wr450 woodruff key info

Could not go ride my new bike with a clear mind with all of the posts of breaking woodruff keys. I have been watching all the posts for a couple of weeks now and based on my findings I believe that slomo138 is on to the possible cause of the whole problem. I laid my bike on a 45 degree angle so oil would not be lost and removed cover (see page 4-77 of service manual), removed flywheel nut. (You can use a 15/16 open end wrench to hold fly wheel once cover is removed - you must hold it at an angle but it works). I did not have the factory fly wheel puller, so I used a puller similar to a steering wheel puller. I removed two of the five 5mm head allen bolts that are located on the inner portion of the fly wheel. I used two long 6mm x 1.00 bolts approx 2 1/2 inches. I tightened puller with some tension and gave the puller a hit with a brass hammer and the flywheel popped off. Cleaned taper part of crank and taper on flywheel with contact cleaner. Did not have spotting dye as slomo138 had suggested so I took a large black felt marker and marked the whole taper portion on the crank end. (Remove woodruff key) Took fly wheel and installed onto crank shaft, pushed and turned back and forth 360 degrees 3-4 times. Total contact patch of taper is approx 31mm in length. My pattern from felt marker indicated something much less. From the smaller end of the taper contact started 2.5mm in and was 6mm wide and on the larger end there was a very small contacted patch approx 1mm. (repeated process twice for kicks and giggles and found same result). Next step took valve lapping compound and applied to taper on crank, installed flywheel turned back and forth while pushing 5-8 times. Cleaned away compound and repeated felt marker test. Found that contact pattern and increased to 18mm the larger dia. portion of taper was still not showing contact. Repeated process with valve lapping compound two more times and then the last time when went to check pattern all felt marker was rubbed away and you could feel fly wheel binding when turning back and forth. Installed flywheel and torqued to 47ft-lbs as correction sheet in service manual indicates. (You can use that 15-16 end wrench to hold flywheel). Reinstalled cover and it’s ready to ride. Good luck - I hope this resolves this once and for all.


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