Well I did up my WR250 cosmetically and a couple of issues internally in the engine and now it won't rev out. Previously to the work the engine performed really strong except I was getting water in the gearbox. Externally I changed the chamber from an gnarly to a stocker I got off ebay for a 2006 engine. Internally I had a replace the waterpump seal and had a little help from a friend with a 360. Unfortunately he jumped the gun a little and started removing the left cover assembly as he was under the impression he needed to install the waterpump seal from the other side. To do this he took the left power valve cover and pulled the ball joint off the lever and counter shaft. After trying for a while to release the cover we realised it didn't need to come off we bolted the cover back up and replaced the seal from the outside. Then we bolted everything back up. To our knowledge nothing had chenged in terms of the counter shaft from the governor to the power valve. Everything went back together easily Now when I rev the bike it revs kinda slow and then stops about half thru the usual revs band. About same engine speed everytime it stutters and won't rev out. Riding it and the low end is fine but it doesn't transition to the peaky band it used to have. Just bogs. I've replaced the fuel with fresh, checked the plug. Am I looking in the right place? Also if theleft cover is going to have to come off why does it come most of the way and then just stop?