This is a thread about rebuilding and modifying my 1975 Commando MK3. It was my street bike for many years, and I've finally got around to building it into my idea of the perfect Commando. I posted some details on straightening and modifying the frame herecommando-frame-straigtening-t23185.html
and I'm now in the process of mocking things up to see how my ideas are going to work out, and to get some measurements for machining parts.
These two pictures show the frame and swingarm with empty crankcases installed. That let me check the steering head angle and swingarm droop angle with the lower frame tubes horizontal. In that configuration, the rake is 26 degrees, and the swingarm has 7 degrees of droop. Those are the numbers I expected, but it's nice to be sure before I start machining the fork yokes. I'm planning get 3.75 to 3 " of trail, still not sure exactly what I want. I'm using a set of Ohlins (conventional) Superbike forks, which have 43 mm diameter stanchions, and require wider separation that the stock Norton forks. Because I steepened the steering head angle, I'll need less offset in the yokes, and I'll also need them a bit wider because of the diameter of the sliders. I'm still not decided whether to make new yokes, or weld inserts into some Yamaha yokes, and re-drill the stem holes for more offset. The latter would be quicker and easier, so I'll probably go with that.commando-frame-straigtening-t23185.html
These are pictures with the Quaife 5-speed gearbox and electric starter bits (Old Brits kit) in place. Because I'm using Maney cases for the 1007 cc engine I'm building, and a crankshaft with pre-MK3 configuration, I'll have to do some machining on the cases to fit a MK II style alternator, and probably a modified MK 11 primary cover. Preliminary measurements indicate that I will be able to move the gearbox over a bit to the left, and still make the Old Brits starter work. On my old PR race bike, I moved the gearbox over almost 1/4", which gave me clearance for a wider tire. In this case, I don't think I can go that far, but it does look like I can still move it over a significant amount. On the PR, I had room for a really wide rear tire, but for this street bike, I'm only looking for a little more room.
That's it for now. Next step is to machine cases and then check everything with the belt drive installed. Then it all comes apart for final painting and assembly.
Oh yeah, before someone catches it, yes, I do have the shocks installed on the wrong sides. The pre-load adjustment knobs will be on the outside, not the inside.