Lightening The Stock Clutch

I drilled a hole in each clutch shoe to lighten it up a little. This has the same effect as stiffer clutch springs, making the clutch engage later. I have heard a lot of people say that this causes your clutch to be out of balance and it's not worth the time and others endorse it. I have never done a scooter clutch this way, but have used this method on other small engines. Each shoe had a round marking on it in the same location. I used these for the locations of my holes. I don't even know what size drill I used, just whatever looked good to me. In other small bikes this usually makes a small difference in engagement RPM. Others go all out and drill larger and/or more holes in the clutch for more extreme results.

I would have just bought stiffer springs, but haven't seen stiffer springs in the US. If you don't already have 2000 RPM springs, 1000, 1500, and 2000 RPM springs are easy to come by. Another solution is using springs intended for automotive brakes. I've never seen anyone say a specific make/model/year spring kit that will include proper springs for this (or any) style of clutch so it would involve measurements and/or taking your clutch to the store and bugging the parts guy.

Here's the finished product.

I let someone borrow my cam today, so it wasn't around to take a before pic. Here's an old one though, where you can see the markings on each clutch shoe that I used as my drill spots.

This clutch ended up engaging around 5,000RPM using 2,000RPM clutch springs.