Ok guys. I'm new to bikes so please tolerate my lack of knowledge (stupidity). I have an 96 F3 with OEM sprockets. I want to decrease my top end RPM's. What way do I go for a sproket change? I will be riding in the 55 -60 mph range to and from work most of the time but do see some weeknd riding in the future. Searched the threads and it seem's everyone wants to do the opposite. I'm thinking less R's = better gas mph??

 

If thats what you want to do then you either raise your front sprocket size or lower your rear.

Here is a good site to play around with.

www.gearingcommander.com

 

As already said, go up in number of teeth on your front sprocket and lower on number of teeth for your rear. Be careful here though, you can go low on your cruising rpm and end up with worse mpg. There is a point where your engine is the most efficient. If you get out the powerband of the engine, it may cause the engine to work harder and fuel economy will suffer. Remember, these engines are rather high rpm and do not make really good power until your up in the R's quite a bit. I would suggest going one up on the front. Much more than that and the bike will be harder to take off with.

Also, if you really want to save of fuel, stay out of the throttle on take off. That is where a lot of fuel is used. Also, make sure your chain is well lubed and clean and make sure you run your tire pressure at its max. The higher pressure tires will have less rolling resistance. You can always lower your tire pressure for your weekend rides.

But in all honesty, your probably only going to see a slight improvement. I don't bother because I can't stay out of the throtte. If I ride easy, my bike (1000RR) gets high 30's. If I ride like I want to, I've seen as low as high 20's. Riding style makes up for the majority of your bikes ability to get good gas mileage.

 

Will I need a new chain?

 

You should always replace the sprockets/chain as a set. They imprint to each other and can cause excess wear if not replaced as a set.

Ern

 

Have you measured your gas mileage while running in town and out on the highway? I was under the same impression that the RPMs ran high, but I get better gas mileage on the highway at 70 mph because there is less revving from the start and stop traffic in town
-CBRF Mobile

 

Haven't ridden the bike enough to verify gas milage. Just bought it a week ago and putting a few items on it before it hits the road. So with the vast knowledge on the forum does anyone have a suggestion as to how many teeth to go up/down and stay in the power band of the motor? Is there a kit maybe already proven out for what I want to do?

 

The engine is tuned to get useful power from about 5-9k, try to avoid dropping your
rpm in 1st below 3k @ 15mph-ish. Other-wise, imo, you'll begin lugging the engine at
take-off, or be forced to over-rev, negating your attempts to increase fuel economy.

I would leave the front sprocket alone or you risk clearance issues. So that means any
change should be to the rear-sprocket.

Dropping 2 teeth, to 41 (the most, I would recommend) will get you a drop of 150RPM or a
-4.67%. Dropping 1 tooth (42 teeth) will lower rpm by 75, with a -2.33% for the rpm.

The gains do not directly translate into economy anywhere except at the top-speed
you will normally be driving at. So the more high-speed driving you do, the more you
will see this translate into savings. Around town, you can generally expect the fuel
consumption to remain the same as stock, if you stay off the throttle and don't try to
compensate for the slight reduction in torque.

The advice given here is based, on my general understanding, of the way this stuff works.
I am not an engineer and haven't done any testing under real-world conditions.

The numbers I quoted were gathered using the speed commander (referenced above).

The advice is based on my experience with my own various bikes and how they've subjectively felt,
after various drive changes I have made over the years and my driving style.

Take it all with a grain of salt.

That said, good luck and I hope this gives you some insight into how the sprocket set-up works.

Ern