug range applicable. Check condition of the plug lead caps, ensure good contact with plug. Carburetor pilot and main jets may be worn or damaged, try one size lower. Take sparkplug out and turn engine over with kickstarter till engine is Top Dead Centre (see timing mark on magneto) poke your finger in plughole for a good seal and turn motor over till suction is felt on finger, hold there to guage compression of engine. It should **** air in when you take your finger off even after 10 seconds. If bad response, a Top end service may be required to get valves doing their best, good time to check clearances and condition of piston/rings.
Cheers.

You have to find a hotter plug or try and lower the voltage of your bike, which is next to impossible. But it can be done. the old cars had a voltage reducer on the coils, and when the car wouldn't start, you just jumped the wire on the reducer and off you went with a ton of power, unfortunately, the coil couldn't take the heat and would die in about 20 mins anyway. But the plugs, I had to switch to autolite on my bike , they work 10 times better than champions, NGK are about the best, and they have a good heat range.Check them out.