250-500cc primary nut!!

[K5PL5]

Might be a repeat of an old post but i thought Id throw this out there...
I was riding my 2012 WR300 a few weeks ago and heard a weird scraping sound in the motor. Sounded like a noise inside one of the engine covers. No problems with the bike running. Ran strong and I heard nothing constant. No top end noise, not bottom end noise that I could decipher as "bad news". The noise was so infrequent that I was a bit stumped. With less than 4 hours on the motor I heard the noise probably 4 or 5 times total and it never lasted more than 2 seconds.
I read on this forum about the kicker shaft nut backing off and thought maybe that was the issue. I changed my trans oil 2 times since purchasing the bike. Total time on the motor at 2nd trans oil change was 3.8 hours. Too much metal in the oil and on my drain magnet for me to be comfortable with. Decided to take it to my local dealer, Toytech. I stopped in after work yesterday and was relieved to see that Chris, the tech, had found the issue. He actually saw the problem before he even cracked open the motor. The primary nut was missing on the shaft! He could see it thru the oil filler hole with a flashlight. The nut dropped in the bottom of the primary cover and was bouncing around in there like a nickel in a clothes dryer! It is chewed all to hell and did a number on the fins on my clutch basket as well. All the gears and bearings look great-I checked them out while the bike was still on the lift. He is going to clean the motor out thoroughly and replace my primary nut and clutch basket and possibly one or two other items after thorough inspection. He has seen this happen one time before on a 2007 WR250 so it doesnt sound like a real quality control thing or something that would warrant every WR owner checking it, but me being a stickler for preventative maintenance...well I'd be checkin it out!!
Some blue loctite and a proper torque spec and this should never be an issue for me again. I'm just glad we found it early enough that it didnt grenade my motor.
Just thought I'd put that info out in case any other owners hear that strange scrape sound I did

 

[marcmo0]

Oh shit! That is ugly. My clutch makes a racket like you wouldn't believe. Took it all apart, new plates and springs and hub. Put it all back together and BAM...still loud as hell Only way it goes away is if I pull in clutch lever.
I will double check everything now that I see your pic. Good luck.

 

[Brian Scott]

Nice catch and thanks for the cautionary tale.

 

[andrewgore]

Same thing happened to me (on my 2006 WR250), as noted in a post I had on here. Left me stranded on the trail 30 miles from camp:

I was blaming myself, until I realized that my manual does NOT spec loc-tite on the primary output nut. I said screw it & Opted for Red Loc-Tite when I fixed everything. Thankfully that trip only resulted in a torn gasket & a sheered keyway.

Andrew

PS - When I did the 6-speed swap on my bike, I put a LOT more loc-tite on things than spec'd by the manual. Rather safe than sorry.

 

[K5PL5]

Chris wrapped the bike up quick! New clutch basket, primary nut, water pump seal, new idler gear, and some bearings. Blue loctite on the primary nut too. Out of warranty by a few days but Husky/BMW still covered it. Unfortunately, Scott had to eat the labor cost. I should rephrase that....Scott chose to eat the labor cost. Just chargin me for fluids.
Hopefully she's good to go now. I feel confident knowing that Chris worked on it..