In my opinion, this is a fascinating topic! A reduction in unsprung weight and rotational mass will make a big difference on your bike by making it more nimble and giving a small bump in horsepower! In these two videos, I am documenting the process of replacing a 520 chain and sprockets with a lighter 415 size. I am also replacing the mounting studs for the rear sprocket with 8mm shorter Titanium studs. This will simplify the process of swapping wheels at the racetrack since the studs won’t be protruding as much and, therefore, less likely to get caught in the chain. While doing this work, I’ll also replaced the rear disc rotor with a Galfer Wave.
In the 2nd video, I had to deal with some challenges when shortening the 415 chain. I will publish another episode in the next few weeks talking about a new chain tool specifically for this chain size.
The total weight savings are considerable. Here is the full list:
|Item||OEM Weight||New |
|520 chain vs. 415||1633g||971g||662g|
|Rear Axle nut and washer – replaced by TI components||56g||38g||18g|
|Rear brake rotor||824g||577g||247g|
|Studs for sprocket carrier||205g||107g||98g|
|Total savings||1592g (3.5 lb)|
This overall weight reduction will undoubtedly improve the amount of horsepower and torque redirected to the back wheel. According to some information shared by Norton-Motorsports1, these changes should result in an extra ~0.6 HP and an increase in torque of approximately 0.3 lbf·ft (Yes, this is the correct way to represent pound-foot, which is the unit of measure for torque).
Since the 415 chain is much thinner, you need to be aware that it will wear/stretch a lot faster than a 520 chain. Be prepared to frequently adjust the tension and replace it with a new unit after a few weekends on the track. With the absence of O-Rings, you will need to give this chain a lot of TLC. I’d recommend cleaning and lubricating it after every 2-3 hours of riding.
The tools required for this job are:
- Impact wrench with 30mm socket (for the front sprocket nut) OR a 1 1/8 wrench
- 12mm wrench for the chain tensioner/adjuster
- 14mm socket to remove the sprocket nut
- Propane Torch (optional) to simplify the process of removing the rotor bolts
- Torque wrench
- Chain breaker tool
- 18 and 22mm sockets wrench to remove the back wheel
- MotioPro chain alignement tool
- Loctite (Red and Blue)
- Chain cleaner
- Oil/Wax/Lube for the chain
- Disc cleaner
Parts for the bike:
- SuperLite Rear Sprocket 15T (Part # 13814X-55:415)
- SuperLite Rear Sprocket 17T (Part # 13814X-57:415)
- SuperLite Front Sprocket (Part # 27502X-18:415)
- Complete Titanium Hardware Kit for Unsprung Weight from Norton Motorsports
- Galfer – Standard Solid Mount Wave Rotor (DF461W)
- Locking Front Sprocket Nut – Yamaha part #: 90179-20010-00
- Chain – DID 415ERZ
If you plan on doing this work on your bike and wanting to preserve a similar gearing/behavior as the stock OEM chain/sprocket gearing ratio, you will need to get one of the following sprocket combos:
- 18/55 = 3.05
- 17/52 = 3.05
- 19/58 = 3.05
The OEM setup is:
- Front: 14T
- Rear: 43T
- Resulting in a 3.07 ratio
Enjoy the videos and don’t forget to subscribe to my YouTube channel to get quick access to new content.
1 – You can get the all the performance details here.