BSA Stan torsion bars
The other weekend when on the BSA Bosworth Bumble I was very aware Stan wasn’t handling the corners very well, and all during the ride I took then very steady. The BSA Ariel 3 has rear torsion bars which steer the rear end into a corner (3 wheel steer way before those Japanese put 4 wheel steer on cars). The problem occurs when the bars get worn down, they don’t steer the bike correctly. What happens is oversteer, at which point the rides leans more and turns the front wheel more, then all of a sudden the back end converts that into understeer and your off.
Nick made a very wise observation that swapping the bars around front to rear would put unworn ends into the front control cups and make for an almost new feel to the bike. Nick has done his bike the week before Bosworth and was happy with the end result.
Secondly Stan’s front fork bushes have also worn down, so today it was disassemble Stan almost to nut and bolt level and rebuild back up with a new fork and swap the torsion bars. I haven’t finished it all yet, as getting the cotter pins out as expected took some work.
After I had the two halves of the bike split I could get to the torsion bars, and boy they are well worn.
Swapping then around was just a matter of removing a pin and sliding the bar out of its mount, swapping it around and pushing the grove pin back in place, and then a rebuild of the bike.
Here are the worn ends.
Needless to say rebuilding the moped is not as easy as it is splitting it apart. The damn chain has defeated me today, never mind tomorrow I will sort that out, then its the front fork.
I have bags of the right size bearings as no doubt when I take the fork out ball bearings will run away!!