flywheel bolt comes loose

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flywheel bolt comes loose

24 Feb 2021 11:49
#844010
flywheel torque for 750b? I replaced the starter clutch on my 750b. I have torqued the flywheel bolt to 100 ft/lbs and after a few starts it loosens up. Am I missing something?
78 KZ750B

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  • Scirocco
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Re: flywheel bolt comes loose

24 Feb 2021 12:52
#844016
The torque for the alternator rotor bolt should be 70 Nm = 51 ft-lbs.
Looks like you have over tighten and stretched the bolt.

My 1975 Z 1 B 900 Project

www.kzrider.com/forum/11-projects/605133...ears-deep-sleep-mode

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Re: flywheel bolt comes loose

24 Feb 2021 14:19
#844023
I am an idiot... i was using in-lbs and not ft-lbs. Need another hand to do 100 ft-lbs. I have a 78 750b by the way.
78 KZ750B

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Re: flywheel bolt comes loose

24 Feb 2021 14:24
#844025
Torque spec for a 78 750b is 87-101 ft-lbs
78 KZ750B

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  • DoctoRot
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Re: flywheel bolt comes loose

24 Feb 2021 21:27 - 24 Feb 2021 21:27
#844054
I found it impossible to hit the torque spec with out making a rotor holder.
'78 1000 Long Term Project
 '80 750G
 750 Twin Big Bore Track Bike
Last edit: 24 Feb 2021 21:27 by DoctoRot.

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Re: flywheel bolt comes loose

25 Feb 2021 10:42
#844095
DoctoRot wrote: I found it impossible to hit the torque spec with out making a rotor holder.

I had to borrow a second hand and a strap wrench. Got it all torqued and it didn't come free yet after 10 or so starts
78 KZ750B

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  • DoctoRot
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Re: flywheel bolt comes loose

25 Feb 2021 10:55
#844097
Nice! I presume the new starter clutch solved your problem?
'78 1000 Long Term Project
 '80 750G
 750 Twin Big Bore Track Bike

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Re: flywheel bolt comes loose

25 Feb 2021 12:46
#844100
DoctoRot wrote: Nice! I presume the new starter clutch solved your problem?

Yep...the kz400 was a direct bolt in. Not one skip. I did save the new springs, pins, and dowels from the messed up one for when this one does fail.
78 KZ750B

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Re: flywheel bolt comes loose

25 Feb 2021 16:52
#844112
Well that didn't last long. I was periodically starting it today. Spun loose again. I am lost. The manual says nothing about thread locker but should I use some or should try to get a new flywheel bolt?
78 KZ750B

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  • DoctoRot
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Re: flywheel bolt comes loose

25 Feb 2021 17:19 - 25 Feb 2021 17:22
#844113
If the bolt threads in by hand there is probably nothing wrong with the bolt. Are there any blemishes on the crank taper or in the fly wheel taper preventing it from seating? these engines spin backwards from so it should be tightening the left hand bolt when it spins. is there something in the thread preventing the bolt from going all the way in? pics might help.
'78 1000 Long Term Project
 '80 750G
 750 Twin Big Bore Track Bike
Last edit: 25 Feb 2021 17:22 by DoctoRot.

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  • urankjj
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Re: flywheel bolt comes loose

25 Feb 2021 18:14
#844114
Could a kick-starter shaft serve as a rotor holder ?

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  • Mikaw
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Re: flywheel bolt comes loose

26 Feb 2021 09:43
#844134
Woodruff key?
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
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Jimi Hendrix.

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