I am going to change my chain and sprockets on my 999S with one of those racing kits from B&C Express. This will drop a tooth on the front and add one to the back. I would like to know who has done this mod and wonder if anyone can tell me (A) What the top end will be reduced to, And will the speedo remain to be accurate ? I know there are threads already on this but they seem to be covering 749 bikes.
You should still easily see 150 at the top end and as far as the speedo goes then it should remain accurate as its driven off a speed sensor connected to the back wheel and not from the gearbox.
No doubt if I'm wrong someone will correct me, but to the best of my knowledge this is true!
Bear in mind the "racing kits" tend to down size the chain to a 520. It's not uncommon, especially on the 996's for instance but you may end up adjusting more frequently. It is a "race" mod.......... the chain is lighter. I've done a couple with STM sprockets without any real problems. If you want to change the gearing and retain stock chain size, simply buy the required sprocket sizes in 525 and use stock chain.
Today I took on board everyones advice and fitted a new gold 525 chain with standard front sprocket and a Renthal gold rear Sprocket with 2 extra teeth. I would like to say it made a difference however I rode it home in minus 2 temperatures in heavy Bristol traffic, I dont own winter kit as I am a fair weather rider and proud of it. It snowed and I was not able to get above 20mph. I arrived home in serious pain with the cold and have mild hypothermia. I am shivering, my torsoe is freezing but my head is sweating. My body feels like crap and my legs are wobbly but god does that rear sprocket and chain look good. Well worth the pain. Thanks all for the advice. I am going back out with my coffee to have another look.