Did you see this sticky: http://www.cbr250.net/forum/cbr250-performance/11141-performance-forum-gearing-thread-index.html ... this index has a number of threads listed which pertain to final drive gearing.
Sprocket for higher top speed?
Hey guys, just was wondering if anybody has found a good sprocket setup for getting a little more top speed? Before i say anything else i want to say that im not looking to go over 100 AT ALL, but with the riding that ive been doing and will continue to do, i dont exactly like the feeling of ringing the cbr's neck to stay with the crowd, we constantly ride at around 75 ( yes i know thats speeding, and its also illegal, spare those comments please, i know the potential consequences) but this thing is revving constantly at like 8,500 rpms at that speed and so has anybody came up with a good sprocket set up for that? The 250 off the line keeps up with every one of the bikers i ride with, because they have cruisers and so we do just that, cruise. I realize im going to have to sacrifice some low end torque but im not looking to win any races to begin with. Thanks in advance!
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Two cheapest options:
1. 7% higher gearing. Fit a 15T front. Not sure about the States but i can get one here for less than $20.
2. 6% higher. Slap a CBR300 sprocket on the rear. It has two less teeth than the 250R (36 vs 38)
1. 7% higher gearing. Fit a 15T front. Not sure about the States but i can get one here for less than $20.
2. 6% higher. Slap a CBR300 sprocket on the rear. It has two less teeth than the 250R (36 vs 38)
Have you owned the bike from new? Check that it's already on standard gearing. At 75mph it should be turning about 7300rpm not 8500.
Or he could use the 6 gearHave you owned the bike from new? Check that it's already on standard gearing. At 75mph it should be turning about 7300rpm not 8500.
0
I go (ride) with the 300R chainset.Two cheapest options:
1. 7% higher gearing. Fit a 15T front. Not sure about the States but i can get one here for less than $20.
2. 6% higher. Slap a CBR300 sprocket on the rear. It has two less teeth than the 250R (36 vs 38)
I changed in january.
It's probably the easiest solution.
And (here) the 300R chainset cost, on the bike @ a Honda dealer, less than 100 US alltogether!
would this also help in fuel mileage too? ...I know, I know kind of the opposite of 'trying to go faster', but if I were to be at a constant 60 or 65 mph, the RPM's would be lower too and one would assume, less revolutions per minute, less fuel?
...........or am I totally off base??? (I'm new to bikes, but in cars this makes sense too)
...........or am I totally off base??? (I'm new to bikes, but in cars this makes sense too)
For me, it's about the same.
Still 3.3 l/ 100km
Only it does look like 3.5l
Because the Odo is now 6% behind
(of what he showed before)
http://www.cbr250.net/forum/608513-post655.html
but I have to say, I pretty much drive "ear controlled".
And looking on the Speedo, every now and then, tells me,
I still ride 100 @ 6krpm, where I did that before, too.
Which means, I drive now about 6 % quicker in daily average
Still 3.3 l/ 100km
Only it does look like 3.5l
Because the Odo is now 6% behind
(of what he showed before)
http://www.cbr250.net/forum/608513-post655.html
but I have to say, I pretty much drive "ear controlled".
And looking on the Speedo, every now and then, tells me,
I still ride 100 @ 6krpm, where I did that before, too.
Which means, I drive now about 6 % quicker in daily average
Great site to help you understand the different sprocket sizes and what they do - Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator
Depends on the region I think. Speedo's are a bit optimistic in places. Here in the states, it is apparently spot-on by my measurements, but my tach reads ~6900RPM at 65MPH.Have you owned the bike from new? Check that it's already on standard gearing. At 75mph it should be turning about 7300rpm not 8500.
cford, many have changed to a 15t front, but this does affect city riding. Usually, many report that the CeeBee doesn't have the balls to really pull any harder with a gear change at the top end, and many say their top speed is actually reduced by changing the gearing. Thinking in an extreme case but applicable, severely reducing the final drive would allow you to theoretically do 60MPH at 4kRPM, but the bike doesn't put out enough HP at those revs to hold that speed. So reducing higher speed RPM doesn't mean you can go faster necessarily.
It may sound/feel like you're ringing its little neck, but trust me, it's built for it and loves it. I contemplated changing gearing, but stayed with the factory gears for several reasons, and not wanting to fool with a speedo healer. Honda knew what they were doing when the paired the gearing combo with the engine characteristics for daily riders.
It may sound/feel like you're ringing its little neck, but trust me, it's built for it and loves it. I contemplated changing gearing, but stayed with the factory gears for several reasons, and not wanting to fool with a speedo healer. Honda knew what they were doing when the paired the gearing combo with the engine characteristics for daily riders.
Do you know whether your bike has the original stock sprockets?... we constantly ride at around 75 but this thing is revving constantly at like 8,500 rpms at that speed and so has anybody came up with a good sprocket set up for that?...
Reason I ask is that with the stock 14T front and 38T rear sprockets, you would see aprox. 7500 RPM @ 75 MPH in 6th gear, not 8500 RPM.
Have you owned the bike from new? Check that it's already on standard gearing. At 75mph it should be turning about 7300rpm not 8500.
C'mon Mike, get with the game! :laugh:Do you know whether your bike has the original stock sprockets?
Reason I ask is that with the stock 14T front and 38T rear sprockets, you would see aprox. 7500 RPM @ 75 MPH in 6th gear, not 8500 RPM.
