Frame Straightening

[Nourish]

I've just acquired an A7 rigid Frame. It looks like it was a 'Chopper' back in the 80's by the look of the body filler (Bondo) all around the brazed joints and I can only imagine that someones come off it with it having highway pegs on it as the front down tubes just below the front engine mount are bent, the primary side pulled back and the timing side pulled forward. Now does anyone have experience in sorting this sort of thing out? If it were heated then the brazed joints will melt so I gather it should be done cold?

[Rex]

Find someone with a MotoLiner jig. I think there's a firm in Swindon. Probably 30 minutes work to get it back dead-on.

[chaterlea25]

Hi Nourish,
I agree with Rex, You will need the engine plates, gearbox and crankcases bolted together in order to make sure the alignment is correct

John

[Swarfcut]

Depending on the model year the frame may be a bolt up variant. The front section was common to rigid and plunger frames, minor design changes to the front tank mounting (rubber rather than simple through stud) and later steering lock are of no real consequence. A replacement front section may be a better option.  The brazed joints are first pinned and will not simply pull apart if the braze melts.

  An Induction heater could be worth a try rather than the blow torch.

 Frame dimensions are on the Forum somewhere, I also found some plans on the US based Old Thumpers website.

 Swarfy.

[Radlan2]

       If you think this is beyond your capability and are looking for an expert the go to man is Terry Mead, Pluckley Kent. Maidstone Motoliner use him for specialist BSA and other classic work outside their normal service. He makes replica competition frames and the fittings like rearset lugs, footrest loops and tank fixing brackets for our bikes. 01233 840323
         Chris

[Nourish]

Don't know if it's beyond my capability until I know how it could be done. I did make a fixture to make a bolt up replica hard tail but never finished the hard tail. To put this frame on the fixture I'd have to cut the axle mount off as this is a one piece frame and it won't go on. I'd best finish the rear end off first I suppose!

[Nourish]

After seeing a picture showing the side car brackets I think this damage was just that. I machine up 3 pieces of fork tube and welded two of them to a piece of 2x1 box section . I  bent up with heat a piece of m14 studding  to make a u bolt and used the 3rd piece of fork tube to protect the frome tube shape. Tightening up the nuts on the u bolt  pulled out the bend in the tube  - pulling it a little more than required to allow for spring back - very happy

[muskrat]

G'day Nourish.
Nice work mate.
Brings to mind the old saying "necessity is the mother of invention", Australia was built on it!
Cheers