cbr250 throttle body for crf250l

I have heard that exchanging the crf250l's throttle body for the cbr250r should increase performance, and i was wondering if it would be better to use an ECU from the cbr, or something like the ejk fuel programmer instead; in combination with the cbr250 TB.

Has anyone done this mod, and if so how much power did you gain?

You would get better bang for your buck by investing in a big bore kit.

I have heard that exchanging the crf250l's throttle body for the cbr250r should increase performance,

Yes. upper rev range. Honda used a smaller throttle body on the CRF-L to improve low-midrange torque, because it is a trail bike.

and i was wondering if it would be better to use an ECU from the cbr, or something like the ejk fuel programmer instead; in combination with the cbr250 TB.

The performance kit includes the CBR250R ECU with the CBR250R throttle body.

EJK is originally for the CBR250R.

Yes. upper rev range. Honda used a smaller throttle body on the CRF-L to improve low-midrange torque, because it is a trail bike.

The performance kit includes the CBR250R ECU with the CBR250R throttle body.

EJK is originally for the CBR250R.

How much low end do you think would be lost? Also what performance kit are you talking about that includes the CBR250R ECU and the throttle body?

Honestly adding a bigger throttle body with out also doing cams is not going to be worthwhile in terms of value for money.

If you want more power start with the EJK, then add exhaust, then if you want more then big bore, then throttle body and cams.

I have played with throttle body mods and by them self do very little to improve performance.

Honestly adding a bigger throttle body with out also doing cams is not going to be worthwhile in terms of value for money.

I have played with throttle body mods and by them self do very little to improve performance.

Here's my thoughts... :rolleyes:

If you want more power start with the EJK, add exhaust and open up the air box snorkle. Toss some gears into the mix too. Then if you want more do a big bore kit with cams and then the throttle body IMO.

Here's my thoughts... :rolleyes:

If you want more power start with the EJK, add exhaust and open up the air box snorkle. Toss some gears into the mix too. Then if you want more do a big bore kit with cams and then the throttle body IMO.

Yes. I agree 100%

Most sensible approach.

Here's my thoughts... :rolleyes:

If you want more power start with the EJK, add exhaust and open up the air box snorkle. Toss some gears into the mix too. Then if you want more do a big bore kit with cams and then the throttle body IMO.

Yeah that sounds like what I will eventually be doing; in good time of course. Also while speaking of big bore kits, does anyone know when they will be released to the general public?

Yeah that sounds like what I will eventually be doing; in good time of course. Also while speaking of big bore kits, does anyone know when they will be released to the general public?

Here a quote from this link.

http://www.thumpertalk.com/topic/1017684-random-power-thoughts/page__st__20

283 cc at 12:1 vs 297 cc at 11:1

What do ya reckon?

If it's close enough probably happy with 283cc

http://www.wiseco.co...013&AppID=46626

http://www.jepistons...f250l_dual.aspx

Here a quote from this link.

http://www.thumperta...ts/page__st__20

I can't believe it's only $230 for that 283cc kit! I wonder how expensive it will be for a 300cc or more kit, but I am extremely tempted with this 283cc deal...

I can't believe it's only $230 for that 283cc kit! I wonder how expensive it will be for a 300cc or more kit, but I am extremely tempted with this 283cc deal...

I think its $230 for the piston alone. I think the lit is around $450 for the total package.

I think its $230 for the piston alone. I think the lit is around $450 for the total package.

Oh yeah you're right.. I knew $200 for a big bore seemed to good to be true

well ..... I might catch a little crap for saying this again but,

Once you have good suspension (Race Tech) This bike with a programmer and gears, exhaust etc .... really screams on the dirt. The stock suspension limits your ability to really see what this bike can do and adding more power will just make it worse.

It really is hard for me to explain and maybe you guys already understand but, without some decent suspension under your butt you will never be satisfied with its performance. The CRF250L in its stock suspended state you just can not push it hard enough to feel its full potential.

One of the best things about this bike is that it does have the geometry to perform very well off road. It really is built off the CRF blueprint but, the stock suspension is set up for cow trails and sight seeing or fire roads etc....

Let me share my evaluation of this little gem we all love ....

