When I first finished fabbing and aligning. The 85 Honda Sabre, and
the Vespa body road well right out the shop door. gravel road, to the
blacktop. 55mph smooth. So I disassembled every thing to do body work
and paint. Made a note of all the critical measurements. Reassembled
using the same measurements. At 35 mph. front shakes bad. The wheel
lead is adjustable. I've tried 8,10, and 12" Setting at 10". Seems
to help some. I'll give the measurements that I have at this point.
ballast 125#. toe in 5/8", 3deg.leanout. sidecar wheel is 49" off
centerline of bike wheels. Putting a scale under the side car wheel
with bike wheels blocked to the same height shows 230# Thats including
the ballast on board. The spring shock on the swing arm. is 2nd hand
spring is about right but not much shock left. (won't hold oil).
Sure would appreciate some words of wisdom. Thanks in advance Bob K.
What sidecar do you have?
Most of the Japanese cruisers will wiggle their noses a bit at a certain speed. Most of this is just a bother at first and one gets used to it.
The Sabre's have a lot of trail and the use of a steering damper on some combos is the best way to control head shake.
Here are a few things others have done to lessen or eliminate this phenomenon:
You can tighten down the neck bearings enough to eliminate front end flop.
Drop the fork clamps (triple trees) farther down on the fork tubes to lower the front end while reducing trail somewhat (If you do this be sure the wheel or fender won't hit anything when the suspension is fully compressed). You can raise the rear of the bike with longer shocks or a taller tire thereby reducing trail a bit. Check the alignment of the front and rear wheels to ensure true tracking. Add weight to or inside of the handlebars. Re balance the front tire and check the wheel for runout. Check the condition of the front wheel bearings.
Any or all these will help reduce head shake.
Lonnie
Northwest Sidecars
Lonnie, The sidecar chassis is homebuilt. The body is a Vespa I
bought from You about 2 years ago. Thanks for the tips.
I have found that small adjustment differences in the front-to-rear level of the car affects the toe in enough to generate "new" pulls, shakes, and shimmies when you disconnect/re-connect the car. The car axle camber also affects the toe in, and bad toe in generates wiggle and pull. It is always hard for me to get the brackets back "exactly" the way they came off, ya know. Jon
