changing sprocket for a zx2r

[GForce]

hi guys, i am going to change my rear sprocket because it is time and i was wondering if anyone here changed their standard to larger sprocket.

i want more acceleration because i find the zx2r are abit sluggish in low rpm compared to my brothers cbr250rr.

ok my question is what is the standard size rear sprocket and how much have u gone up by. how does this affect the top end and 0-100?

thanks

[Kishy]

This document tells you everything you need to know about the ZX-2R..
Do a search for "sprocket", check index or go straight to pages 90-92

http://ninja250.kingston.net/~jeb/Kawas ... %20FAQ.pdf

[Neka79]

mate approx ratio of 1:3

most bikes have like a 14;42 type ratio, so going up 3 on the back is the same as dropping one on the front...i was always told dont drop teeth (wears sprockets quicker) but to add teeeth...but sumtimes u cant get the right pitch combo in the teeth combo u want...

heres my tips-
go with standard pitch (525 or 530 id guess??)
go STEEL sprockets (alloy ones dont last...look pretty tho)
go chain & both sprockets together, otherwise ur just gunna stuff em quick...

[GForce]

thanks for the info kishy but i dunno if that is talking about the zx2r we get here in aust. the american ones are different and dunno if they have the same sprocket as the zx2r.

i was thinking going up 3 teeth on the rear sprocket but i dunno how that will affect the acceleration. i just want to know what the gears would be like. eg how many gears i have to go through to get to 100

[Kishy]

Sorry bro

Should still provide info on effect changing of sprockets will have on the bike..

[Neka79]

thanks for the info kishy but i dunno if that is talking about the zx2r we get here in aust. the american ones are different and dunno if they have the same sprocket as the zx2r.

i was thinking going up 3 teeth on the rear sprocket but i dunno how that will affect the acceleration. i just want to know what the gears would be like. eg how many gears i have to go through to get to 100

ok mate..if i were in the mood to think and i knew the original sprockets, i could work out the change...

going up 3 on the back would mean u will run out of revs a lil quicker, u will accel quicker and sacrifice top speed...
i would expect maybe at 100kph ur speedo will be out by approx 10-15% and ur bike will be reving 15% higher approx in the same gear...

this is a guess, but if u can find the original ratio, i have a gear calculator (used for stunt bikers) which may help..

[GForce]

thanks for that neka79. i figured out that my zx2r would be sitting at around 8500rpm when doing 100 in 6th gear (approx the same as the cbr). that i dont mind coz i dont go on the highway often.
i think i would now need to finish 2nd and into abit of 3rd gear before i reach 100. i will just go 3 up on the rear. ill post up the results when i get it installed with the chain.

thanks again

[Neka79]

mate..as a matter of interest...my 900 does 134kph in 1st gear....but at abt 12000rpm.....
it does 100kph in 2nd at abt 9000rpm......but in 6th, at a steady 110kph on freeway its at abt 3300rpm...

my point is, dont change ur sprockets if u want good fuel mileage....

what it will give u is

*lighter front end under power (wheelies)
* better acceleration
*better exit of corners based on accel
* higher fuel bill

[GForce]

i do alot more city riding than in the highways. when i am doing 60 in 6th, my rev is 4000rpm and which i find it sluggish. acceleration is not as good compared to my bro cbr. i find acceleration makes the bike more enjoyable to ride around the city and thus i want to change the sprocket.

[Neka79]

i do alot more city riding than in the highways. when i am doing 60 in 6th, my rev is 4000rpm and which i find it sluggish. acceleration is not as good compared to my bro cbr. i find acceleration makes the bike more enjoyable to ride around the city and thus i want to change the sprocket.

more importantly..u and ur bro ride 2 lil bikes around adelaide city?? why havent i met u yet??
wot colour bike u got??? details mate...how long u had it??

[zbeast]

Unless the 2R is doing 10k rpm it doesn't want to go anywhere in a hurry. Leave it in 4th if you're only doing 60. I know mine would do 190 in 5th on the limiter so a couple of teeth on the rear should bring 6th back to about the equivalent of 5th which is plenty fast enough. Be careful that you don't make first redundant though...gear changes cost time on acceleration so you may just find that all you're doing is lifting the front wheel easier and changing gears earlier while your brother rides away. Better off practising your launch technique with the standard gearing. 10k rpm and slip the clutch a bit should see you outta there much faster. A guy who lives around my area had a CBR when I had my ZXR and I never had a problem beating him in the traffic light drags. Of course it was a different story when he traded up to an R1 but it was still fun having a go.

[GForce]

ive got a green zx2r (unique green with gold in it) and my bro has a cbr250rr aussie delievered. we should all meet up sometime.

as zbeast said before, 5th gear hits the speed limiter so whats the point of having a 6th? i dont do highway riding often so i think abit more acceleration through all the gears will make me very happy. as long as i can still hit around the 180 mark with the new sprocket, i will be happy

[Neka79]

ive got a green zx2r (unique green with gold in it) and my bro has a cbr250rr aussie delievered. we should all meet up sometime.

as zbeast said before, 5th gear hits the speed limiter so whats the point of having a 6th? i dont do highway riding often so i think abit more acceleration through all the gears will make me very happy. as long as i can still hit around the 180 mark with the new sprocket, i will be happy

6th gear is an overdrive...its not meant to give u more speed... in sum cases 6th u may lose a km/h or 2... 5th is a much higher gear, and ussually the fastest gear uve got...

[GForce]

ohh i see. im such a noobie when it comes to bikes.
well ive asked around for the rear sprocket and it will cost me around 50 bucks. now the only question is whether to go up 2 or 3 teeth?? how much will these affect my top speed? eg going 2 teeth up, might lose 5km/h

if someone could clarify this for me, i would be very thankful.

[Neka79]

ohh i see. im such a noobie when it comes to bikes.
well ive asked around for the rear sprocket and it will cost me around 50 bucks. now the only question is whether to go up 2 or 3 teeth?? how much will these affect my top speed? eg going 2 teeth up, might lose 5km/h

if someone could clarify this for me, i would be very thankful.

hmm id go 3...hell i went 3 on my 900 (mainly for other reasons tho)...

front sprocket- approx $15
rear sprocket -$50
chain - $130-200 depending

its a 250...u DONT HAVE top speed worth worrying about...u might as well use low down torque/accel....i dunno how many km/h i lost, cos i rarely get over 250kph- even on the track!!