Just did a cursory online search, and the two most recent stories of motor cop bikes bursting into flames after impacting a vehicle involved a
Harley and a
Honda. You'd prolly need to use LexisNexis to find other instances of exploding bikes.
According to some witnesses in this
local tv news story, the fire from Officer Roberts' blazing bike reached traffic signal height. Motorists and passersby used their jackets to help smother the flames on him. Even his boots were on fire. The current Fresno Bee story includes a photo of the destroyed-to-a-crisp bike. I like how he was quoted as saying he wanted to return to motors after his recuperation.