[cyanide]

LOL, true. But still fun nonetheless.

Anyways, I am branching out the info and questions into other threads since the OP is content with bolt-on mods, while our discussions seem to have gone way beyond that. Looking forward to discussion some cool stuff with you guys.

 

[Brian]

lol...sorry. I overreacted and started it all..
but we're over it...even best friends and brothers have arguments..
everything's cool.

Guys i need another bit of advice...me being a doctor and stuff,i have to go to the hospital everyday on this machine..and though i want to install an aft-market exhaust,i dont want something tooooo loud,for obvious reasons.

what exhaust should i go for,that wont be race-bike loud?
even the dirt bike sound doesnt work for me..

is there an exhaust that'll augment the natural exhaust sound without being a screaming devil??? i've checked out exhaust videos on YT,but i cant really gauge how loud an exhaust'll be in real life from its videos..

DR. check this out, in case you missed it.
http://www.cbr250.net/forum/cbr250-parts-accessories/1288-yoshi-two-bros-6.html

 

[drankurbaruah]

DR. check this out, in case you missed it.
http://www.cbr250.net/forum/cbr250-parts-accessories/1288-yoshi-two-bros-6.html

hey!! thanks a lot man....
\m/

 

[drankurbaruah]

LOL, true. But still fun nonetheless.

Anyways, I am branching out the info and questions into other threads since the OP is content with bolt-on mods, while our discussions seem to have gone way beyond that. Looking forward to discussion some cool stuff with you guys.

thanks man...am starting with simple things that are hassle free and dont offer me any scope to mess up the bike..
i hope i can make some useful posts after i get more miles on the odo and acquire more tech-knowledge by reading up on it.
happy riding my friend.

 

[PolyOlefin]

the only thing worse than a racist, is the guy thats still so sensitive as to be offended by them...

I agree Drank overreacted, but this has to be the most idiotic post on this forum.

Really? Being offended by racism is WORSE than being a racist? I may be wrong but I'm going to venture a guess that you're white and have never experienced vitriolic, in-your-face racism like I have.

But oh, yeah, forget about the ignorance and bigotry that led to such hateful words, what's MY problem for being offended?

I suppose if I called your mother a ***** and you got upset, you are a worse person than I am because you let it get to you.

Dumb.

 

[drankurbaruah]

I agree Drank overreacted, but this has to be the most idiotic post on this forum.

Really? Being offended by racism is WORSE than being a racist? I may be wrong but I'm going to venture a guess that you're white and have never experienced vitriolic, in-your-face racism like I have.

But oh, yeah, forget about the ignorance and bigotry that led to such hateful words, what's MY problem for being offended?

I suppose if I called your mother a ***** and you got upset, you are a worse person than I am because you let it get to you.

Dumb.

let it be my friend...its obvious that his comment was insulting and that i too over reacted..its ok..it happens sometimes,and plus there's enough hate in the world already.
lets discuss bikes man...
and i hope you are enjoying your CBR 250R..
Happy riding mate!!

 

[CNI Dawg]

Can you do an engine swap to a CFR250R ?
Or rebuild the top end of the CBR with CFR parts ?
CFR has got 13.2:1 compression (vs the CBR 10.7:1)
And uses a 46mm throttle body (vs a 38mm CBR throttle body)
I bet the head's intake ports are larger for the increased throttle body size (as well as exhaust ports)
Bore & stroke is a bit different tho so just using a top end from a CFR might not work
CFR 76.8mm x 53.8mm
CBR 76.0mm x 55.0mm

if you swapped the engines the CFR transmission is 5 speeds vs CBR 6 speeds

(info taken from bikez.com - dunno how accurate it is)

 

[BBRMotosports]

What the heck is a CFR? are you talking a CRF mx Bike?

 

[CNI Dawg]

Kinda makes me wish they still made the Honda Hornet 250 & imported it to the USA
In line 4 , 40HP @ 14,000RPM, 17.7 ft/lb @ 10,000RPM. 332lb

 

[CNI Dawg]

What the heck is a CFR? are you talking a CRF mx Bike?

Oops....CRF250R

My bad

All the letters were there just not in the right positions - LOL !

