Well its kinda of a long story... i bought the quad off of my brother... origanally was a 250x but he converted it over to a 300ex. Made it 2 miles down the road with the 300 motor and locked it up... He then had the 250 rebuilt by a Honda dealership and converted the wiring harness back to a 250. They seemed to have forgot to install some electrical switchs... I get spark with the wheeler when i kick it over, also fires but don't get any spark at all if I try to pull start it. I have some hours on it now trying to figure out all the bugs. Personally don't like the harness on there now and think maybe my problem would go away if I had a hole harness... For all i know i could be missing parts from the harness. Correct me if I am wrong but the 350x 3 wheeler harness will work? 250x harness will work just fine for a 350x motor...????