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Sprocket question!

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Old 07-29-2012, 07:48 AM
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Default Sprocket question!

I know ive seen alot about sprockets but none have really answered my question. Im about to change my stock sprockets on my 06 cbr600rr but not for acceleration. I want to know what I can change them to so that gain speed. Also how much speed would/can I increase from a stock bike other than a two bros racing slip on. And how much acceleration would I possibly loose? I know its alot to ask for but im curious.
 
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Old 07-29-2012, 08:17 AM
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Check this link and enter your bikes info. It will show you what various changes
will do to the bike's ratio. Keep in mind, sprocket changes don't "gain/lose" power.
They just change where it is harnessed by the drive-train.

Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator

As far as exhaust changes effect on power...Without meticulous tweaks throughout
the ignition/fuel/exhaust relationship (by knowledgable mechanics), these type of
changes are mostly "feel-good" performance enhancements.

I'm not discounting the possibilities, just the typical results of most DIY efforts.

Hope this helps, Ern
 
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Old 07-29-2012, 11:51 AM
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First off, How many times have you hit the Rev limiter with your stock set-up?
It takes ALOT to get up to the rev limiter in final gear on these bikes, If your planning on getting near Busa top speeds you can forget it without alot of performance upgrades (Internal engine) this set-up is more or less useless and you will be giving up acceleration for nothing.
I would think twice before going this route but that is just my opinion.
 
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Old 07-29-2012, 01:36 PM
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The reason, on the street, to go -1/+1, is to increase fuel-economy.
Honda does a decent job of balancing the load for the average driver.
Enough ummfh to generate sales, and yet, still keep the EPA happy.

However, if you do a lot of hi-speed highway/interstate riding,
there is a pay-off in fuel savings. You don't need much of a drop in RPM (at 65-75mph),
to add up to serious bucks with gas at $3.50+/gallon.

I wouldn't recommend going beyond a -1/+1 setup.
Any more, and you run the risk, of losing too much bottom-end for the in-town riding.

Ern
 

Last edited by MadHattr059; 07-29-2012 at 01:39 PM.
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Old 07-30-2012, 03:26 AM
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I hit the rev limiter alot when I go down to the local races. We go across a 7 mile bridge. My reason for the upgrade is that my bud has a gsxr 750 and he has the -1 +2 and he out runs me by around 8 mph. Im just looking to be able to slightly out run him and make him look bad lol. Also what other upgrades are out there that will help improve without breaking my bank account?! Thanks
 
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Old 08-05-2012, 09:42 PM
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Originally Posted by MadHattr059
The reason, on the street, to go -1/+1, is to increase fuel-economy.
I'm thinking in terms of the gears on my bicycle here. A smaller front sprocket and a larger rear sprocket means I will be spinning at a higher cadence for the same speed. On a motorcycle, it translates into a higher rpm for the same speed. Thus, a decrease in fuel economy.

If he wants to for a higher top end he needs to go +1/-1, assuming the engine has the hp to pull it. The bottom end will suffer slightly.
 
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Old 08-12-2012, 01:21 AM
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Curious as to what ecm your running?

Its odd to 'easily' hit the rev limiter in top gear on most bikes. I'm wondering if yours isnt kicking in too early.

Its VERY common for stock RPM gauges and subsequently the rev limiter (Kicking in)to be off as much as 1000 rpm. Something to look at.

Also aerodynamics are HUGE at those speeds. Simply pulling in your mirrors could be worth more than 5mph. A great tuck, head inside the screen, flat back, knees and elbows tucked in etc.....try and get your entire body out of the wind stream....and NO bubble screen could be another 5 as well.
 
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Old 09-08-2012, 08:59 AM
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Originally Posted by RoadiJeff
I'm thinking in terms of the gears on my bicycle here. A smaller front sprocket and a larger rear sprocket means I will be spinning at a higher cadence for the same speed. On a motorcycle, it translates into a higher rpm for the same speed. Thus, a decrease in fuel economy.

If he wants to for a higher top end he needs to go +1/-1, assuming the engine has the hp to pull it. The bottom end will suffer slightly.
Correct,but I'd leave the front alone,one it has more of an effect,two-sometimes there is not enough clearance.The more you change the ratio,the more you're speedo will lose accuracy,however they are all off and sometimes you GAIN accuracy.Was I never a concern for me,I just didn't care.
I would drop two teeth on the rr,any more you're sacrificing accel too much,and where is the fun in that?
Other than that,a GSXR750 will always kick your *** unless the owner is a fat bastard and you're not.Now-add a 40 shot of nos with sneaky Pete bottles and wave goodbye as you go past....
 
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Old 09-20-2012, 09:19 PM
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You general principle is sound, however the ratio is not 1 to 1, as the front sprocket affects the ratio at an exponentail rate than the rear sprocket does. An example would be on a bike with the stadard 42 tooth rear sprocket, you will find for each single tooth removed or gained in the front sprocket you would need to add or reduce the rear by 2 teeth to equal the affect. Sticking to the rear for mod's is best unless you really are looking for a very specific ratio.
Keep in mind that increasing teeth at the rear will increase low end torque (ratio/RPM increase) but will sacrifice some of your top end power and speed. Most bikes (unless modified) trail off power after 6500RPM. Obviously the opposite happens when you reduce the teeth at the rear.
The affects from one or two tooth mods at the rear can usually be negated or helped greatly with exhaust and carberation mods. Open exhausts will generally hurt your low end response, so consider a bit more backpressure in the exhaust if your gunning for loads of torque. Also remember to run a colder plug if you plan to run higher RPMs... will help alot.
 
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Old 09-21-2012, 07:02 AM
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Who said the ratio is 1-1? And 1 tooth change in the front is not at all like 2 in the rear,its closer to 3.And most bikes trail off power after 6500?! Have you seen a dyno print out? Or do ride a v-twin? They start coming on the power at 7000 and the the newer 600's at about 8-9000.And no matter what you do to the bike geraing is always the cheapest most effective performance change,with the exceptions of turbos and nos.
And don't change your plug heat range,stock is fine.Dude I have been racing for 12 years,working with pro racers for over 20 and been working at bike dealerships for 25 years,don't start spewing advice unless you know what you are talking about.
 


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