Honda CBR 250 Forum banner

Sourcing 13T Sprocket?... expereinced only please

17K views 52 replies 23 participants last post by  ValleyOfMountains 
#1 · (Edited by Moderator)
First off i have tried to get the Renthal 368-5250-13GP with no luck from ATV shops and Dealerships, cycle gear alike.

SO MY QUESTION IS IF YOU HAVE IT AND ORDER IT WHAT IS THE EXACT PLACE WITH CONTACT INFO?

I have received a Sunstar sprocket with some crazy as spline design from the 80's era. I may even slip you $2.00 paypal for your info!

Thank you lord watch over my friends, family and my dog TURBO!

AMEN
 
#7 ·
... So since i have your attention where did you order it from?
Aufitt is in Australia... shipping would be a small fortune to the U.S. I'm pretty sure you can find this sprocket in the states. If you don't find the Renthal sprocket, the JT Sprockets (P/N JTF1321-13) is just as good, for half the price of the Renthal. Search for it using 1996 - 2005 Honda XR250R as the model application... searching using CBR250R won't get you anywhere.
 
#15 ·
Yes i do! not worried about a few mph, rather have a lil more torque in my lower gears as it suits my drive to work and play time.:)

Make your bike lose its top end speed...........
Wait the salesman didnt tell me there is a "top end speed" option,when i bought my bike!

But all in all people usually dont understand how much gears change the overall characteristic of a anything. Untill the them selves have spent time before and after the modifications.

So we should stop here, so nobody starts getting all engineer on us. My calculators say this and that, b.s. is for the birds. Although i would like to thank all the engineers in the automotive industry as a technican fixing there ******************** now for 16yrs, i have made a hell of a nice living and built a really nice IRA:D:D:D!

Thanks for the info on where to get them, i was going to pay the extra for the Renthal but i like $ on the JT!
 
#13 ·
Er... no, ever redline in 6th often?

If that was the case my highest speed at one track would be back struggling to get 130kph instead of the 142.2 it is now.
bet if I went lower again it would be near 150.

the gps does not lie.
 
#16 ·
Ok, so it gives you more torque in the lower gears? and a little less of a top speed?

I'd be happy with that since I don't really need to go faster than 80mph (and that's still breaking the limit) on my daily commute...but I do like to have that extra pull from the lights so I can get away from the traffic.

Any other pros and cons? Gas mileage change?
 
#18 ·
To add to what Rusty says above, I've found that I can use the next higher gear for a given road speed with the 13T front sprocket, while running at an RPM that is closer to the meat of the power band.

For example:
Gear _______ Road Speed (MPH) ______ 14T RPM _______ 13T RPM
6 ....................... 70 ........................... 7000 ................ 8000

6 ....................... 60 ........................... 6000 ................ 7000

6 ....................... 50 ........................... 5000 ................ 6000

5 ....................... 40 ........................... 4500 ................ 5200

Overall the engine runs better at these higher RPM's, and responds much better to further throttle input. The whole bike just seems more efficient... I haven't noticed any significant change in fuel consumption with the 13T sprocket.
 
#19 ·
'raising' ratios may take some edge off acceleration, plus lower rpm
in 6th gear, thus better mpg and easier on engine = longer life..
this may be 'good' for novice riders, and for the motorcycle..
you of course might wish to retain the edge on acceleration
plus bring 6th gear closer to 5th, away from 'overdrive'..

effectively, lowering countershaft teeth can increase, speed,
in the real world incl, on the flat, uphill, two-up, no long runups..

its not hard to imagine honda designing in ratios to include
considerations for novice riders and fuel economy/engine life..
esp for this motorcycle oriented to include novice riders..

lowering, countershaft sprocket teeth adds loading on chain and teeth,,
compared to changing ratio by adding teeth to driven sprocket..
also, apparently, odd teeth numbers are better than even numbers...
 
#20 ·
The bikes come stock with a general purpose gearing that would be usable to all people without modification. Changing the gearing to bias it towards how you want to use the bike's finite supply of horsepower is personal preference. Some want better highway fuel economy and a calmer ride; some want more acceleration and low speed control. Either way, the pro/con arguments on the physical effects on the bike are splitting hairs, honestly. That and sprockets are very very cheap compared to regearing say, a car.
 
#22 ·
as variously explained, acceleration will be spread thru the gears,
so yes, you will 'get more low end acceleration' but also similar
thru the other gears.. including 6th gear which will be a bit
more like 5th and less of an 'overdrive', thus you wont,
necessarily, 'lose top end speed' and in general use
could gain usable top end speed...

as rusty summarized, sprockets are cheap,
thus, its easy to suck it and see for yourself..
aufitt [i think] posted an excellent sprocket changing
how-to with detailed step by step and clear images...
 
