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11/19/2023
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Commiefornia, CA, USA
Edited Date/Time
1/1/2024 10:36am
Manual state 77 ft lb, this is around the 3rd or 4th time putting this nut on, this last time (was not cross threaded), didn't even get to 77 ft lb before the threads broke off like a spring. is this somewhat common with these aluminum nuts?
Yes that aluminum nut will break easily. No need to use a torque wrench on it. Grease on the threads will also allow the torque to get much higher before the wrench clicks. Blowing out the threads like this is easy when using a torque wrench on a shaft with grease on the threads, like linkage pivots, etc.
Try this. With all the pinch bolts loose, tighten that nut until it starts spinning the whole axle (assuming everything is aligned, greased, and happy). Then tighten the brake side pinch bolts and then give that nut just an extra little snug. Take the bike off the stand, pump the forks and then tighten the non-brake side pinch bolts.
Ive had it happen on my 250 before, always thought that amount of torque on an aluminum nut was crazy. I have a 23 250f also and noticed the nut on that bike is steel.
threads are clean, no grease or anti seize.
yup, did exactly what you suggested in paragraph 2, except using a torque wrench. will try your suggestion of "just an extra snug".
I had the same thing happen to mine and started using a lower torque value. I'll give the method above a try
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FWIW, the torque spec on my FC450 is 25.8 ft/lbs on the front axle and 59 ft/lbs on the rear axle. 77 is crazy. I wonder if that is a typo on Yamahas part. The torque wrench is a good idea for aluminum fasteners.
Gen prior was mid 40s (still real high),or so... not a typo, but certainly way too much for a front axle. You'll have your manual zealots, but reality is often quite different or better
Man, 77 ft. lb. seems way high. Even as a manual guy, I would deviate from that number. (Paging Luxon!) I do it sort of like FGRO1 described.
captmoto
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yeah, crazy high for aluminum. here's a page from someone for a 2017-2019 manual, fourth to the bottom, shows 75 ft lb, i guess it's not a typo in my manual. yamaha went from steel to aluminum, no wonder why i am 50% faster. yeah, i'll go with a lower ft lb next time.
What about the rear axle nut, it's steel, manual calls for 92 ft lb?
Holy crap . . . and 105 ft. lbs. on the steering stem nut? Dang!
Make sure you are using high pressure grease on all threads. No bolt should be used dry. I do this for a living and torque on a dry bolt will cause more friction creating a false torque. The high pressure grease will allow a smooth torque with low friction to get a true torque. It’s a very important step that almost everyone overlooks.
Put torque wrench away….
Had this exact problem with my YZ125. Don't torque it to the spec in the manual or it will strip over time and it seems to do it out of nowhere. I was planning to ride one day and had my front wheel off doing a tire change and when I went to torque the front axle nut it stripped. Ended up tightening it as much as I could without it spinning and drilling a whole through the nut and axle so that I could put a cotter pin to keep it from trying to back off. I started torquing it to 60 ft/lbs and it's held up just fine with no noticeable problems. Haven't stripped a nut since.
yup, out of nowhere. 60lbs without anymore issues since, good to know, others say 45-50. ty
My KTM is the same specs and when I looked up the torque specs for someone's YZ250 the first time it took me 10 minutes to verify that what I was reading was correct. The rear is 90 ft lbs IIRC.
That torque number is way high.
Post a reply to: YZ125 - Is this normal with OEM front axle aluminum nut stripping/breaking