The 98 and 99 are similar, PDS and ignition were I think the major changes.
My 98 has over 30,000 km with only routine servicing and one major problem. This was valve seats breaking up which resulted in a new piston, valves and seats at 7,000 km. 3 SEM stators, the 3rd a rewind by Small Coil Rewinds that has only lasted about 20 hours. I have sent a SEM to sparks to sort and I expect it to be back sorted properly soon based on feedback on this site. Check the manual, change the reed valve under the clutch, and keep an eye on valve clearances. If they start to get loose, then the roller followers are on the way out. I let mine get a bit far and pitted a camshaft too. Run Delo 400 as discussed on this site, and change around every 5 hours. Get 10 filters for $75 from Ballards. Suttos are knowledgeable on the old bikes, and OrangeBerg is very helpful and skilled in the workshop. Get the suspension sorted, I recommend the genius Frank Pons at Biketek.
Lots of stuff in my gallery on my 07 and 98 here
http://www.husaberg.org/index.php?set_a ... _album.php
Discussion re oil in heaps of places, but also here
http://www.husaberg.org/index.php?name= ... torder=asc
Buy old dirt bikes on condition, condition, and condition. It helps too if the seller knows something about it and can show you a log book and his shed.
If its starts easy, and runs fine, then that should be a good start. The motors are noisy, a veritable bucket of bolts, so maybe get someone like Suttos to do a once over if you are not sure. If seller isn't interested then he may have something to hide.
501s go great, the FCR is not mandatory, but is probably the best thing you can do to them.
Come to the Force Ride next year and show it off.
http://www.husaberg.org/index.php?name= ... pic&t=6871
Cheers
Steve