I put a tail light/brake light on my bumper a couple of weeks ago and the tail light keeps blowing(1157 bulb). I have the light grounded to my bumper and pluged the wires into the stock harness. The factory 3 light tail/brake light used 2 small outer bulbs(194) and one centre brake light bulb. Now I'm thinking that I need to put a resistor in line. Am I correct in thinking this or is there some other reason the bulbs don't last. The brake circuit works it's just the tail light that blows.

vibrations the issue , LED is your cure......

Less voltage via a ballast resistor my help but dont count on it.

I thought about the vibration thing too, I guess I'll have to get an LED light. What if I put a 1157 LED bulb in? Will that help, or should I get a full LED tail light?

LED 1157 would work but you will need to put a bridge rectifire in the power feed on both tail and brake lites.

Why?? I have an LED 1157 in my bike with no troubles.

LEd lamps need 12 volts DC your bike has a battery and charging system that is a DC system. Cant say for sure that the led 1157 didnt have it built in allready. I dont think it will hurt to try it.

I think I have it fixed! I basically rubber mounted the brake light. Have been out all weekend on rough trails and it's still working. I hope I have it cured.