Author Topic: how to tell if a bare frame is bent?  (Read 966 times)

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Offline the technological J

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how to tell if a bare frame is bent?
« on: August 13, 2012, 11:00:26 AM »
been working on my 74 and am nearing reassembly and am unsure if its bent  because the top rear brace isnt quite right




 the rear shocks didnt look quite lined up when i put them on but i had a few beers in me at the time so i didnt think to hard on it
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Offline Old Scrambler

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Re: how to tell if a bare frame is bent?
« Reply #1 on: August 13, 2012, 11:14:16 AM »
Put a level across the triple when it is exactly at center......if not level.....prop (shim) one side of the bottom of the frame to level.........now set the level across the rear frame..........it should be level.

If you don't have an accurate level.........set the frame on the floor and measure from each rear-frame tab to the floor (90-degrees) and prop on sides until equal........then measure the centered triple-tabs to the floor...........if not equal you either have a twisted frame or a sloped floor. 8)
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Offline lucky

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Re: how to tell if a bare frame is bent?
« Reply #2 on: August 13, 2012, 11:23:52 AM »
Put a level across the triple when it is exactly at center......if not level.....prop (shim) one side of the bottom of the frame to level.........now set the level across the rear frame..........it should be level.

If you don't have an accurate level.........set the frame on the floor and measure from each rear-frame tab to the floor (90-degrees) and prop on sides until equal........then measure the centered triple-tabs to the floor...........if not equal you either have a twisted frame or a sloped floor. 8)

The thing the frame is sitting on has to be level first.

You would have to use shims because of the kickstand mount plate.

OR.....Just drink 2 more beers!! LOl...lol
« Last Edit: August 13, 2012, 11:25:27 AM by lucky »

Online Don R

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Re: how to tell if a bare frame is bent?
« Reply #3 on: August 13, 2012, 01:03:26 PM »
I placed three 1" aluminum straight edges across the frame tubes where they are double. I could stand back and easily see the frame had a twist, they were all different angles compared to each other. turns out bike had done an endo and was patched back together. Got it free so I couldn't be mad, just dissapointed.
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Offline Really?

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how to tell if a bare frame is bent?
« Reply #4 on: August 13, 2012, 01:40:42 PM »
To me the hoop is not straight.  The neck may actually be normal. I remember the neck being discussed in a couple threads a couple years back. So I know the info is buried somewhere in this forum.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

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