Ironhead Bent swingarm mount, 73

[quakefiend420]

Looks like the PO smacked something pretty hard.

Any suggestions for fixing it? The back of the swingarm is about 1/2" off(not bent, I have another one that I checked it against).

I'm thinking of using the other swingarm and welding a nut in the left end, then getting a large bolt that fits the nut, then attaching 10 foot of pole to the end of the arms and trying to bend it back in place with ratchet straps.

Thoughts?

Pics incoming!


















Here's what else makes me think that the rear of the swingarm is out of whack. This is what sits between the fender and the frame, and it's chewed up as well...

[brianbbs67]

Post a pic so I can see what your dealing with

[billeuze]

I'm not quite following your problem or plan

Is the swingarm bent or is it the frame where the swingarm mounts?

either way, you'll need an acetelyne torch to heat up the frame/swingarm where you want it to bend. Other wise you just odn't have as much control. And to bend cold you'll need to bolt it to a hell of a sturdy jig. You'll need a jig of some sort anyway to get everything aligned.

If it is bending the swingarm legs you want to do. You should know that the 2 legs have to align with each other in all dimensions. Just bending till straight won't have them all aligned properly. You need a wheel, or a jig to mock up a wheel bolded to your swingarm. or to one leg of your swing arm as you bend so you can see the other end of the jig align exactly on to the other leg. Then of course the whole works had to be true to the frame (tracking with the front wheel).

It took me a whole weekend as I recall to properly straighten my swingarm. and it wasn't off by much to start with

[quakefiend420]

Originally Posted by brianbbs67

Post a pic so I can see what your dealing with

Can't really tell in a pic, it's the mount on the frame itself and it's not off by enough to be able to really see it.

[quakefiend420]

To clarify, the swingarm itself is not bent, I checked it against another that's known good.
The mount on the back of the frame is slightly tweaked, enough that the rear of the swingarm is too far left by a half inch or so.

I'm planning to modify the other swingarm to be able to bolt it very tightly to the frame mount, then putting leverage on it with a couple lengths of pipe, then bending the mount back into place.

[DR DICK]

something fishy here.

the arm mounts dead between the 4 rear motor mount points. if the forging bent between the mount pads i be really surprised.

seems the whole forging pair and mount positions would move as one.

in this case with top and front motor mounts removed the engine will be crooked in frame.

could it be what ever your using to reference the bend (rear fender?), is itself bent, making the arm look bent when it isnt?

[quakefiend420]

Originally Posted by DR DICK

something fishy here.

the arm mounts dead between the 4 rear motor mount points. if the forging bent between the mount pads i be really surprised.

seems the whole forging pair and mount positions would move as one.

in this case with top and front motor mounts removed the engine will be crooked in frame.

could it be what ever your using to reference the bend (rear fender?), is itself bent, making the arm look bent when it isnt?

Both mounts appear to have moved, as the swingarm bolt still slides through.

Any ideas on what would be the best way to measure it out? The reason that I believe the mount is bent is because teh chain was rubbing the fender, the rear wheel was kicked over to the left, and the fender itself appeared crooked.

I thought it was the swingarm first, so I bought another. Then when I compare the old to the new, they're exactly the same, leading me to believe that the mount must be bent.

If it's not, that would be awesome, but what would be the best way to determine that outside of what I've done so far?

[quakefiend420]

Also, looking from the rear of the bike, the right shock is tilted with the lower mount in towards the tire, and the left one is mostly straight.

[IronMick]

Originally Posted by quakefiend420

... The reason that I believe the mount is bent is because teh chain was rubbing the fender, the rear wheel was kicked over to the left, and the fender itself appeared crooked ...

The rear wheel is very often off center on these bikes. There are other reasons that the chain will rub on the fender.

Does your bike have the frame braces? These started in 1973. The fender may make contact with the left brace and need to be bent [hit hard with a hammer] to fit. Perhaps this has been done.

I am thinking that there is nothing wrong with the frame. Some pics with a tape measure against the parts in question would help greatly.

[quakefiend420]

I'll get some photos tonight. Thanks for the help so far.