cbr250rr modifications

**HDTboy** · 30th April 2010, 09:24

I posted a guide to modifying these bikes on here about 5 years ago. SEARCH.
@RROF: Flag the 400 motor, get a 2T 500. But then you're still stuck with a 20 year old chassis and brakes designed for slowing down a sewing machine motor.
@VTEC: You may be getting confused between cam timing and ignition timing, altering either may give you a power increase, or may decrease power or destroy the engine if you get it very wrong. The process is called tuning, and having a dyno makes it a less difficult job.

**.produKt** · 30th April 2010, 09:47

Originally Posted by ac3_snow

Hey mate check this out re your airbox
http://www.cbr250.com/cbr250/forum/t...TOPIC_ID=26849

all Iv done is replace my filter with foam (uni foam from most mtrbike shops-remember foam oil too) and noticed a slight improvement (then again old paper 1 was filthy). didnt reali have the time or funds to get right in there with new jets and all.
Interesting looking at the dyno sheet someone showed previously tho makes me wanna strip my carbs and clean etc....
I have heard that the headers where sumwhat restricitve too, but for the cost of new ones is it reali worth it?
that cbr250.com site has some wicked tech posts and tips (saved me when i stripped my brakes down) shows you how to do fork oil and stiffen them up etc..

Ignore the angry buggers above. I couldn't find that so called guide and it's an offence to mislead about engine capacity etc etc blah

"I have heard that the headers where sumwhat restricitve too, but for the cost of new ones is it reali worth it?" I plan on doing just that, Buying an entire exhaust system from RM and i will be doing a Dyno test video before and after

**lankyman** · 30th April 2010, 12:20

Originally Posted by BladeBoy

Is there any modifications a can do to my mc22 to give it more power? if i opened up the airbox slightly and put air intake into the box would it do anything or just make it run to lean? i think they squeeze all the power they can out of these little motors but there must be something else i can do. its got a smaller front sprocket and an aftermarket can already.

Upgarde....I suggest the NC30 VFR400. Handles like an MC22 with nearly twice the pep

**HDTboy** · 1st May 2010, 17:45

Originally Posted by .produKt

Ignore the angry buggers above.

Fuck you, don't be a lazy cunt. Search

**.produKt** · 1st May 2010, 18:36

Yay! A single page thread with a dead primary URL

...

**ac3_snow** · 25th June 2010, 22:36

lol hopefully this so called guide will work this time
http://motorbikecity.com/cbr250/foru...TOPIC_ID=26849

**.produKt** · 27th June 2010, 22:26

Originally Posted by ac3_snow

lol hopefully this so called guide will work this time
http://motorbikecity.com/cbr250/foru...TOPIC_ID=26849

Yea did work. But all images are moved and\or deleted, so nohope of doing it myself.

I have now got a shiny new rear can and headers for the cbr. Oversized and sounds great.
Needs to be tuned tho. theres a horrid deadspot around 8k rpm which seams less a dead spot when the bike is thoroughly warm.
Powerband rpm's (12.000 - 14,500) seems to charge a lot harder but that could be a perseption thing due to the dead spot.

**The Pastor** · 28th June 2010, 11:11

Originally Posted by .produKt

Yea did work. But all images are moved and\or deleted, so nohope of doing it myself.

I have now got a shiny new rear can and headers for the cbr. Oversized and sounds great.
Needs to be tuned tho. theres a horrid deadspot around 8k rpm which seams less a dead spot when the bike is thoroughly warm.
Powerband rpm's (12.000 - 14,500) seems to charge a lot harder but that could be a perseption thing due to the dead spot.

(just keep it above 8krpm)

**.produKt** · 28th June 2010, 11:25

Heh. A smartarsed yet correct reply :P

Quick off topic question. Did you notice that the larger exhaust diameter fouls the movement of the rear brake lever?

**The Pastor** · 28th June 2010, 11:34

Originally Posted by .produKt

Heh. A smartarsed yet correct reply :P

Quick off topic question. Did you notice that the larger exhaust diameter fouls the movement of the rear brake lever?

no, it was custom made so everything should be working great, post up a picture?

Also check the bolts for the slipon are not touching the swingarm, they will gorge it a bit. hard to describe

**.produKt** · 28th June 2010, 12:02

Will post up a pic tonight when i can borrow a Camera.

Bolts for the slip-on are a-ok. Guys who mounted it made sure the nut and bolt of the clamp are rotated to the top of the slipon section. They didn't notice the brake lever movement foul tho =\, which i find particularly annoying.
edit: Fouls to roughly 1/4 braking effort. Annoyied but not concerned as exhaust moves a bit with force on the brakes so can get more out of it if need be