This weekend we sat down with the TIG torch and got to work on welding the new swingarm and although not quite there with it (we've ran out of gas) a lot got done and we're now not far off.
From the previous post, we had the initial lower section tacked together, before test fitting it to the bike to make sure everything cleared. With this all good, we were ready to weld - but there was a change to make first.
The pivot tube made initially was 1 1/2" with a relatively thick wall. The counterbore for the bearing was machined from this, therefore creating the greater tube thickness in the middle of the tube. This created extra unnecessary weight so we changed the plan. Now we have gone with 1 5/8" x 16swg CDS tubing, but have machined bosses that are welded in either end to take the bearings. These are currently undersized, ready to be machined in line on a boring setup we are making on the lathe when the welding process has done with distorting my once straight tube.
With the lower half fully welded (and checked for distortion (the two legs pulled in 9mm!)) and re-positioned to where they should be, the top half of the swingarm could start to be tacked on. Again, it was very much a case of tacking a few bits on and checking on the bike. This was especially important to enure the shock, exhaust and chain cleared all the tubing.
You can see the large cut from the front tube that has been shaped around the shock. There is very little space between the shock and chainline.
Once popped out of the jig, access to the joints became easier to weld and it was all going so well until the Argon ran out. So this is the stage we are at, with a couple more cross braces to add and a few welds to finish off. Then we can look at machining the bores for the bearings and correcting the distortion that has occured on the top tubes where they meet the aluminium block at the the rear.