Motor mount torque specs

1937u spec

All flathead topics
Post Reply
flatheadmatt
Posts: 10
Joined: Sat Mar 03, 2018 11:01 pm
Bikes: 37u

Motor mount torque specs

#1

Post by flatheadmatt » Sat May 26, 2018 4:13 pm

Hi! Ive done searches and checked my manual. I cant find a torque spec for the top and bottom motor mounts. Its a 1937U. I found a spec of 35 ft. Lbs for panheads. Will this work? I have gone off feel before but would like to know a more precise measurement if anyone knows. Cheers!



old man emu
Posts: 654
Joined: Sun Mar 25, 2012 7:00 am
Bikes: WLA Mk lll, civilianised
Location: Narellan Vale, New South Wales, Australia
Has thanked: 7 times
Been thanked: 6 times

Re: Motor mount torque specs

#2

Post by old man emu » Sun May 27, 2018 2:40 am

I doubt if H-D ever published torque figures back in the day. In most situations, it is possible to use generic data calculated from bolt strength and diameter to determine an appropriate torque value for a given situation.

Here is a link to a table of generic torque values for bolts of various diameter and thread counts. Using these values will keep you out of trouble.

http://www.repairengineering.com/bolt-torque-chart.html

Remember that the bolt is the weakest link in the "nut and bolt" system and the bolt will fail if a torque in excess of the bolt's shear strength is applied.

As an aside, I replaced the drilled shank bolt and castellated nut combination holding my 45" to the frame with undrilled bolts and nyloc lock nuts because I found that the castellated nuts came undone because of the vibration from the rough roads I use. Even using undrilled bolts and plain nuts lead to loose engine mounting.

flatheadmatt
Posts: 10
Joined: Sat Mar 03, 2018 11:01 pm
Bikes: 37u

Re: Motor mount torque specs

#3

Post by flatheadmatt » Thu May 31, 2018 4:51 am

Thank you for the info!

Buddhahoodvatoloco
Site sponsor
Site sponsor
Posts: 820
Joined: Wed Sep 07, 2016 7:13 pm
Bikes: 1969 FLF
1937 EL Sold
1949 rat bike Sold
1946 FL Sold
Location: san diego
Has thanked: 21 times

Re: Motor mount torque specs

#4

Post by Buddhahoodvatoloco » Thu May 31, 2018 2:52 pm

What a kewl torque sheet, thanks.
old man emu wrote:
Sun May 27, 2018 2:40 am
I doubt if H-D ever published torque figures back in the day. In most situations, it is possible to use generic data calculated from bolt strength and diameter to determine an appropriate torque value for a given situation.

Here is a link to a table of generic torque values for bolts of various diameter and thread counts. Using these values will keep you out of trouble.

http://www.repairengineering.com/bolt-torque-chart.html

Remember that the bolt is the weakest link in the "nut and bolt" system and the bolt will fail if a torque in excess of the bolt's shear strength is applied.

As an aside, I replaced the drilled shank bolt and castellated nut combination holding my 45" to the frame with undrilled bolts and nyloc lock nuts because I found that the castellated nuts came undone because of the vibration from the rough roads I use. Even using undrilled bolts and plain nuts lead to loose engine mounting.

Post Reply

Return to “Flathead and Servicar”