The VL3 was a major revision of the 150 theme, and although at first sight it can be hard to tell it apart from the VL2 in fact there are many differences.
As part of the process of moving the 150 upmarket the VL3 gained the leg shield pressings of the GS – these being more curved and attractive to the eye. Also from the GS came a peak for the head light and a lock for the toolbox, and the larger petrol tank. The handlebars were slightly narrower than those of the VL2.
There were alterations to the wiring to ensure a better headlight beam, and the speedo now had a light. There was also an improved saddle, and the brake drums now had small fins cast into them in order to aid cooling. The optional spare wheel was moved from its rather unsightly position at the rear, and was now on the inside of the leg shields.
Finally the cylinder porting was enlarged, and a revised carb incorporating a larger main jet was fitted. These last two changes improved acceleration slightly, but did not affect the top speed which remained at 50 mph. Incidentally, the Technica series incorrectly lists the VL3 as merely a frame number variation on the VL2. (Quelle)
VL1M, Kolben fest