Second what Scott said about the front drum. My former 45 has/had a Honda CB350 front drum which was fine, I never tried the Sportster drum, though. A few observations - I had this on both the track and registered on the street. The 34 mm Mikuni is the way to go. Others here will disagree, the I thought the Linkert was a PITA. The power is more than fine around town and occasional jaunts on the slow lane of the highway, but I wouldn't try much more than that. The engine is stone simple, and you can still get NOS parts wrapped in WWII era newspaper. You can get new hot cams, strocker flywheels, heads, cylinders, etc. These were dirt cheap at one time (before my time) but prices are a little crazy now for nice stockish examples. The stock three speed sucks and doesn't like being ridden in anger. I wasn't brave enough to try and rebuild mine myself, but I know it's a lot more challenging than a four-speed BT tranny. Also, avoid the later electric start Servicar transmissions with electric start. I can't remember the cutoff year, but they didn't have provisions for kickstart. If you haven't bought one yet, for the cost of a transmission and rebuild, you won't be far from buying a Samwell (probably the maker of your frame) brand new four-speed (looks identical on the outside). Did I mention how much I hate the three-speed? This was the only bike I've owned with a suicide clutch, and left turns from a stop took some learning. I used the stock 45 pogo seat, and added a valve spring (outer) from a Chevy 427 after bottoming out the pogo and compressing my spine a few too many times. Never tried one, but I heard some negative stuff about the DNA springers. I had a V-Twin repop and it was fine.