This is a 1972 Yamaha LT-2 100cc two-stroke grafted into a 1975 Kawasaki KV75 custom frame.

Major motivators of the modification:

retention of swing arm and motor mounts locations as manufactured by Yamaha

wheelbase increase of 5"

to have 100cc's (10HP@7500RPM, 7FT-LB TQ@7000RPM) with a full-synchromesh 5-speed  in a package similar to the Honda CRF50

Yamaha used "Autolube" back in the '70's, which is oil injection in conjunction with "Torque Induction" (reed vales)

12 March 2010

Current progress is as follows. Primary frame is welded in place. Engine is preliminarily mounted with exhaust to check for clearances of tank's prospective location, shocks, and the sub-frame fabrication.

This looks like where the tank will go, as close to the stem while still allowing unobstructed steering angles.

Tacked in place. I have the angular alignment (parallelism) of the swing arm to the top tube/stem within 0.1".

Here a MotoGuzzi-style sub-frame is required to put/pull the engine. It will consist of 0.618" steel pins welded into both tubes shown here. The mating sides will have a hole and clevis pin. As a bonus, I can still utilize the front engine mount.

The KV75 frame/swing arm vs. the LT-2 frame/swing arm. I gained 5 inches in wheelbase, while assuring that the swing arm and engine mounts are all exactly square as Yamaha manufactured them in 1972!.

As you can see, it's ALL motor now!!

14 March 2010

Fired engine for the first time in nearly a year, had to fiddle with the wiring harness a little bit to get spark. Mounted most of the harness, coil, etc. Found a leather bicycle seat in a box of misc crap that will be installed, as the CT90 seat pan I was bidding on (ebay) went for far too much money. I ordered two Bridgestone Trail Wing-2 3.5-8 tires, two Michelin 4.0-8 tubes, and 4 sealed Moose wheel bearings/dust shields.