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2012 crf250r engine mods

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With the  2015 racing season over I am looking to get significantly more horsepower out of my CRF250r.  I am riding the bike to it's limits and am having trouble keeping ahead of the new Yamaha and Kawasaki.  The stock Honda just doesn't have quite enough.  I can spend perhaps 1000.00 to 1250.00 on the motor/exhaust.  Exhaust system?  Cam and springs? High compression piston?  I can only afford 1 major expense.

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I would look into getting a bigger crank with a high compression piston. Exhaust systems don't do much to horsepower they mostly just change the type of power delivery (more bottom end or more top end) I would look into pistons and maybe even head porting/ polishing

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With the  2015 racing season over I am looking to get significantly more horsepower out of my CRF250r.  I am riding the bike to it's limits and am having trouble keeping ahead of the new Yamaha and Kawasaki.  The stock Honda just doesn't have quite enough.  I can spend perhaps 1000.00 to 1250.00 on the motor/exhaust.  Exhaust system?  Cam and springs? High compression piston?  I can only afford 1 major expense.

Search RHC on this forum.

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Look into sending your head out to a company to port and recommend a cam ~ $500-700 then high comp piston ~ $150 Have a person with a dyno sort it out afterwards -200-300

 

Exhaust systems add about as much HP as a sticker on mx bikes. They only matter when they were restrictive to begin with like road going bikes which have things like stringent noise requirements and emissions or motors that were designed as tractors from the start

 

Biggest gains are to be found with head modding (i.e. cams head port and tune)

 

 

Why would Honda leave easy HP on the table , they made the bike, they're not dumb......... they come up with a goals and a price tag then go from there

 

Things like head work are prohibitive for honda and tuning is a matter of environment/mods/bikespecific  

 

 

plus they cant build for race gas...

 

Exhaust systems from AF providers tend to favor peak horsepower and sacrifice low end and rideability

.

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I have a nice used RHC (Ron Hamp) ported race head & camshaft combo coming back from a refresh soon, if that interests you. It'll get you going, for sure.

With the 2015 racing season over I am looking to get significantly more horsepower out of my CRF250r. I am riding the bike to it's limits and am having trouble keeping ahead of the new Yamaha and Kawasaki. The stock Honda just doesn't have quite enough. I can spend perhaps 1000.00 to 1250.00 on the motor/exhaust. Exhaust system? Cam and springs? High compression piston? I can only afford 1 major expense.

Edited by Eddie8v

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Awesome guys!  Sounds like I will be focusing on the head.  I agree with your comment on Honda, but I think it is time for them to step it up on factory HP.  One thing is for sure, the bikes are bullet proof durability which is what Honda engines really stand for.

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Awesome guys!  Sounds like I will be focusing on the head.  I agree with your comment on Honda, but I think it is time for them to step it up on factory HP.  One thing is for sure, the bikes are bullet proof durability which is what Honda engines really stand for.

I would consider eddie8vs head/ cam combo that he is offering up! im sure since its used he wont be asking retail for it and knowing its being refreshed = great for you.

Edited by walent215

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With the  2015 racing season over I am looking to get significantly more horsepower out of my CRF250r.  I am riding the bike to it's limits and am having trouble keeping ahead of the new Yamaha and Kawasaki.  The stock Honda just doesn't have quite enough.  I can spend perhaps 1000.00 to 1250.00 on the motor/exhaust.  Exhaust system?  Cam and springs? High compression piston?  I can only afford 1 major expense.

 

Cams with more duration than stock are a plus for the CRF. Mid to top is improved with a little more duration and not much more lift than stock, and you get to keep the stock valve springs in. Slight loss in low end torque which can be gained back. Stay away from high lift though... it wont help power much on a stock'ish engine, especially when the CRF's choke point is the OEM port spec. Port work helps too... the 2012's dont need much unless you are going full blown race engine. For now just raise the roof a little, cut down the pertrusion of intake guides, de-shroud the valves in the combustion chamber and clean up all the casting flash. Thats a basic port mod you can easily do or have done. Real race engines I build have drastically different porting than that but those little things you can do yourself and wont hurt power anywhere, all gains. High compression piston is another plus. No more than 14:1.... JE's 13:8.1 is a great choice. Deck head around .005" to .008", you will need a machinist for this or a local shop, this will bring the low end torque back and help top as well. A pipe... Bills and Rocket are excellent choices for the price and will make more power than stock. A simple ECU flash from a reputable shop. Do those little things and you wont be diassapointed. If you have more questions just let me know. The CRF250 is a great platform... just needs some very simple and minor tweaks to make her a very peppy steed.

 

-Matt

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With the  2015 racing season over I am looking to get significantly more horsepower out of my CRF250r.  I am riding the bike to it's limits and am having trouble keeping ahead of the new Yamaha and Kawasaki.  The stock Honda just doesn't have quite enough.  I can spend perhaps 1000.00 to 1250.00 on the motor/exhaust.  Exhaust system?  Cam and springs? High compression piston?  I can only afford 1 major expense.

 

I would sell the Honda and put the extra cash you would spend modding the honda into a Yamaha, or Kawi.

They're both better race bikes off the show room floor than $1200 can get you with the Honda.

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