Hi Ray,
When the bike was stock I felt I was transported back to 1975 as far as suspension goes, it had all the bad habits of any of the four cylinder products of Kawasaki plus the wallow of a rubber mount Norton Commando with shot Isolastic bushings. What I found disturbing was the Dyna's tail goes right when spinning the rear wheel and kicks left under "very" hard braking, I blame this behavior on the wheel offset. This sounds like a damming condemnation of the motorcycle but there were things that were right, like the steering (light and precise / with a 29 degree steering head), the rear suspension geometry (cantilevered forward mount shock location with a long swingarm), its ability to rack up miles with out beating me up, and the best thing... that wonderful v-twin engine that makes the motorcycle feel alive when you hit the starter button. The rest could be fixed.
Tire wear, The front tire always show feathering wear on the right side and the rear wears true, I would get about 10K miles before replacement of the set (Dunlop K401 + K591).
When I started the project in earnest, the chassis was rebuilt with new parts (both engine mounts, swingarm pivot complete, SKF wheel bearings, real Timkins in the steering head, on and on), at 22K miles everything was toast, the worst item was the swingarm pivot, replaced with new factory parts lubed with CV grease, the plan on this is to revisit the pivot in a few thousand miles, if I don't like what I see I will machine a custom pivot that will last.
I did the vertical alignment before I started the offset removal project, I used a Mitutoyo Digital Protractor Model 950-318 with 0.05 degree resolution with a machinist blocks clamped to the rotors for a 90 degree reference.
Here is a secret, if you loop a rubber bungee cord behind the frame downtubes then around the fork tubes (with a little lube) it will hold the forks in place to establish your 90 degree reference also you can use bungees looped around the frame to keep the wheels from rotating and you can use wood framing wedges to level the motorcycle on the stand.
To eliminate the rubber wiggle I used Alan Sputhe's Positrac system which allows vertical movement but not horizontal movement, basically it pins the engine to the chassis with heim end joints and establishes the three points (with the factory top mount) that defines a plane, this effectively eliminates the chassis flex and takes all side loads off the rubber engine mounts (similar kits are made for the touring bikes). Because I can't leave well enough alone, I replaced the upper engine mount with a true heim end link because the Dyna upper mount was built from rubber sleeves with steel bushings pressed in, it looked like a heim end joint and was a pain to adjust, no jacking screw. I will post later about the Positrac kit.
Best Wishes: Mike
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Topic: Removing Rear Wheel/Chassis Offset From Late Model FXD'S (Read 4188 times)