At the 30,000 mile service the chain needed to be replaced. To my knowledge it had never been replaced.
The stock FZ1 is geared quite high which makes it very subdued even when doing 80 MPH on the highway. This behavior is great for MPG and long highway trips but is not very engaging for backroad riding.
That being said, when it came time to replace the chain I opted to replace the rear sprocket with one size larger (48T) than stock (45T). From the reading and gear ratio calculating I had done I was hoping this would be a nice compromise between relaxed highway cruising and the high stung impotence of the two sizes smaller (15T) than stock front sprocket (17T) that I tried a while ago. I was still a bit nervous though. If I didn’t like it it would be a fair amount of money down the drain and/or many mile later until I felt ok changing it again.
It’s been nearly 1500 miles now and I can honestly say that it is significantly better the huge majority of the time. On slower corners 2nd gear is smooth yet powerful, and on the highway 6th gear is also smooth but more wanting to pull away as it sits right at the bottom of the power band when cruising on the highway. In many ways it feels like I went down a gear. The new 6th feels a lot like the original 5th. It also still has some punch at around 7000 RPM whereas the 15T front sprocket took that away.
In conclusion: I would say unless you only want to ride casually on the highway, this simple modification is well worth looking into. It has made my gentleman’s sportbike much more fun to ride on the street.
48 tooth rear sprocket on a 2006 Yamaha FZ1