Reporting back on my experience of attaching a Watsonian GP Manx to my swinging arm Golden Flash, which has kept me busy in a cold garage for the past three weeks.
I've now fitted new sidecar fork springs, 18T engine sprocket, 67 pitch primary chain and original looking rear shocks but with 126 lbs/inch springs.
I managed to get the axle lead down to 9" and brought the sidecar closer to the bike so the track is now 44 1/2". Toe-in and lean were as before. Went for a test ride and found the left turns were still heavier than rights, otherwise ok.
So yesterday I was back in the garage again to increase in the toe-in slightly. I was aiming for 7/8" to max of 1", but when all the fixings were pulled up really tight, sidecar body fitted back on and with my wife sat on the bike it ended up as 1 3/16" (30 mm) toe-in
. Lean out was 3/8" and as it was the end of the day I decided to leave it and have another go at it another day.
So this morning, being prepared to spend another day in a cold garage, I thought maybe I should go for a test ride first - just to see what it handled like with 30 mm of toe-in. Contrary to what I've read toe-in should be, to my surprise (and delight) it seems fine. Left turns are much the same as right ones now, but with a smaller track I was very wary of left corners. There's no noticeable difference in pull either way on a flat road at 30 mph (with hands hovering just above the handlebar grips). Next I put my 14 kg scissor lift in the sidecar to add some weight and went for another test ride and felt far more confident when turning left.
With the damper screwed down there is still some handlebar shaking when going slowly over bumps in the road but it's not uncontrollable when expected, so I'm going to leave it at this and hope the increase in toe-in doesn't end up scrubbing the sidecar tyre too much.
Regards, Roger.