Thursday, January 15, 2015

Jigging up the frame

As you can read about in an earlier post when I swapped in the zx9R swingarm into my 7R machine, I used the same sine laws to determine the proper swingarm angle for this composite mish-mash of chassis parts.

What we have is a Muz frame, R6 forks (from the earlier 1999-2002 version), and a swingarm from a RGV125.  This swingarm is steel, and the pivot tubes were previously milled to allow a 17mm swingarm pivot to be used.  As I previously planned to use a different engine with this frame, I ground off all the other engine mount tabs.... some of them might have worked with the xt600 engine, but who knows?  Considering I need to line up front and rear wheels, and then sprockets, I am not going to lose sleep over cutting off tabs too soon.
You can get a sense of how things will line up.  The swingarm shock mount will be welded to the curve in the "banana arm", and then a mount will have to be fabbed on the frame tube itself.  Offset far to the left, this design solution is becoming more common.  The ex650, Aprilia Mana and Shiver, and a few custom designs have come up with an offset cantilever swingarm design similar to this.

Next step is to stop by Cycleboys for some fabrication input, as well as go about centering the front and rear wheels (the supermoto spoked rims) in the forks and then the swingarm.  More pics to follow.

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