FZ1 Sprocket Exchange: Part I – The Shop

I’ve been sitting on a new Renthal 15 tooth front sprocket for my 2006 Yamaha FZ1 for a while now. I had been a bit reluctant to do it and also a bit reluctant to purchase the necessary tools for the job.

After the abrupt throttle roll, my biggest complaint about the 2006 FZ1 is that I rarely get into the “fun zone” of the rev range. These past two years I have been doing a lot of urban riding and while the FZ1 is very comfortable it can be a bit of a bore when not speeding through scenic sweepers.

I think I got tired of waiting. Last night I went to Sears and I purchased the tools for the job. I performed tasks in the following order:
– remove left pedal and gear shift assembly
– remove sprocket cover
– flatten sprocket lock washer
– remove front sprocket nut (I’ll go into a bit more detail later on this one)
– remove front chain guide
– loosen rear wheel axle
– move rear wheel adjusters in to create slack in drive chain
– remove stock sprocket

– insert new sprocket
– replace lock washer
– replace and tighten front sprocket nut to 100 foot pounds
– bend lock washer
– hand test chain and sprocket
– replace front chain guide
– adjust rear wheel to proper chain tension
– check wheel alignment
– tighten rear wheel axle to 50 foot pounds
– run engine in gear to check sprocket and chain behavior
– replace cover
– replace left pedal and gear shift assembly
– take a quick test ride


The above is how it should have gone, and mostly did go. After adjusting the chain I noticed a loose section and a tight section. To remedy this I walked the chain down a tooth on the rear sprocket toward the tight section. I then proceeded with the rest of the list.

As for removing the front sprocket nut: For this I started the bike on the center stand and using an 18″ breaker bar and a 36mm socket tried to remove the nut. This quickly propelled the bike off of the center stand requiring me to catch it. Plan B: On the side stand, holding front break, repeat…. nothing. I then grabbed a fence post type bar and used it for additional leverage. Grabbing the bar about four feet off axis made it easy to smoothly loosen the nut.

Stay tuned for Part II – The Ride, coming soon.

4 thoughts on “FZ1 Sprocket Exchange: Part I – The Shop

  1. thanks so much for the info. never changed the ft sprocket, what tools did you need? also did you need to change the chain guide? I intend to use your suggestions . chuck warwick

  2. Thanks for the comment. I would never tighten my rear axle nut to 100 ft-lbs. Such a figure may apply to single-sided swing arms but not ‘regular’ swing arms. I also never had an issue with either my front sprocket or rear axle coming loose at those figures.

  3. What aboud Speedometer ? I also exchange Sprocket to 15 tooth, but speedometer dont’t show true speed…

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