So I’m looking into purchasing a new kart with an IAME KA100 and the previous owner is reporting that the kart needs new rear and clutch sprockets. Is this a big deal to change/fix? Is it expensive or need a pro to do it (I am relatively new to kart maintenance)?
Very straightforward. Worth doing as a DIY as from time to time you will change gearing for performance.
Just make sure that the clutch itself is not slipping.
Rear sprockets don’t cost too much, and are something you use to for setup. You’ll change them depending on the track. The front sprocket doesn’t wear nearly as fast, and is easy to do yourself, but does take a little more work. You’ll need to remove the clutch bell to change it, which if you have a good impact, it isn’t too difficult to do.
The gear ratio (rear gear/clutch gear) on the kart may not be the one needed at the track you’re going to use. Clubs and track owners sometimes post a recommended gear ratio for a track. The clutch gear on a KA will most likely be a 10 tooth. The size of the rear gear will change.
With both current gears needing replacement, replace the chain as well. There are two types, O-ring and non-O-ring. The non-O-ring chain will cost less, but will not last as long. Also it can be resized with the use of a chain breaker. The O-ring chain has to be purchased in specific lengths and can not be resized.
A chain lub for karts is needed. To prevent premature wear of the new gears, you will need to properly align them. Most common method today is with a laser device that attaches to the rear gear. The old method is to use a straight edge. As for chain tension, 15mm deflection at the mid-point between the gears is good.