On Wednesday, June 29th, 2022 I was riding my new Kawasaki KLX230S on private property. While riding I was experiencing surging while riding off-road. We set up a course to practice for my on-road license test and upon returning from the opposite end of the course I applied both the front and rear brakes bringing the bike to a stop. At that very moment the motorcycle accelerated to full throttle on it's own causing me to dump the bike rather than run over my husband. A Kawasaki dealer told us we probably overfilled the fuel tank and got fuel into the evaporative control system, we had not: or, that we tipped the bike over getting fuel into the evaporative control system, which we had not done until the unintended acceleration. At the recommendation of the dealer my husband took the bike on a very long ride, to clear out the evap control system, and the surging calmed down and we didn't experience any further unintended acceleration. However, the surging returned; this time only while going downhill. While on a ride the check engine light came on and we took the bike to Kawasaki dealer. The dealer told us the code was for the Vehicle Speed Sensor but the sensor checked good so after much troubleshooting they decided to replace the Main Engine Harness. Upon receiving the bike back my husband took it for a test ride and while it idles correctly it still surges going downhill; so bad in fact that it is dangerous and unridable off-road going downhill. The dealer claims that