right now at 75MPH in 6th I am at about 8,000RPM. I want a little more go around 70-75 MPH.
For those of you changing gearing
What are you seeing RPM/feeling wise on it?
traffic flys at 75-80 MPH. If i stay under it's almost death.. Well on the freeways here. So I try to stay at 75 in the Carpool lane but most the time I find it wide open to keep it at 75
why would I want to go Up(front) Down (rear) if the bike can't even hit full redline in 6th stock?
my GSXR600 woudl not hit redline in 6th on a track in AZ. I did -1/+2 and was able to hit redline in 6th without a problem and the bike pulled the whole time..
so what would +(x)/-(x) gearing help if the bike doesn't have the power/gear reduction to pull it's own weight?
I just noticed. Your sig. shows you having a few things done to your 250. Mine is 100% bone stock.
My wifes has a two bro's slip-on and I can tell her's is faster. it also will do 85 with me on it without a problem
I changed the sprockets on my Ninja250R and it made for a much taller and more usable 1st gear, but I don't think the CBR needs it. The stock gearing is the best I've seen on any 250. I'm taking a "if it works, don't mess with it" approach to my CBR compared to going crazy with mods like I did with the Ninja. The CBR is as close to perfect as I've seen in a 250cc street bike in many respects. It doesn't cry out for mods as urgently as my Ninja did.
Mine will pull redline in top 171kph but takes a big effort to get there.
It indicates 162kph on a flat road in good warm still conditons.
On the track I'm getting flatout in 5th but the straight is short.
Going to try a non Oring chain to release a couple lost hp.
That combined with a 39T or 40Twill be about the best setup.
Right out of the gate, I'd like to say gearing lower didn't do anything to the fuel economy. No loss. No gain. Here's my review of the setups I've tried...
14/38 (stock): Peak HP @ 85mph. 68mpg. Mild ride. Very little 6th gear torque. 13/38 (-1F): Peak HP @ 80mph. 68mpg. General/practical. Adequate 6th gear torque. 13/40 (-1/+2): Peak HP @ 75mph, 68mpg. Assertive ride. Useful 6th gear torque.
You can plug the values into gearingcommander.com to get the values you want. Just change the "peak power" RPM to 10,500 (red line) since that's the RPM it uses in most of the calculations. For reference, 6th gear red line for -1/+2 is 93mph if I remember correctly.
Keep in mind how much wind drag affects small engine bikes. Gearing taller could slow you down if you can't tuck tight enough. I have a higher top speed with -1/+2 than I did stock, all though at a much higher RPM. I couldn't get stock past 80mph. Evidently I'm a natural wind sock. Some of the guys on this forum are awesome and hit almost 100mph. Your results may vary. I just geared mine to maximize rear-wheel torque for the speeds I use.
With the stock gearing I top out in the mid 80s rolling on 6th. If redlining 5 and shifting to 6th I can get into the 90s, or just going down hill. Close to 100, she's a little unstable.
Since you can hit a higher top speed with -1/+2, but with a much higher RPM are you worried about long term effects to the engine?
I would have thought that gearing that tops out the horsepower at 75 instead of 85 would decrease the top speed. Or is torque needed more at top speed because of wind resistance?
IMO, the 250R should have been geared 13/38 from the factory... 14/38 is too tall, sixth gear doesn't pull it very well. That said, I don't think that going any lower will gain anything other than the ability to pull easy wheelies. I wouldn't want to sacrifice the top end speed, with gearing any lower than 13/38.
While stock is geared a little high given the limited HP, it should be known that 13/40 doesn't turn it into a wheelie machine or anything. I can pin the throttle in any gear and it won't stand up. It's really a matter of how much torque you want out of each gear. As a street rider, I benefit more from increased pull at the crack of the throttle than an increased top speed (for example, needing to accelerate in traffic without having to downshift is quite useful). Honestly, I've never even tried to reach top speed with the new gearing because I haven't had a needed to, but I hit peak power at 75mph pretty often.
I also have a helluva time keeping freeway speeds about half the time i ride. I live in southern san diego and ride westbound to work about 20 miles with some crazy winds. If i had known this going into it i wouldn't have bought a bike that struggled to keep 72mph in 5th gear. Dont get me wrong, my windless and street rides are great but California is no place to be the slowest vehicle on the freeway.
