Ok, a little background on the classes I'm building this for while I stretch after cardio. Planning on trying for the season, 8 events, gotta try to be in shape, I'm 48. Last time I ran a season I was 42. 6 years can make a difference..
Mods, I hope the link above is ok, if not, sorry and please edit it out. I'll get around to posting the whole build here too.
I like the idea of smaller displacement classes, and I tried a Ninja 250 a couple of years ago, but it wasn't to my taste. CCS came out with a 500 SuperSport class last year which allows up to 650cc air-cooled twins. Bikes in the class will include R3's, Ninja 300's, and KTM RC 390's running up a class, but will also be open to the Honda 500, not to mention Aprilias, older EX 500's (these would be killer in the class), singles, etc, and the engine rules are way less restrictive on pre-'94 bikes. The winner of the national title down at Daytona last year was on an FZR400. So, there could end up being a ton of variety in these classes. I'm a 2v Duc guy, though, and I love racing Monsters, so the M600 made perfect sense to me.
I'm going to race this in 500 SuperSport and 500 Superbike, and build it to the more restrictive SS rules as I can then also race it in SB; A SB build would not be eligible in SS. As such, the rules are more or less as follows.
Bike must be a model which was sold through normal channels in North America
OEM Vin-bearing frame must be used
OEM forks, brake calipers, fueling system, air box, engine, swingarm and wheels must be used. Certain parts, such as engine cases, heads, air box, crank, rods, and transmission, etc, must remain as produced.
Minor engine mods are allowed, but compression must remain stock, and valve size cannot be changed. Carbs can be jetted/ injection mapped, and aftermarket exhaust and air filter can be fitted.
Seems restrictive, but there's still a ton of stuff which can be done. The bike can be lightened substantially, chassis can be optimized for geometry and weight distribution, and good suspension can be fitted.
With all this in mind, the bike I wanted was the single model year 2001 M600. It was the only year Ducati brought the bike here before they changed it into the 620, with 450 units reportedly sold. Many have assumed I was building a 620, and encouraged it, mostly for the more-powerful motor, but I'm doing the carbed 600 for a couple of reasons. First and foremost, the fact that it's carbed cuts down on weight right from the get-go. Light weight is going to be the biggest means of achieving performance with this build. As such, one of my benchmark criteria has been 9lbs= 1 HP. So, not only is the carbed bike lighter due to less ancillary hardware, I can also easily lose weight by running a constant loss ignition system (no charging system) as I don't have to power said hardware. Doing this instantly took more than 10 lbs off the bike, with 7 of that being rotating mass at the end of the crank. That's a +2.5% reduction right there, equivalent to 1+ free HP and a much faster spinning motor. I've taken a great deal more weight off it than that, but more on that later.
The other reason is the chassis. The 2001 has the same style rear suspension, with the hoop, as the earlier Monsters and the 851/888 chassis those were based on, and very similar geometry figures, too. The 620 utilizes the next-gen ST based frames, and I have raced one of those, an S2R1000, which was not so good. Granted, that bike has the single sided swing arm and all, but still. A buddy of mine who knows a great deal about racing also told me of another racer he knew who tried unsuccessfully to race a 620, said he ultimately just couldn't make the bike handle properly. So, the M600 was the bike to get. Next time I'll tell how I went about that.