The bike is very inexpensive to purchase new.

The bike is very under powered and over geared new.

The bike responds very well to performance mods such as a stage 1 kit and even dropping the gearing to 13/42 with the stage 1 kit will add to your overall top end.

But without upgrading the suspension any extra power mods you do will only make the bike do better wheelies or a faster 1/4 mile time and do nothing for faster lap times or the ability to tackle bigger obstacles out in the real world.

To get back on topic .... Honda made the right choice with a smaller throttle body because ... in my mind it is intended to be a dual purpose machine and the stronger torque at lower rpm's is needed for serious off road.

Now if you are building a supermoto machine ... that is a different story.

I just think suspension should come before a big bore or any other power mods ...

disclaimer:

these are just my drunken thoughts and by no means should be considered as facts ... :p

well ..... I might catch a little crap for saying this again but,

Once you have good suspension (Race Tech) This bike with a programmer and gears, exhaust etc .... really screams on the dirt. The stock suspension limits your ability to really see what this bike can do and adding more power will just make it worse.

It really is hard for me to explain and maybe you guys already understand but, without some decent suspension under your butt you will never be satisfied with its performance. The CRF250L in its stock suspended state you just can not push it hard enough to feel its full potential.

One of the best things about this bike is that it does have the geometry to perform very well off road. It really is built off the CRF blueprint but, the stock suspension is set up for cow trails and sight seeing or fire roads etc....

Let me share my evaluation of this little gem we all love ....

The bike is very inexpensive to purchase new.

The bike is very under powered and over geared new.

The bike responds very well to performance mods such as a stage 1 kit and even dropping the gearing to 13/42 with the stage 1 kit will add to your overall top end.

But without upgrading the suspension any extra power mods you do will only make the bike do better wheelies or a faster 1/4 mile time and do nothing for faster lap times or the ability to tackle bigger obstacles out in the real world.

To get back on topic .... Honda made the right choice with a smaller throttle body because ... in my mind it is intended to be a dual purpose machine and the stronger torque at lower rpm's is needed for serious off road.

Now if you are building a supermoto machine ... that is a different story.

I just think suspension should come before a big bore or any other power mods ...

disclaimer:

these are just my drunken thoughts and by no means should be considered as facts ... :p

I agree with you completely! I was just speaking hypothetically of what mods I could do to give the small 250cc engine more power. I will definitely be redoing the stock suspension to fit my needs after stage 1 upgrade; just curious as to the potential engine mods for this bike.

Now back to the throttle body, you really think giving it a larger throttle body will decrease low end that much? Even with gearing it down, and the big bore kit I would imagine it would have plenty of low end power. Lots more than stock, right?

I agree with you completely! I was just speaking hypothetically of what mods I could do to give the small 250cc engine more power. I will definitely be redoing the stock suspension to fit my needs after stage 1 upgrade; just curious as to the potential engine mods for this bike.

Now back to the throttle body, you really think giving it a larger throttle body will decrease low end that much? Even with gearing it down, and the big bore kit I would imagine it would have plenty of low end power. Lots more than stock, right?

The CBR250R has a larger throttle body and produces less bottom/mid range torque. and don't forget that the CRF has the same engine (that's why I bought it)

I don't claim to know what I am talking about but, after a big bore and cams, valves etc ... a bigger throttle body starts to make sense.

I have done many mods to my bike and I can say for a fact ... if you can hold it pinned around the whole track ... you are one hell of a rider !!!

Horse power makes the bike go faster .... suspension makes the rider do faster lap times ... :ride:

Edited by gnath9

Oh yeah you're right.. I knew $200 for a big bore seemed to good to be true

Even at $450, I reckon that is pretty good value for money.

Have you priced up a new throttle body and ECU? I can't imagine it being cheaper than that, and without the cbr250r cams isn't going to offer much.

Edited by Positron007

Explained nicely and thoroughly by gnath - in a sort of lucid drunk state. :D

However,...

How much low end do you think would be lost?

i think of it more as shifting the main torque and power to a lower part of the rev range.

