A couple months ago on an impulse my girlfriend bought a 2008 Honda CBR600rr.  She hardly rides it and it lives in my garage so it's slowly becoming my bike.  I'm a new rider.  In fact never rode a bike until this thing came along.

The bike in question had the sprockets switched out by the previous owner for more torque/speed.  A larger front sprocket and smaller rear sprocket.  The speedometer was never re-calibrated so it is off by about 10-15 MPH at around 50-60.  So if speedometer says I'm doing 50 I'm really only doing about 40.  I've investigated and found they make modules you can put on the bike that will compensate the speedometer to match the new gearing.  Somewhere around $125.

A bigger issue for me (as a new rider) is it seems like the bike doesn't want to pull itself when letting out the clutch in first.  If I'm careful and the road is flat it'll go without having to throttle while letting out.  When there's a bit if incline or if I rush this leads to embarrassing stalls.

My question is: if I go back to factory sized sprockets (smaller front, bigger back), will that make it easier to pull out it first?  I should be able to get a new sprocket set with chain for about $200 and it should take care of my speedometer issue.

Thoughts?

LL

You've got some math backwards there...
If the speedo says you're doing 50 and you're doing 40, they increased the sprocket ratio (larger rear and/or smaller front).
That gives you more torque and less top speed, going back to factory sizes will make the gearing feel "taller" and will give you less torque at low RPMs.

The 600RR is a high-strung motor, it doesn't like to chug around at low RPMs, which may be why you're having difficulty taking off gently.

Count the teeth on the sprockets, I believe they were 16t front and 42t rear from the factory.

To calculate the final gear ratio divide the drive into the driven. (small sprocket into the large sprocket). Unless things have changed recently, the speedo is driven off the front wheel and the gearing should have no effect on what the speedo reads.

On the 600RR the speedo sensor is right behind the starter on top of the case.

Make sure your not just feathering it real easy when you take off. I don't know how to explain this, but like mentioned earlier that bike likes to rev, and needs to rev to make power. Don't be scared to wind it up and get moving. When I got my cbr I was doing the same thing because I was used to single cylinder supermotos that didn't mind being lugged around,

Yup.
The speedo sensor runs off the transmission's final output shaft. This has eliminated one of the annoying cables to the front wheel.

With stock gearing, you can expect the speedo to indicate ~10% higher than actual speed.

As others have already said, the CBR600rr's engine is built to rev.
It doesn't start making real power until the 10,000 rpm range. Racers and track junkies learn quickly to keep the RPMs up above 8-9,000rpm, and they make sure to use whatever gear (going into the turn) is needed to be in the 10,000+ rpm range when coming out of the turn. Racers on 250's are even MORE careful about this.

To get going from a standing start, run the engine up to ~3,000rpm while easing off the clutch.  Letting the engine drop below 1,500-2,000 rpm will risk killing the engine.
These inline-4s have CRAPPY torque at low RPMs.
They also have a wet clutch, so they are made to handle slip during take-off.

Thanks for the replies so far.  I am a noob to this stuff so please forgive any dumb questions or assumptions.

It would seem my main issue is simply technique.  The bike I rode for the MSF class didn't need much throttle to get going so I'm probably just trying to do it like that.

My thing is when I try to throttle at takeoff is it feels like: nothing ... nothing ... nothing ... AFTERBURNER.  I guess that's why I try so hard to start off with just letting the clutch out.  I will keep trying until I get it right.

Does anything think this kind of doohickey would work for correcting the speedometer?

Thanks,
LL

No experience, but it does look like they make one for your bike.
How have you checked to compare dash vs actual?  Many vehicle factory speedo's are off by a certain percent.  You might need to strap a phone or GPS to your handlebars to compare.

Smaller front and/or larger rear will allow you to start off more easily.  

It will also reduce your top speed, assuming you top out because of engine rpm redline and are not horsepower limited.

It will likely reduce your gas mileage, too.

So the previous owner swapped out the factory sprockets for a LARGER front and a SMALLER rear? Am I reading that correctly? Your speedo shows 50mph but you are really doing 40mph?

If so, then the previous owner did not hear the bike for better low end acceleration. At all. And it would explain your difficulty with starting off.

The CBR is geared for top speed. I'd recommend a factory rear sprocket with a one tooth smaller tha stock front for easier around town riding.

Good luck.

This is your friend:

Gearing Commander

The Speedohealer is a great product.
I had one for my 2002 Suzuki TL1000R.
Super easy to install, I used two GPS's when I set the Speedohealer.
Spot on at 15 mph, 50 mph and 80 mph.

This.  

I did this to all my FZ1's.  

