Broke another flywheel key :(

[1998yamahawarrior]

Well as you guys know I just fixed a broken key and had a fun rip the day I did. Pulled it back in the shed in wait for this weekend. Went to fire it up Saturday afternoon and it wouldnt fire up, tried a couple things to see if it was just a glitch or something. I knew the timing was dead on, so I checked the timing since its a dead give away of a broken key. And low and behold it didnt line up. Pulled it apart and sure enough sheared right in 2. So besides seeing if I can get a oem Yamaha one, has anyone come up with something thats harder to break than the stock key material. Everything is good to go in the motor so Im at a loss as to what is causing this for the second time. Any ideas or input are needed here, I was severely upset of not being able to show Jar-Jar off after everything I put into it this spring.

 

[jeffsyfm350x]

Well as you guys know I just fixed a broken key and had a fun rip the day I did. Pulled it back in the shed in wait for this weekend. Went to fire it up Saturday afternoon and it wouldnt fire up, tried a couple things to see if it was just a glitch or something. I knew the timing was dead on, so I checked the timing since its a dead give away of a broken key. And low and behold it didnt line up. Pulled it apart and sure enough sheared right in 2. So besides seeing if I can get a oem Yamaha one, has anyone come up with something thats harder to break than the stock key material. Everything is good to go in the motor so Im at a loss as to what is causing this for the second time. Any ideas or input are needed here, I was severely upset of not being able to show Jar-Jar off after everything I put into it this spring.

Are you to torquing the flywheel nut down and has you torque wrench recently been calibrated the will go out of spec after awhile depending which brand you have..

 

[MS_Warrior]

Didn't you make your own key this last time? I would go ahead and slap an oem key in there before I would jump to any conclusions. Just a thought.


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[lbjamm]

You prolly already know, but if it's not properly torqued or there is grease, oil or dirt on the shaft, they can slip. Had a guy once brought me a mower. Said he just rebuilt it but wouldn't run. I told him to check the key and he said it was new. So we checked any way and sure enough it was sheared. He had put anti seize on it so it would be easier to remove next time. Cleaned the shaft and put in a new key and no more problems. FWIW.

 

[pwgsx]

Oil gets all on that shaft, flywheel and key area. I don't see how wiping the oil off is going to stop anything from shearing.....

 

[lbjamm]

Is it not tapered. That means its basically a press fit. Key is just for alignment. Spray some brake clean on there to get the oil off, let it evaporate, make sure it is dry and torque the flywheel to proper specs.