Also what performance kit are you talking about that includes the CBR250R ECU and the throttle body?

i don't know where the pic of it came from, i have it saved on my computer at home, not here at office, but i think it is somewhere on this forum; you could probably find it by googling the site for keywords kit and "throttle body". Like...

site:www.thumpertalk.com kit "throttle body"

NB here, with reference to the cam together with the CBR throttle body...the kit does include the CBR250R camshaft together with the CBR250R throttle body and CBR250R ECU, and the clutch plate to replace the CRF-L "judder plate" and stiffer clutch springs.

Again, like gnath said, there is no sense in doing it (or even increasing power with a big-bore kit) unless your purpose is street supermoto conversion. And if all you do is ride on the road to get to an MX track, then what he said about suspension is even more applicable.

Let me share my evaluation of this little gem we all love ....

...

The bike responds very well to performance mods such as a stage 1 kit and even dropping the gearing to 13/42 with the stage 1 kit will add to your overall top end.

Making a distinction between performance mods (like bigger throttle body, cams, big-bore kits) and derestricting/undoing limitations that come from the need to comply with emissions and sound regulations. What gnath has done - and i and most others - is simply remove those limitations so the engine can produce the power it is capable of in stock form.

But without upgrading the suspension any extra power mods you do will only make the bike do better wheelies or a faster 1/4 mile time and do nothing for faster lap times or the ability to tackle bigger obstacles out in the real world.

To get back on topic .... Honda made the right choice with a smaller throttle body because ... in my mind it is intended to be a dual purpose machine and the stronger torque at lower rpm's is needed for serious off road.

Dual purpose, trail bike, dual purpose includes commuting and riding around town, and fuel consumption is an issue for many people. It is not a sport bike or competition bike, it is a scrambler like "back in the day", very good for people who ride trails and bad road surfaces, and...hang out with their friends,...general purpose.

Sorry if that all gets too much off the original question about using the CBR throttle body, but i just wanted to...repeat and emphasize what gnath pointed out...in the hope of that perspective getting through to more people, like when more people come to the forum and ask it all again, make it easier to find by searching - although they don't search, but we will have more to copy and paste to make the repeating easier. :):lol:

if you can hold it pinned around the whole track ... you are one hell of a rider !!!

Horse power makes the bike go faster .... suspension makes the rider do faster lap times

And more low-end torque and less revs makes it much easier to get up rocky hills.

Relating to suspension, and maybe this has been addressed, does RaceCrafters add any extra travel or does it just make whats available better?

Hello... I can answer your questions on this.. I have a 2013 CRF250L and I have been experimenting around with different performance upgrades... I have a 2013 CBR250R ECU plugged into my bike right now.  The first thing about it is it's slightly larger in size, but fits into the band just fine.. It also causes my engine light to stay on while riding.  I need to figure out how to over ride that fault...  The fault is generated because I have my O2 sensor unplugged and the canister removed so the sensor on the canister is also unplugged.  What's weird.. Is that my factory ECU has never triggered the fault light with the canister, and O2 unplugged.  I have a couple videos on youtube that show some of my mods.  It's all a process.. I'm ordering a 38mm throttle body.  both the CBR and CRF use the exact same fuel injector, so no need to order that.  I have yet to plug in a programmer, but I will order one and give it a go shortly. 

Hello... I can answer your questions on this.. I have a 2013 CRF250L and I have been experimenting around with different performance upgrades... I have a 2013 CBR250R ECU plugged into my bike right now.  The first thing about it is it's slightly larger in size, but fits into the band just fine.. It also causes my engine light to stay on while riding.  I need to figure out how to over ride that fault...  The fault is generated because I have my O2 sensor unplugged and the canister removed so the sensor on the canister is also unplugged.  What's weird.. Is that my factory ECU has never triggered the fault light with the canister, and O2 unplugged.  I have a couple videos on youtube that show some of my mods.  It's all a process.. I'm ordering a 38mm throttle body.  both the CBR and CRF use the exact same fuel injector, so no need to order that.  I have yet to plug in a programmer, but I will order one and give it a go shortly. 

 

Welcome to the site.  :thumbsup:   Sounds interesting.

 

What other mods have you done to your bike?  I would be interested in what experiments you've done. 

 

:cheers:

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