babbalou wrote on 12/31/69 at 16:00:06:I think the motor would be great in a dirtbike. Light & torquey. I'd drop the gearing about 20% & let 'er rip! The problem would be the chassis though. 35 degree rake; the front tire would wash out easily & standing up would have you leaning back. Interesting idea though. That green scrambler looks cool!
No doubt the 35º rake needs addressing, but for one thing, as you change the height of the rear shocks up, and the triple tree offset, your rake and trail figures are going to change anyways. Also, besides raising the rear and changing the rake with longer shocks, it would be necessary to get a taller rear wheel/tire, as almost no 15" knobby tires, and very few dual sport 15" are available. The 17" (is it?) sprocket and spoke rear wheel from the GS series would seem a natural since it is already the one parts are being picked off of for the sprocket swap. At least that is the direction I would investigate first. However, it would be nice to find a cross reference part that had nice alloy rims.
You might actually only have cut down a couple of degrees of rake to get the spec in where you want it (if any). Personally I like a bit of rake and trail on an off-road bike. The super quick steering of a low rake angle can be handy in really tight woods or trials bike like riding, but for simple pleasure trail riding, having really tight steering gets annoying and tiring after a while. Just depends on how you intend to ride.
This is all daydreaming for me anyways... I've got to decide what I can do with my 4-speed next, as I don't think it will make a suitable dirt/tracker etc... Maybe a Cafe' with no intention of getting over 80-85mph? Optimizing for torquing around 25-50mph tight roads might be fun.
Could just bolt on a fat azz solo seat and big windshield; and add some really tall highway sprockets on it, so it would just go putt.....putt.....putt at about 75-80mph.
Then just not worry about having to slip the clutch to get her rolling in first gear!