Is the T.O.R.S. system still on the bike, ??? has anybody unpluged the tors trying to disable it. Sometimes on different year models when its unpluged the engine will run like your saying your is.
Have seen people mis match ignition parts from different year models (which wont work) & cause the engine to do like that.
If for some reason the carb was flooding while the engine is cut off, it could puddle gas in the crankcase & cause the engine to do like your saying.
The spark plug cap can cause it as well.
Neil
C-Leigh Racing Team
In memory of Caraleigh Pritchard
1979 - 1992
Team riders, 2017 Extreme Dirt Track
# 25 450R Honda, Chuckie Creech, Pro, Pro Am, Pro Am Unlimited class
# 25, 450R Honda, Andrea Creech, Womens class