I've got a 2003 WR450F that was running badly when I picked it up last week. The engine won't rev beyond mid-range. It feels like something is holding it back badly. At low to medium revs it feels great and pulls hard. I've changed the spark plug and checked all the connections. The air filter is clean and I've tried running without the airbox side cover fitted. I haven't stripped the carb down yet because, if I remember right, you have to remove the rear suspension etc, it sounds like a balls-ache. I'm getting a good voltage at the battery when the engine is running. I checked the voltage at the TPS plug with the engine idling and the plug disconnected but it only showed around 1v. The manual says it should be between 4v and 6v. It says to replace the CDI if the voltage is out or scope. Does it sound like CDI is the fault? I thought the engine would run OK with the TPS disconnected if that was actually the problem? Any suggestions what else to check before wasting more money on a CDI? I guess you're all gonna tell me to strip and clean the carb first, right? Anyway, thanks for any ideas you might have.