It is very easy to understand why Mr. Hallman didn't like HL500 at all because his team had a new proposal for the season '78 with a revolutionary 4-T engine made by Nils Hedlund. The extremely light engine had a 4-valve head and had numerous innovations used some 20 years later by Yamaha amongst others. The project deemed too expensive and the proposal had been rejected. Maybe the main reason was, however, that the factory had lost its interest in 4-T mx bikes and concentrated 2-T monocross bikes only. Bengt Åberg himself liked his factory "Hallman & Eneqvist etc.) bike that much that he continued with "his" Hallman Team bike as a privateer in '79 resulting 13th in World Championships.
The factory bike had been developed all the time during '77 season. In its original shape (pictures in this topic) the bike was not long. Bengt didn't like AirShoxs's, so Öhlin and occasionally Bilstein products were used. The rear shocks had alternative fixing points in the swing and frame and it seems to me that Bengt preferred more lateral positions. See Luxembourg pictures (in this topic as well). The Hedlund 3-valve head was very seldom used. During the season Bengt's mechanic Bror "Julle" Haglund made numerous alteratios planned and tested by father and son Lundin. During the season the team got help from factory mechanics as well. They assembled a CDI-ignition and made some minor improvements. The ligter wheel hubs were assembled. In the end of the season the bike's weight claimingly was only 102 kgs, 3 less than YZ 400C. The HL project was a swede-free one. Their opinions can be told later if felt interesting.
Lennu Jr..