And the Speedohealer is the gold standard for correcting your speedometer.  I really need one for my bike, but am too cheap to buy something that doesn't do something I can't feel or see (performance, comfort, of looks).  On a 55mph road, my speedo says 78mph when keeping up with traffic doing 58-62mph

I use this one on my FZ1. Works great, a little cheaper, and has a very small footprint.

12 o clock labs SpeedoDRD

We do have rules here!
& Pictures of the bike would be nice too!

 
It's all technique. As you already know, the bikes most MSF classes use are single cylinder low reving machines, and because they are light and have enough 800 rpm torque to pull from a stop with little to no throttle they are perfect for a beginning rider. The 600rr your girlfriend owns is not one of those and as such requires, for a new rider, about 2x -3x as many rpms to at launch. I would start with 2500 or so rpms and feather the clutch out. You can go to a big parking lot and in less than an hour of practice will learn how to time-match the clutch release with throttle increase for smooth acceleration from a dead stop.


Try not to go past 3000rpm when practicing from a dead stop but also, do not worry about the clutch, they can handle the learning process and another 20,000 miles with no issues. IF and a big IF you were to burn one up, they take about 30 minutes to replace and cost $150 so it's really not a big deal. The likelihood of burning up a clutch during zero start practice is about nothing. Really, unless you are reving to 7000rpm and riding the clutch for a 1/8 mile you will be fine.


IMO--Personally I would go back to the stock gearing as it has all the low end power you need and your fuel mileage will be a bit better and your bike won't be as loud and buzzing at highway speeds. It also won't be as jerky(on/off) with throttle input with the stock gearing. It's a personal preference so do what you like.


Just keep practicing starts in big parking lots help because the fear of accidentally running into a car is gone . Wear your gear. Have fun.

Yep.

It's entirely possible I misunderstood the gear swapping and they went the other way.  I'll see if I can get to the front sprocket this weekend and count the teeth and compare to factory.

The speedometer difference, however, is real based on tests with both me and my girlfriend leading the bike in a car at a specific speed.  I also have noticed it when passing one of those "Slow Down" flashing signs that show your speed.

After reading some of the replies I did try getting up to around 2000 rpm before letting out the clutch and it helped a bunch.  Just need to keep practicing until it becomes automatic.

I also discovered today that the kill switch might have some corrosion going on.  It's sometime doesn't want to start and even stalled a couple times.  While dicking around with things I noticed that I barely bumped the kill switch and it shut off.  A couple more tests confirmed a little bump would stall it.  While reading about cleaning or swapping I learned you're not supposed to use it except for emergency (class had us use it every time we stopped).  This is all so new to me

LL

Take a look at the sprockets. Each should have the tooth count stamped into the side, then we can give you a better idea of what's going on.

Don't practice trying to get the clutch out ( don't make getting your hand off the lever your goal ),  practice on slipping the shit out of it,  clutch control is a magical thing that is handy all over the place.  Find out where that 1/2 and 1/2 friction zone is and make it your bitch.

This. good clutch control will be the greatest thing ever the first time you hit heavy traffic that is nearly but not quite stopped. My commute if I get out of work late can involve doing over a mile at about 2mph, I'd be fucked if I hadn't put in the practice with the clutch.

I did some checking and factory sprockets are 16/42

I couldn't get to the front sprocket (didn't feel like pulling hoses and linkage to get cover off), but the rear is 44.  Reading around 15 seems a common swap size so it's probably 15/44.

Obviously my theory of going "back to a smaller front sprocket" was wrong.

Is there an onboard chip or something that knows the gear and RPM and calculates speed based on that?

I guess I'll leave the sprockets alone (ain't broke, don't fix) and look into a speedometer adjuster module.

Here she is:


LL

Speed is taken from a sensor on the output shaft (the one your front sprocket rides on).  Very similar to an ABS sensor.  #11 in this diagram:

http://www.partsfish.com/oemparts/a/hon/50540258f870021c54beba11/crankcase

You can ask other owners who know their gearing what their speedo says at X rpm in X gear to get an idea of what your front sprocket is (as long as they don't have a speedo adjuster).  

Nice bike!  Good luck with her!

Speedo DRD does the same thing and is a bout the size of a 50 cent piece (smaller actually). It is made by 12 o'clock labs. Motomummy is a great source for it and other parts you may need (chain and sprockets since they should be changed at same time). Also if they put a bigger sprocket on the front it wouldn't give more torque. It would do the opposite and give less pull on the low end but higher top speed. I ride a K6 GSX-R600 an just went with a -1 on the front an +2 on the back. It pulls like a son of a bitch now. I lost a little on the top end but that wasn't a big deal since 600's won't redline in 6th without a taller gearing due to drag created at those speeds.