Changing the front sprocket.

[Jubis]

I know this is an old thread, but it is very useful regardless. I've recently noticed that my 16k km chain is getting on the loose side, and both sprockets are getting a touch pointy. So I've decided that in the next couple of weeks I will be replacing them, and then remembered about the changes you guys here have done with them.

I've decided after a wee bit of reading that -1/+2 will be the way to go, just need to go back to my new shopping playground and get a quote on the sprocket/chain combo, and also find out what their cost to perform the "upgrade" to my bike would be. Otherwise, I'm more than happy to spend an arvo trying it myself


(I also told a workmate who owns a '92 CBR250RR that once I fix the chain/sprockets on my bike I'll kick his ass off the lights hehe)

[jsonder]

Originally Posted by Jubis

(I also told a workmate who owns a '92 CBR250RR that once I fix the chain/sprockets on my bike I'll kick his ass off the lights hehe)

And he let you live? {at least so far, eh?}

[Jubis]

He called bs on it, but when the new gearing is setup I'll keep a camera handy for his jaw dropping.

[MotoMike]

Originally Posted by Jubis

I know this is an old thread, but it is very useful regardless. I've recently noticed that my 16k km chain is getting on the loose side, and both sprockets are getting a touch pointy. So I've decided that in the next couple of weeks I will be replacing them, and then remembered about the changes you guys here have done with them.

I've decided after a wee bit of reading that -1/+2 will be the way to go, just need to go back to my new shopping playground and get a quote on the sprocket/chain combo, and also find out what their cost to perform the "upgrade" to my bike would be. Otherwise, I'm more than happy to spend an arvo trying it myself


(I also told a workmate who owns a '92 CBR250RR that once I fix the chain/sprockets on my bike I'll kick his ass off the lights hehe)

Jubis, I just did the -1 on the front sprocket (staying with the stock chain and rear sprocket), and I'm really liking the improved acceleration, especially through forth, fifth, and sixth gears. Didn't sacrifice too much top end speed either... still able to do a solid 88 MPH on the interstate.

[Jubis]

Okay I finally made some ground trying to find sprockets, there's SO many of them online :\

I pulled the following numbers from the Renthal site, just plugged in the '11 CBR250R:
Front sprocket: 368-520-13P (noticed that Aufitt used a 13GP, which wasn't listed on the Renthal site)
Rear sprocket: 211--520-40P-HA

Tried eBaying the above parts and got pretty much nil, people don't generally list the part numbers in the titles of their listings, which made it somewhat frustrating. They also make a habit of using the same generic image for all their sprockets, so I'm seeing several different sprockets for different bikes all starting with "287" which doesn't help. Tried Googling the part numbers too, to no avail.

Phoned up a place just down the road, these are the prices I was quoted:
368-520-13P @ $24.95
211--520-40P-HA @ $89.95
Gold X-ring 520 chain @ ~$135
+ labour.

That rear sprocket raised my eyebrows, is the price of that one so high because of the HA (Hard Anodised) suffix? I forgot to ask but was there a non-HA equivalent, and what was the longevity comparison? Second to last question would be to Aufitt, what model number was on the rear sprocket you purchased?

Final question also goes to Aufitt (or other Aussies that have changed gearing on their own), did you buy from a distributor or was it through a bike shop that had their own distributors? The former option would seem to be cheaper, however the only Renthal distributor I could find (via Renthals website) was Cassons PL, which are a NSW based company and after a bit of searching didn't have much in the way of 40t sprockets, let alone the 211 I was searching for.

Apologies for the long post

[Aufitt]

Yes the Renthal in the pic that I fitted was from Cassons via my Local honda dealer $24.95.
At the time we couldnt find a compatible rear (bet something fits) part number.

Tyga Thailand do alloy rears for $40
Front sprockets wear 2-3 times as fast as a rear so alloy ok for rear, but would never go less than Renthal quality for the front.

[MotoMike]

SunStar makes steel rear sprockets for the CBR250R in various sizes, and reasonably priced.

[leaf]

Just ordered the JT front sprocket, went with -1. Look forward to feeling the difference.

[stevo585]

I just installed the JT 13T last week. Its worth the price but honestly the bike is still fairly slow. My subaru WRX is faster for sure.

[CBR_Dave]

Originally Posted by stevo585

I just installed the JT 13T last week. Its worth the price but honestly the bike is still fairly slow. My subaru WRX is faster for sure.

No joking? A high performance AWD, boxer engined, "civilianised" rally racer worth what, $40-50K, is faster than a $5k 250cc? Get outta town .

Dave