Not often one gets a chance to pull you up, couldn't resist :wink2:
As far as i know its got the stock gearing, i could be wrong though, as i bought my 2012 with almost 2,000 miles on the odo, and i do not know the original owner.
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Counting the teeth will soon tell you.As far as i know its got the stock gearing, i could be wrong though, as i bought my 2012 with almost 2,000 miles on the odo, and i do not know the original owner.
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Actually I did see Keith's post, and since the OP hadn't yet replied to the question of what size sprockets were on his bike, I thought it couldn't hurt to ask the question again.C'mon Mike, get with the game! :laugh:
Not often one gets a chance to pull you up, couldn't resist :wink2:
Dam, shoulda known...Actually I did see Keith's post, and since the OP hadn't yet replied to the question of what size sprockets were on his bike, I thought it couldn't hurt to ask the question again.
This is an important factor. You may drop your RPMs by gearing up, but you may end up revving too low for the power required to overcome drag.cford, many have changed to a 15t front, but this does affect city riding. Usually, many report that the CeeBee doesn't have the balls to really pull any harder with a gear change at the top end, and many say their top speed is actually reduced by changing the gearing. Thinking in an extreme case but applicable, severely reducing the final drive would allow you to theoretically do 60MPH at 4kRPM, but the bike doesn't put out enough HP at those revs to hold that speed. So reducing higher speed RPM doesn't mean you can go faster necessarily.
(SNIP)
Ninja 250s run 10,000 RPMs at 75 mph - all day long.
Make sure your oil is good, and the level is correct. Then don't sweat the revs.
You can get a pretty accurate gauge of the actual speed of a 15 front/38 rear on this video, which is from a track day so all legal. I synced a gps to the camera footage so it's "real" and not speedo speed that you are looking at on the screen, and you can compare the rpm to it directly in real time.
I put the 15 on the front to try to get a higher top speed at the track, and use the lower end torque better for my daily work commute. I'm much faster cornering now than in this footage which was a while ago, but even so I just hit the peak speed of about 147 - 150kmh earlier, rather than continuing to accelerate. The straight here is a downhill gradient so you need to take that into consideration also. The top gps speed I have recorded there is 157kmh, but I had a decent tailwind that day. I am in 6th on the throttle stop all the way through turn one so you can see as soon as I move into the wind it slows into the 130's - the power is just not there.
The 15 gets bogged down in the uphill corners, I'm going to change to a 13/36 next.
https://www.youtube.com/watch?v=Y_qeeYlxBDs
I put the 15 on the front to try to get a higher top speed at the track, and use the lower end torque better for my daily work commute. I'm much faster cornering now than in this footage which was a while ago, but even so I just hit the peak speed of about 147 - 150kmh earlier, rather than continuing to accelerate. The straight here is a downhill gradient so you need to take that into consideration also. The top gps speed I have recorded there is 157kmh, but I had a decent tailwind that day. I am in 6th on the throttle stop all the way through turn one so you can see as soon as I move into the wind it slows into the 130's - the power is just not there.
The 15 gets bogged down in the uphill corners, I'm going to change to a 13/36 next.
https://www.youtube.com/watch?v=Y_qeeYlxBDs
You can get a pretty accurate gauge of the actual speed of a 15 front/38 rear on this video, which is from a track day so all legal. I synced a gps to the camera footage so it's "real" and not speedo speed that you are looking at on the screen, and you can compare the rpm to it directly in real time.
I put the 15 on the front to try to get a higher top speed at the track, and use the lower end torque better for my daily work commute. I'm much faster cornering now than in this footage which was a while ago, but even so I just hit the peak speed of about 147 - 150kmh earlier, rather than continuing to accelerate. The straight here is a downhill gradient so you need to take that into consideration also. The top gps speed I have recorded there is 157kmh, but I had a decent tailwind that day. I am in 6th on the throttle stop all the way through turn one so you can see as soon as I move into the wind it slows into the 130's - the power is just not there.
The 15 gets bogged down in the uphill corners, I'm going to change to a 13/36 next.
https://www.youtube.com/watch?v=Y_qeeYlxBDs
That is very helpful thank you! And also, where can i get a set of fairings like you have? Those look great!
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I hear an engine rattle at 1:17!!! And pucker factor at 2:44. :grin2:You can get a pretty accurate gauge of the actual speed of a 15 front/38 rear on this video, which is from a track day so all legal. I synced a gps to the camera footage so it's "real" and not speedo speed that you are looking at on the screen, and you can compare the rpm to it directly in real time.
I put the 15 on the front to try to get a higher top speed at the track, and use the lower end torque better for my daily work commute. I'm much faster cornering now than in this footage which was a while ago, but even so I just hit the peak speed of about 147 - 150kmh earlier, rather than continuing to accelerate. The straight here is a downhill gradient so you need to take that into consideration also. The top gps speed I have recorded there is 157kmh, but I had a decent tailwind that day. I am in 6th on the throttle stop all the way through turn one so you can see as soon as I move into the wind it slows into the 130's - the power is just not there.
The 15 gets bogged down in the uphill corners, I'm going to change to a 13/36 next.
https://www.youtube.com/watch?v=Y_qeeYlxBDs
Is it just me, or does the front tire look a little blistered? :surprise:
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