_______________________________________
BTW here's a google link for the CFR250R
http://motorcycle2012.com/honda-cfr250r-spec-2012.htm

Thought if you read it on the internet it MUST be true

 

[BBRMotosports]

The problem with the CRF motor is that being 5 speed is no good for the street, CRF motors are good for about 40 hours then they need a top end. 80 hours they need valves unless you use somthing like kibble white. As far as swaping parts the engines are different. The CRF uses a uni cam. So the head is different, valve size is different, and it only has one cam. I have a CRF450 now and all the new 4 stroke MX bikes are maintinance hogs. Every time you ride " a good practice session or race" the oil needs to be changed. So all in all that idea gets the AX lol.

 

[Soul Searcher]

Decisions, Decisions, Decisions.

Looking for more HP? A question to ask yourself. Are you using the HP, that the cbr's engine is capable of producing, in the most efficient manner? More HP would be great. But then their is such a high cost for each HP gained.

Something to think about. Increase the transfer of HP to the rear wheel in a more efficient manner.

But the first thing you have to choose is what do you want the cbr to do. A red light racer, fastest to the 100 ft mark, faster in the 1/4 mile, to exceed the 100 mph mark. Also on the other hand. Faster crusing speed with lower engine rpm's, faster commuter speed, or how about the most gas mileage.

Once you decide on what you want the cbr to do, then you will know in which direction to proceed.

As with most motor vehicles, you can only have it be average in all functions, or have it excell at one function. This is a choice, only you can decide.
.

 

[Redline]

32 BHP?

Sure it's possible.

Buy a Ninja 650, put CBR stickers on it and ride it around at 3500rpm?

 

[rocketscience3]

Since we are talking about voiding the Honda warranty anyway, why not find a used motor from a bigger bike and wedge it in there. I'm sure it wouldn't be easy to do but maybe it would be easier than taking the engine apart or creating parts that don't yet exist.

 

[Soul Searcher]

Or, for the small sum of $35,000 plus shipping, a MotoGP3 Honda.

 

[Kurlon]

Or, for the small sum of $35,000 plus shipping, a MotoGP3 Honda.

Moto 3 engines cannot cost more than 12,000 Euro as per MotoGP regulations. 'Optional Parts' or other silliness cannot be used to get around that price cap. You want a Moto 3 engine, thats what it'll cost. At the current exchange rate that's roughly $15,750.

 

[superanium]

A turbo charger would lend itself well to this motor. The compression and valve timing are tame. The turbo could bolt directly to the head so efficiency and spool speed would be fantastic. With the right cam timing and ignition timing mapping this bike could make great horsepower and low end grunt. If final drive was made tall enough, then fuel mileage would be better than stock as well, because turbo engines are more efficient.

 

[Soul Searcher]

The Whole Package!!!

Moto 3 engines cannot cost more than 12,000 Euro as per MotoGP regulations. 'Optional Parts' or other silliness cannot be used to get around that price cap. You want a Moto 3 engine, thats what it'll cost. At the current exchange rate that's roughly $15,750.

Instead of reengineering the cbr. It would cost less to purchase the Complete Motorcycle. Information below is courtsey of motorcycle-usa.com. link to website :

http://www.motorcycle-usa.com/791/10188/Motorcycle-Article/Honda-

Former 500 GP world champion Alex Criville will complete demo laps on the
NSF250R tomorrow and on Sunday before the MotoGP race in Barcelona.
Sales of the new road racing motorcycle are planned to start in December
2011. Initial MSRP is 23,600 Euros (U.S. $34,070).

 

[Petrolsniffer21]

Only 10 years later.
I've started building a fairly trick cbr250r powered trackbike.
Chassis is a Cagiva mito. Bridgestone r11 120 rear tyre, moto3 Bridgestone 90 front.

Full custom underseat exhaust system.
38mm Keihin fcr flatslide carb
Going to delete the balance shaft as they are known to fail at higher rpm.
Compression will be bumped as high as possible. Realistically around 12:1 on the standard piston while retaining some reliability. Pistons are expensive so I'll do some more bargain hunting for a forged one
Full head port and flow.
Rpm will be bumped to around 12k as they have been known to go there reliably
Suspension will be modified standard units.

This is a budget build to large degree. I own an engineering firm so most of the work will be done by my guys for cheap.

Nsf250 fairings and standard brakes with sbs ceramic pads.

 

[Petrolsniffer21]

I'm aiming for 35hp.
We had a standard one with just a ported, flowed and skimmed head make 27hp.
Standard fueling unit.