AlexW wrote on 07/12/17 at 14:55:25:Maybe a 2-stroke slows down more quickly than a 4-stroke when you kill it?
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Back when 2-strokes ruled the roost, most serious races would set their bikes up so they wouldn't idle at all for two main reasons. One of those reasons was to get more responsive bottom end power. The other is increased engine braking when you cut the throttle going into a corner. The goal is to keep the rear wheel turning the engine over until you cracked the throttle to lite the engine up again. But once in awhile the rear wheel would lock up and skidd instead of restarting the motor if you weren't careful. This low idle meant that you almost never touched the kill switch. It's main purpose was to kill a bike if the throttle was stuck open after a crash.
Modern 4-stroke off-road bikes have more braking power than two strokes and run an idle.