Sorry no pictures for this update...
I had a look around the mess that I call the work space in my garage and found the "other" pair of springs that I thought were the fork springs. Well, it seems that they are actually the rear shock springs and what I currently have on the rear shocks are in fact the fork springs. With the correct (and much stiffer) springs now mounted on the rear shocks, the rear travel feels much more normal. Also the lack of rebound damping in the shocks is now much more obvious with the stiffer springs. It's a little embarrassing to have got them mixed up but, yeah... whatever... :-
Having the rolling chassis all together has been a real novelty because up until now whenever I want to move the bloody thing I have to lift it. Now I can wheel it all around the back yard making engine noises which has been almost as much fun as riding! I somehow resisted the temptation to wheel it into the living room so I could watch TV while working on it. It has also given me the chance to test out the side stand and it appears that the original CB350 side stand is too short when attached to my relocated (higher and further forward) mounting position. This allows the bike to lean over too far. So using a tricky sleight of hand involving spacers, drilling holes and cutting threads I've managed to fit the longer 848 stand using the CB350 pivot bolt. This stand has the added benefit of being made of aluminium and therefore being lighter.
Before pulling the rolling chassis apart to send off to be painted, I took the opportunity to measure up the geometry to get a rough idea of where the bike is at. In order to do this I had the bike supported so that both the front and rear suspension were at full extension but with the tyres still just touching the ground.
I first measured the vertical height from the bottom of the steering head. Then using a laser pointer I measured the distance from the centre of the steering head to the ground along a line parallel to the centre line of the steering head. Then using a theorem devised by a good friend of mine Pythagorus to work out the steering head angle. My measurement for the steering head angle was 32 degrees to the vertical. The honda manual tells me that the "caster angle" is 63 degrees. I'm assuming that the caster angle referred to is the steering head angle relative to the horizontal which converts to 27 degrees to the vertical. So pretty close but according to my measurements my front end wants to be lower or rear end higher to get the steering head angle back to standard.
This is a little confusing though because I have gone to a smaller wheel (18in vs 19in) which in theory should drop the front and steepen the steering head. But other things have also changed that could influence the steering head angle. For example the 848 forks vs CB 350 forks. Measuring the forks (from axle to lower triple clamp distance) gave 848 450mm vs CB350 498mm. So the 848 forks are shorter and therefore lower the front and steepen the steering head also! Mmmm
I then worked out the trail to be 173mm and it was at this stage that I decided I needed to maybe re-check my measurements because even the 848 triple clamp offset of 36 mm vs CB350 offset of 60mm would not account for 173 mm of trail! So my measurements are screwed and I'll need to do it all again. The only problem with that is that the frame, swingarm and various brackets are now off being blasted and painted. So it'll have to wait for now.