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Rats, bent frame.... #780762 08/06/19 11:21 pm
Joined: Aug 2001
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KC in S.B. Online Content OP
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How does a frame get bent when the engine is mounted in it? I would think the motor would add strength to the mount area. How does 1 side get twisted / or bent?
Piecing together a mocked up A65 to take to the DMV in an attempt to register it and get a Title. Number shows it as a '66 frame. Got to the point where it's got wheels and brakes, and on the floor. Next step is put a motor in it, since the goal is " It has to LOOK like a motorcycle ", from the last couple we have done. Can't be a bunch of parts in boxes,............ so, making it look like a motorcycle.
Found a box of engine mounting bolts, checking to see which goes where and how long etc...... Rats, the front mount long stud will not line up to the other side! Photos show 2 studs in the mount holes, just to show the alignment. Looks like the right side frame tube must be twisted, as that stud hits the opposite side Fwd of the hole. How does this even happen? Worse yet, what to do to fix it??? May not be worth the trouble................

Attached Files
Frt Mnt issue.JPG (54.58 KB, 213 downloads)
Frt Mnt issue2.JPG (40.11 KB, 214 downloads)
Frt Mnt issue3.jpg (25.68 KB, 213 downloads)

Down to 1 BSA, 2 Triumphs, 1 '56 Chevy
1 '65 XLCH on the way to Japan!
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Re: Rats, bent frame.... [Re: KC in S.B.] #780764 08/06/19 11:59 pm
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kevin roberts Online Content
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you might as well try to fix it before throwing it out.

chain it down to an old car frame or something and put a longish grade 8 bolt through there. then heave on it with all your pipe wrenches at once and see if you can make the holes line up.

if it breaks you'll at least have tried.


every day you do not take a chance is a day of your life that you will never get back.
Re: Rats, bent frame.... [Re: KC in S.B.] #780780 08/07/19 4:40 am
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DMadigan Online Content
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I would check the headstock for square to the swingarm bolt holes. My first BSA A65 was was from a wrecking yard and had been side swiped. Dinged slider, chip out of the cylinder, dented side panel and bent rear shock. What I found later was the headstock was twisted and the front engine bolt lugs did not align after the engine was out. I had to clamp the frame down, put a long pipe through the headstock and heat the backbone and down tubes until I could twist it back.
If the heastock is square you could heat the lug until the braise softens and twist it back in line.

Re: Rats, bent frame.... [Re: KC in S.B.] #780795 08/07/19 10:39 am
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gavin eisler Offline
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For the DMV fit motor , leave out front mount bolt.

For riding, simply reverse the forces that bent the frame , easier said than done.
Dunno about twisting the lug, BSA often pinned lugs before brazing.
Look closely at the front down tubes, put a straight edge against them, guessing that one will show more bend than the other, a plumb bob and spirit level will be handy.
Use the spirit level to level the swing arm spindle plane, then check the headstock for true with the plumb bob. Once you know where the twists lie , start scheming up a jig to straighten,.

Last edited by gavin eisler; 08/07/19 1:04 pm. Reason: nonsense

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
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Re: Rats, bent frame.... [Re: KC in S.B.] #780798 08/07/19 11:15 am
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Ginge Offline
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That front bolt isn’t a million miles away. It’s only half a hole out. Worth trying to save for the sake of four or five hours in the shed.

Go with Gavin’s plan. Leave the bolt out (use a smaller diameter bolt). If you can get a title then you can invest in straightening the frame.

If you can’t straighten it at least you’ve got a titled (bent) frame to sell.

I’d get some reference marks around it on a sheet of ply or using straight edges of some sort ( Fluoro tubes?). Try and find out where the bend is. Then rethink the economics of fixing it.

It’s not a million miles away but you won’t know until you know!




Last edited by Ginge; 08/07/19 11:18 am.

'51 C11 in a '54 C10L frame..."The Bantam Eater"
'70 Triumph Trophy 500. Bottom end rumble awaiting diagnosis
'72 Triumph Tiger 650. Boyer wired back in, proper coils replaced, working on single point ground..
Re: Rats, bent frame.... [Re: KC in S.B.] #780800 08/07/19 11:36 am
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Ginge Offline
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Looking again....

Have you tried fitting the motor? Just ask because those pics might only indicate that both tubes have sprung inwards in the absence of the big chunk of alloy that spaces them apart ( the crank cases). Springing inwards would cock the mounts inwards.

Or it’s had a smack on one side around the forks hard enough to twist the headstock. When whoever removed the motor the damaged tube kicked inwards.

Or the frame ( less engine) has been dropped and pushed one tube inwards.

Measuring will tell all.


'51 C11 in a '54 C10L frame..."The Bantam Eater"
'70 Triumph Trophy 500. Bottom end rumble awaiting diagnosis
'72 Triumph Tiger 650. Boyer wired back in, proper coils replaced, working on single point ground..
Re: Rats, bent frame.... [Re: KC in S.B.] #780847 08/07/19 8:45 pm
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KC in S.B. Online Content OP
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I picked an empty case up today, and will try it in the frame ASAP. Report later.......... I'm going to do the Plan A: DMV 1st. Then sweat the small stuff ! Thanks for the replies.


Down to 1 BSA, 2 Triumphs, 1 '56 Chevy
1 '65 XLCH on the way to Japan!
Re: Rats, bent frame.... [Re: KC in S.B.] #780928 08/08/19 5:03 pm
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Dibnah Offline
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Plumblines from a template placed on the rafters of the lock-up can be used to create a benchmark with a known good frame, perhaps even a frame that's part of a functional bike, but were the frames of classic Brit bikes ever absolutely square and plumb?

Edit: strange smiley thing has appeared at the start of my post, no idea why.

Last edited by Dibnah; 08/08/19 5:05 pm.
Re: Rats, bent frame.... [Re: KC in S.B.] #780952 08/08/19 9:22 pm
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GrandPaul Online Content
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I'd do as Kevin Roberts suggested, but first check to see if it is one side, or the other, (or both) that is out of line. If it is just one side, work on THAT side.

Take a 2x4 to smartly smack the long Grade 8 bolt JUST A BIT AT A TIME until the engine mount bolt JUST runs through. No more than absolutely necessary.

Last edited by GrandPaul; 08/08/19 9:23 pm.

GrandPaul (does not use emoticons)
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Re: Rats, bent frame.... [Re: KC in S.B.] #780957 08/08/19 10:24 pm
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Irish Swede Online Content
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I suggest grinding a taper on the end of that Grade 8 bolt before beginning the smacking.
Make it into a cheap "drift" to line up those holes.

Re: Rats, bent frame.... [Re: KC in S.B.] #781009 08/09/19 1:22 pm
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gavin eisler Offline
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Is this the same bike that had very twisted yokes/ triple trees?

If it is look for a hump in the top tube and bends in the down tubes and a twisted steering head. get friendly with someone that has a "Moto liner " jig.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: Rats, bent frame.... [Re: KC in S.B.] #781156 08/11/19 5:14 am
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KC in S.B. Online Content OP
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Nope, this was a frame sitting so long I don't even recall how it got here. Anyhow, decided the stop wasting time and effort on the silly folly, and junk it or cut parts off if anyone needs something. Crazy idea .......


Down to 1 BSA, 2 Triumphs, 1 '56 Chevy
1 '65 XLCH on the way to Japan!

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