Frame spreading

[realnutter]

OK, so tonight I've stripped all the odds and sods off my BMW R100 chassis, and begun to think about squeezing the engine in....

The lower frame rails of the chassis are about 25mm too close together to get the sump between, so I reckon a little spreading is in order.......

So the question is, how? I'm worried that if i just jack them apart, one side will move more than the other......

So I figure, break out the oxy, heat one side to a nice red colour, and jack it 12mm or so.... then repeat the process on the other rail....

The theory being that the heated rail will always be the one that moves....

Thoughts, please?

[coachgeo]

Just for shitz and Grinz tie off or brace the cold one so you know it won't move.

Im not a metal person but what about this processing making portions heated on the frame and or adjacent welds more prone to stress fracture or something to that affect?

[Curtis in Texas]

Before you start putting heat to anything and knocking the frame out of alignment think about this. Try notching the inside of the rails.
I'll go get a picture of one I did here recently.

This notch clears the engine oil pan without crippling the alignment of the head tube or weakening the tube any more than it has to.

[boutje]

Here a youtube film about spreading frame parts.

http://youtu.be/foDms6-LxSA