With the rear wheel out of the way, it’s a good time to clean up the swingarm.
I have no intent on reusing the original chain, so out came the angle grinder with cutting wheel which made quick work of taking the chain off.
The original 16-tooth sprocket on the left and the new 15-tooth sprocket on the right. You can see the new sprocket has some mass removed as it lacks some dampening looking material. It probably doesn’t contribute to a great reduction in inertia in the grand scheme of things, but every little bit helps, especially on a sportbike engine where many parts are already mass optimized.
This is a better view of the lack of material of the new sprocket versus the original.
There’s not much mass reduction opportunity on the rear sprocket.
The new rear sprocket is a bit thinner than the original to match the new 520 size chain versus the old 525 chain.
1 comment
Great article Khiem. These ‘quick’ acceleration kits are great for road use bikes where standard gearing is usually far too long. Not that one front tooth makes a huge difference, but the longer wheelbase that you’re afforded by using a smaller front sprocket also has some beneficial effects – mostly moving the center of mass forward toward the front wheel helping hard acceleration and cornering.
I’ve got another new to me 675 Triumph I’ll be uploading more about soon as well as finally more track time to dial in the 998 next weekend. Thanks for the link.