How do you know if your frame needs to be straightened?

[Mr_Dunev]

A buddy gave me a '71 BMW R75, that is in pieces and has been moved around in storage since '99. The frame has a few dings/dents in it from moving it around I guess.

I plan on beadblasting/cleaning every part of the bike before putting it back together. If the frame does need to be straightened, should I do it before or after I clean it up?

Also anyone know what it costs roughly?

Thanks,
L

 

[Tim]

Pics would help. Unless it was crashed the frame should be straight. You could bang it around all day moving it and you're not going to tweak the frame.

The only way to know for sure would to either get it up into rolling chassis form and check alignment etc. or put it on a jig to see what's what.

What makes you think it might not be straight?

 

[Mr_Dunev]

I don't have any good pictures of it, but these are the ones he sent me when he told me about the bike. I can take better ones of the whole thing when I get home.

From what I know the bike hasn't been in an accident, but he said when he rode it, there was a wobble above 75mph. I told him it was probably his wheels, but he was pretty sure he had, had his wheels alligned/ballanced

 

[Tim]

Well, the correct approach with any rebuild of this magnitude is to assemble the bike, and then break it down again for paint etc. Not into running order, but slap the front end on and wheels - that will let you see if things run straight.

The frame could bounce around in a truck for years and not get bent. Only way that frame is tweaked is if it was run into the back of a car which could torque the steering tube, but the front end would be a pretzel before the frame bent. Or if it was slammed into from the rear end, but chances are the swingarm wouldn't move freely if that happened. If things look right and the swingarm moves easily / doesn't bind, then get it blasted clean, have a look at it for any cracks etc. and then have it powdercoated black and start building the bike.

You'll find a few of us on the board love our Airheads and will happily give advice along the way

 

[Mr_Dunev]

Well, the correct approach with any rebuild of this magnitude is to assemble the bike, and then break it down again for paint etc. Not into running order, but slap the front end on and wheels - that will let you see if things run straight.

The frame could bounce around in a truck for years and not get bent. Only way that frame is tweaked is if it was run into the back of a car which could torque the steering tube, but the front end would be a pretzel before the frame bent. Or if it was slammed into from the rear end, but chances are the swingarm wouldn't move freely if that happened. If things look right and the swingarm moves easily / doesn't bind, then get it blasted clean, have a look at it for any cracks etc. and then have it powdercoated black and start building the bike.

You'll find a few of us on the board love our Airheads and will happily give advice along the way

Thanks I really appreciate it! I am new to this so I am sure I will have more questions along the way. I think the only thing I am missing are the exhaust, tachometer and wiring harness.

I look forward to bringing it back to life.

Lucas