Same here in MI, we get some pretty strong winds. I was riding home the other day through some strong gusts and going uphill against the wind I could barely maintain 69 mph.
You feel like you're sitting still while traffic blows by you at 80 mph. I've pretty much just made it a rule to avoid the freeway whenever possible. Unless I'm in a real hurry to get somewhere I take the back roads or state highways.
I disagree... after I installed the 13T sprocket, the bike can actually accelerate in 6th, without having to downshift to 5th. For example, if I'm cruising at a steady 60 MPH in 6th, the engine is turning 7000 RPM and has no problem accelerating to higher speeds from there. Not to mention the fact that 3rd, 4th, and 5th gear are much more effective in terms of quicker acceleration.
Changing to a 13T front sprocket is probably the single most effective, low cost performance improvement that you can make to this motorcycle.
@Asako: A lot more than you think. I promise you, $70 on a front and rear sprocket is way better bang for the buck than $700 on a slip-on and fuel controller. The latter, more expensive route is the major trend, and commonly done. People want the look and sound of the pipe and get sidetracked into the performance, which ends up being a secondary concern. I've tried the pipe/controller route, and it made very little difference. The sprockets are night and day comparatively. As Aufitt had said, you could take pretty much any bike, drop a tooth in the front, and that's the way it should've came. I don't know why, maybe tradition, but people are ready to dump 10x the money into exhaust without question, yet won't try a $20 front sprocket. Glad you're trying it out. I have a feeling you'll love 6th gear on the highway now.
Top speed this morning, on a flat stretch of freeway at about 7000 feet above sea level was 89 MPH @ 10,500 RPM. Air temp was at 40 F. My bike has an FMF Apex slip on, 13T front sprocket, air box cover removed, and a SpeedoDRD (speedo corrected and verified by radar).
Check out the gearing commander, just Google it and put in your bike.
You can then input different front and rear sprocket values and it will show you mph or kph in 1st thru 6th gear at 3000 to 8500 rpm. Has saved me from buying the wrong sprockets to change my gearing!
A rider weight* of 146 lbs. is very light, I'm sure it pulls fairly well in top gear for you. I weigh 200 lbs. with all my gear (full leather), so for me the bike struggled in 6th gear with the stock 14T front sprocket... gearing is not a 'one size fits all' proposition.
just this morning i was checking my valve shim clearance trying to figure out why my top speed upright was only 135kph....150kph crouched
then i looked down at the front sprocket cover and noticed there were 'marks' on the sprocket cover bolts....hmmmm....cracked the sprocket cover off and what do i see ? A freaking 15 tooth in the front. (DDC brand)....im not sure whether the previous owner put the 15t on or if it came from the dealer like that...but it would be interesting if other people who have the 135kph problem also have a DDC brand front sprocket installed.
Went immediately to buy a 14t and popped her in, top speed is now 155kph upright 166kph crouched. On a very hot 1pm afternoon.
I know the 15t threw the speedometer off, someone know the deviation? But i could absolutely not climb any higer after a certain rpm no matter how long i held it.
The 15t was actually not bad for normal riding or slightly aggressive riding, 14t much better though, easily hits rev limiter, 15t harder to touch.....13t and 15t will have the same appproximate top speed, it feels like....But 13t feels smoother and shifts better.
btw my valve clearance at 5000 kilometers was 0.27mm EX for both, and 0.22 mm IN for both....good enough. (i just ordered tapered feelers too 'just in case' but looks like i wont be needing them)
im still comparing the fuel mileage between the 15t and 14t, will report back after next fill up. But so far i think the 14t is looking better.
I currently have the 17/36 on the bike and after about 1000 miles of use, I think it is great. I am getting a solid 84 mpg on the interstate and don't have a problem with acceleration. Basically 5th is now like the factory 6th. I am running about 5500 RPM at 55 mph in 5th. (Easy to remember). I don't use 6th unless I am on the highway. Since I am out in the country, this works well as nothing is closer than 10 to 15 minutes of 60+ mph riding.
I installed a 40t Vortex last week and it gave me better acceleration in all gears plus shorter wheel base. The stock chain is long enough and you don't need to slip the clutch in first gear when pulling away on inclines. I'm pleased overall
I could not find a steel one anywhere
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