IMO, the first thing you should do is contact the association that you’ll be running. There a many regulations covering the Rotax and you should me yourself aware of what you need to make this engine legal.
If your clutch has springs and shoes, you have an old clutch. If the clutch drum has holes in it, it is an old type. The new clutches do not have a vented drum and the clutch is one piece. A change in clutch drums came out a few years and all the associations I’ve race with require the new style drum. But upgrading to the new clutch also requires replacing the nylon gears in the crank case with metal ones. The new clutches are low rpm engagement and not adjustable.
You can manage with a single clutch drum as different size gears can be attached to it. But you’ll have to invest in purchasing a socket that fits the retaining nut and have the front of the socket cut flat to insure a good fit on the nut. For road racing, get yourself a 16t driver
Next, if your engine does NOT have the EVO upgrades, again check your racing association. You may not have to install any of the EVO grades or maybe just some. Some of the changes are replacing the wiring harness, new piston and rod, and a new carb.
The carb is fixed jet meaning that it can’t be adjusted on the track. If this is the first time with a carb like this, jetting software would be a very good idea. You’ll also need several jets, know how to change them out and how to set the floats
Make sure you know what you’re getting into with the Rotax. I’m not telling not to go with the Rotax. It is strong, reliable and probably a lot of fun at Mid-Ohio.
LAD Specialties customer / tony kart / rotax / kt100