415 Chain Conversion for the R3

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. 

Rear Galfer Rotor

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 
Weight Reduction  
520 chain vs. 415 1633g 971g 662g 
Front Sprocket 184g 139g 45g 
Rear Axle nut and washer – replaced by TI components 56g 38g 18g 
Rear Sprocket 775g 253g 522g 
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.  

415 chain and sprocket

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 
  • Dremel 
  • 18 and 22mm sockets wrench to remove the back wheel 
  • MotioPro chain alignement tool 

Chemicals required: 

  • 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.

Geek during the day, wine and cigar aficionado in the evening. You can find me on a race track in the summer time and wrenching on motorcycles during the winter months.