Here's my 2 Cents...... I cut my WR450 throttle stop off 11mm. This left the length at .910". Yesterday I got the 2 YZ450 throttle stops I ordered a Month ago. They are....you guessed it! .910" overall length. Please note that the fine folks at Dirt Bike stated that 18mm was the magic number. IT IS NOT! Cut 11mm off your WR450 stop and save 10 bucks from Yamaha (They already got $6000 to $7000 of your hard earned bucks! Hope this helps- did I mention that .910 overall is the magic number?