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Discussion Starter #1
Anyone gain top end speed by going down one tooth on their front sprocket? I seem to have gained some on my ZX-6RR although I do have a new exhaust and a PCIII also. :D
 

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Going down a tooth on the front will DECREASE theoretical top speed. Going up teeth in the front or down teeth in the rear will INCREASE theoretical top speed.

With your new sprocket - you should see a torque increase at all RPM's, but the bike will require higher RPM's than it did before to go the same speed.
 

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Yes and no. If you do not have enough power to pull in 6th gear going down one tooth will pick up top speed because now you can reach your redline. The 636 and any other streetbike has enough power to reach its top speed without having to gear it down a tooth so in that case it would slow you down.
 

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But you'll get to your top speed faster.
The only way to really tell is to make one modification at a time.
I geared my ZX6R down three teeth on the back sprocket and have the same top speed as before, but the bike wouldn't pull redline in sixth with the standard gearing and wheezed up to top speed. Now it gets there much more convincingly.:)
 

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Plus: with the speedometer sensor located at the front sprocket housing, you'll be recording higher speeds and mileage than you're actually covering. This is probably the most direct reason for the "increased top end."

I've read that there's a gadget you can buy which corrects the speedometer reading to compensate for sprocket changes.
 

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Discussion Starter #6
Thanks everyone for your input. 99gixxer before I changed the sprocket I could not see my shift light(14,000 rpm) in 6th gear. I can not only see it now my bike is still pulling at 14,000 rpm's. I achieved a top speed of 151 to 154 mph according to the speed calculator before the sprocket and now according to the calculator I'm running between 161 to 164 mph. Since the sprocket was the last thing I put on I'm not sure if it was the total cause or if the combination of pipe,PCIII and sprocket helped me achieve this speed. Oh yeah even though I got to 161-164 the bike could have done more but I ran into traffic. :)
 

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Do you mean you have one of those speedo correcting black boxes on your bike?
The combination of the exhaust and PC111 would have been what really increased the top speed, not the gearing. Full exhaust systems have a really big effect on the top end of bikes, which when you wind them out, results in a higher top speed, assuming the bike wouldn't pull redline in top gear when standard.
My bike wouldn't pull redline in sixth when standard. I bought a full Muzzy titanium race system, rejetted it and Woohoo! an extra 20kmh or so at the top end. I now have the standard exhaust back on with lower gearing and it accelerates faster than it did with the Muzzy and standard gearing but does not reach the same top speed. I don't ride at that sort of speed much anymore anyway so I don't miss it or care that it is "lost".
 

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Discussion Starter #9
Yes I was talking about the speed calc. in the tech forum although it would be be nice to have the black box. :D
 
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