Hallo Mudme. Welcome and huge points for having your old trailer matching the new Berg so well! Glad to see the hounds are watching you suspiciously. They already feel the bike is part of the family.
Bike looks in remarkable condition. Body work rarely stays that nice, what with frequent endos, bouncing off trees, etc.
Ok, put bike on some kind of stand, with both wheels touching ground. Then pull out the swing arm pivot shaft. It is usually corroded. Polish it with sand paper till spotless, clean with new rag and WD40, coat with waterproof grease (Bel-Ray). Might need new proper axle nuts. Repeat this ordeal with every axle or pivot on the bike. While in there, try to clean and then stuff every external bearing or rubbing surface with that grease.
Pull tank off. Remove petcocks, they are nearly blocked. Service engine. Use new fuel filter. Etc. Spin wheel bearings with your finger. The rear ones might be rough. Chain guides ok? Master link damaged? You get the idea.
You might want to avoid taking liberties with the Husaberg name. I got heck for that once.
Serviced it today, new filter and oil, new plug cleaned and re oiled air filter, pet cocks were blocked pulled carby apart and cleaned it, man this thing is a ***** to start cold! Was fine once warm and ran great but very hard to start from cold!
So after completely pulling the carby apart and giving it a good clean now all I do from cold is turn the idle screw 3 turns and it starts straight away, fairly happy with that!