You had frame problems causing most of your instability. Did you ever try higher pressures after you fixed that?
Yes I did. The frame issues had the "high" speed weave coming in bad at around 55 mph. After we fixed that, I was good up to the upper sixties to around the low seventies. And at the time I was running the pressures that are on the DOT plate.... forget exactly what they are at the moment ? But dropping the pressure to those lower numbers finished it off.
The bike is now of course completely different. Center of gravity, distance of that and the riders weight from back axle plays a big roll is stabilizing this frames, that have a fair amount of flex in them. And depending on the rider, and his or her weight and riding posture plays a roll as well. More weight forward, I have found is important on these bikes. The more the better it would seem. It settles the frame down, and the front end will not feel as lite at high speed.... basically the front end does not pivot AS easy at higher speeds.
My bike NOW has a 120-80-18 rear tire, a 90-90-19 front tire.... Roadriders both. 13 " Hagons at the rear, YOUR perfectly dropped clubmans
, 20 weight fork oil, and the swingarm work. It is decidedly sporty and stiff if you will, and handles like a dream. Weight on that front end helps big time..... The rake angle has been shortend at bit with what I have done, BUT it IS light years better then what it was, both at low and high speed.
Weight over or closer to that back axle will have the opposite effect.... Lowering the front tire pressure, we in effect shifted a bit of weight forward and also increased the contact patch with the stiff and ROUND RoadRiders.