#23 ·
I think what people mean when they say "low end acceleration" is actualy "immediate torque to the rear wheel". Yes, lower gearing achieves that. In fact, since it's by ratio (%), the higher gear you're in, the more you'll perceive the change. Dropping to a 13T front will make 6th gear usable to modulate speed in normal highway traffic without downshifting to 5th.

Don't forget to order an electronic speedometer recalibrator when you do. I recommend the 12 o'clock Labs SpeedoDRD.
 
#26 ·
I think what people mean when they say "low end acceleration" is actualy "immediate torque to the rear wheel". Yes, lower gearing achieves that. In fact, since it's by ratio (%), the higher gear you're in, the more you'll perceive the change. Dropping to a 13T front will make 6th gear usable to modulate speed in normal highway traffic without downshifting to 5th.
Exactly.

Don't forget to order an electronic speedometer recalibrator when you do. I recommend the 12 o'clock Labs SpeedoDRD.
I installed the SpeedoDRD as well. It's easy to use, and can compensate for the factory speedo error, rear tire wear, or a rear tire size change, in addition to sprocket changes... well worth the $80.00 USD price.
 
#24 ·
I don't see why you'd need more torque in lower gears than the single already delivers. Compared to a Ninja 250R the CBR is pretty quick off the line already and it's never had a problem delivering torque when I needed it.
That's the main reason I traded to a CBR from a Ninja250R. While I liked the changes replacing the sprocket on my Ninja 250R produced (taller gears, less shifting) it certainly didn't cure all the Ninja 250R's problems. I still noticed sluggishness in 1st & 2nd and I lost a lot of top end in the process. It was worth the mod, but just barely.
Not like it was the only thing I tried. I put hundreds (if not thousands) of dollars of mods into my Ninjette and it still didn't run or pull as well as my stock CBR250R does right out of the crate.
Maybe I'm just inclined to like the characteristics of a single over a twin, but CBR runs almost exactly the way I want a bike to run straight from the factory and I don't see any need to mess with sucess.
 
#25 ·
... I don't see why you'd need more torque in lower gears than the single already delivers...
Changing to a 13T front sprocket isn't really about increasing torque in 1st, and 2nd gear. In the first two gears the change with the 13T sprocket is virtually unnoticeable. In 3rd gear it is somewhat noticeable, but 4th through 6th gear is where it is a significant improvement in acceleration. My top speed now is 88 MPH, which the bike can easily accelerate to (although I rarely ride at that speed). With the 14T sprocket, top speed was 92 - 95 MPH and very dependent on ideal conditions. I am also at high altitude, which makes a big difference in performance... my bike has about 15 - 18% less horse power than it would have at sea level.

With the 13T front sprocket, the bike is so much more fun to ride.
 
#27 ·
Thankyou guys, thus is great info.

I prefer a torquey bike than a bike with a top end that I can only use legally on a private road.

Will be doing this soon!:D

Sent from my Desire HD using Motorcycle.com Free App
 
#32 ·
stock = 14/38 or 2.71, one tooth less countershaft = 13/38 or 2.923..
difference only about 0.2 of final drive ratio,, enough to have some
effect but not enough to make 1st gear 'useless'..

these are incremental changes, according to personal preference/use..
you could go up 2 teeth rear sprocket for 2.85 [14/40] for a result
midway between stock and 13 tooth countershaft sprocket..

these minor changes would probably be handy for loads
pillions, steep hills and generally a little more access
to engine potential thru the gears, esp in a hurry..
 
#36 · (Edited)
I just picked one up from FutureSport, they ordered it overnight.

Cost me $32.95 (Honda couldn't get any for a couple days).

10-KCZ-13
95-132113

Bird supply Bird food Soil Vegetarian food Small animal food


Edit: Installed. Oh my god. Amazing. Totally different bike!
 
#37 ·
1st gear is basically for getting off the line, esp uphill, with a pillion
or other load [heavy rider, gear etc] thats is basic function..

taking off is more than just dropping the clutch, of course,
but just about anyone can get off the line on cbr250r
ahead of almost any general traffic.. you dont need
a gear change to achieve this function, just practice..
i left a large ducati behind off lights recently after filtering
to the front to find him there in the left lane, both entering
a single lane ahead.. didnt want to get in his way so let her
go.. maybe he wasnt trying, but he certainly roared past
as we eased off after second, staying to the right side
to let him past, which seemed fairly predictable..

a 13 tooth front sprocket would hardly make 1st useless..
the small incremental change would suit its basic functions..
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top