Author Topic: frame bending  (Read 408 times)

Offline coater87

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frame bending
« on: 05.04. 2017 23:16 »
 Not a question, just some observations.

 I had my frame, swing arm, and about everything else powder coated on this bike. Then of course I put new swing arm bushes in.

 Today I installed the swingarm (had to spread the frame a little). I swung the arm and the passenger foot peg loop interfered by about 1/8 of an inch.

 Now I know that when I spread the frame, it was no more than maybe 1/64th of an inch. And regardless would not have effected that loop anyway.

 So I used the tried and true Harley methods and bent my frame to work, not to be confused with "straightening" the frame. This involved a bottle jack, boards, and a number of heavy blows from a large hammer. The powder coat has survived fine, and the swing arm is almost perfectly centered between the loops for now. I will have to check again tomorrow morning to see if it set or if the frame is going to try and spring back a little.

 Everything was lined up great before powder coating. I am wondering now if the temperature they use to bake on the powder (about 390 degrees) is enough to add or remove stresses in the metal.

 Or maybe the new bushes are to blame.

 I really dont know *conf*

 Lee
Central Wisconsin in the U.S.

Online Peter in Aus

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Re: frame bending
« Reply #1 on: 06.04. 2017 01:16 »
Hi Lee, some where on the forum there is a bit about the SA bushes, the ones you get now are to long, when I fitted mine I had to trim some off the inner sleeve of the bush, I think about 1/8".
Peter

Busselton West Australia
49 A7 longstroke
58 A10  SA

Online KiwiGF

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Re: frame bending
« Reply #2 on: 06.04. 2017 05:54 »
Not a question, just some observations.

 I had my frame, swing arm, and about everything else powder coated on this bike. Then of course I put new swing arm bushes in.

 Today I installed the swingarm (had to spread the frame a little). I swung the arm and the passenger foot peg loop interfered by about 1/8 of an inch.

 Now I know that when I spread the frame, it was no more than maybe 1/64th of an inch. And regardless would not have effected that loop anyway.

 So I used the tried and true Harley methods and bent my frame to work, not to be confused with "straightening" the frame. This involved a bottle jack, boards, and a number of heavy blows from a large hammer. The powder coat has survived fine, and the swing arm is almost perfectly centered between the loops for now. I will have to check again tomorrow morning to see if it set or if the frame is going to try and spring back a little.

 Everything was lined up great before powder coating. I am wondering now if the temperature they use to bake on the powder (about 390 degrees) is enough to add or remove stresses in the metal.

 Or maybe the new bushes are to blame.

 I really dont know *conf*

 Lee

Is that 390 deg F or 390 C ?  If centigrade then that might be hot enough to make the frame move about....if F, , then not, just my opinion!

I ground a mm or 2 off the new bushes I fitted, as the inner tube stuck out more than necessary and it would easily not fit in the frame otherwise.

New Zealand

1956 A10 Golden Flash (1st finished project)
1949 B31 rigid “400cc” (2nd finished project)
1968 B44 Victor Special (3rd project,in progress)
2001 GL1800 Goldwing, well, the wife likes it
2007 KTM 950 Adventure, cos it’s 100% nuts

Offline duTch

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Re: frame bending
« Reply #3 on: 06.04. 2017 08:58 »


 Can't give any constructive help other than to suggest this to be a prime example for taking measurements and photos of anything that may matter later >BEFORE dismantling< , and not just frame related, not to say you didn't though *smile*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online bsa-bill

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Re: frame bending
« Reply #4 on: 06.04. 2017 09:03 »
perhaps a simple theory of mine.
the first set of bushes I installed, I installed into a S/W arm that had a internal stop midway, not having done the job previous I thought the stop would be to enable the bushes to knocked in to the correct depth.
However in a discussion here it seemed that not all S/W arms had this stop, in face few has IIRC.
So is it possible there was two lengths of bush one for stopped S/W arms and one for the rest.
( I have spent the last 18 months on heavy painkillers - you should perhaps take this into account when reading  my mails *eek*)
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline BSA_54A10

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Re: frame bending
« Reply #5 on: 06.04. 2017 15:46 »
There are several swing arm bushes as used on A 7 /10 . A 50 / 65 . B 31/33 & C15-B44.
Bike Beesa
Trevor

Online JulianS

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Re: frame bending
« Reply #6 on: 06.04. 2017 16:14 »
The centre tubes of the bushes are longer than the outers and are inserted until they meet in the middle of the swinging arm.

There are 2 types -one for the swinging arm with a solid 5/8 inch spindle and the other type with larger bore to take the crossover brake shaft.

beezermacc

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Re: frame bending
« Reply #7 on: 06.04. 2017 17:18 »
Hi Lee, some where on the forum there is a bit about the SA bushes, the ones you get now are to long, when I fitted mine I had to trim some off the inner sleeve of the bush, I think about 1/8".
Peter

That depends on where you buy them from... ;)