CRF250R Race Bike Build

Spuder155
Hi guys need some advice.

At the moment I have a bone stock (engine wise) 2015 crf250r and have big plans of building a race bike out of it.
I have owned the bike from new and it currently has about 65 hours on it. Valves have been checked frequently but hasn't had a top end yet.

These are the mods I was planning to make:

- JP High Comp Piston
- Hotcams Stage 2 Cam
- Pro-Circuit T-6 System
- Tokyo Mods Remapped Ignition
- Tokyo Mods Engine Breather Kit
Also plan to run it on 100 octane AV Gas

Would all this work?
Is there anything else I need?
What would be the best compression ratio?
What would be the best crank to put in it?

Here it is


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ianhendry46
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ianhendry46 9/20/2016 8:39pm
9/20/2016 8:39pm
OEM crank with Carrillo rod, matched to a cosworth high comp piston. If I was you, I'd go with the FMF single instead of the PC dual. Supercross 14, we made more power with the FMF single than the PC dual. Have the ignition mapped and be very specific and detailed when telling them what you are putting into the bike.
It would also be worth it to bump up your valve spring strength. And last but not least, pull the backfire screen out.
CarlinoJoeVideo
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CarlinoJoeVideo 9/20/2016 10:53pm
9/20/2016 10:53pm
If you are going to do all that work I'd have the engine dyno'd and mapping done to take advantage of all the mods. That would be the best bang for your buck.
Spuder155 9/21/2016 12:18am
9/21/2016 12:18am
ianhendry46 wrote:
OEM crank with Carrillo rod, matched to a cosworth high comp piston. If I was you, I'd go with the FMF single instead of the PC...
OEM crank with Carrillo rod, matched to a cosworth high comp piston. If I was you, I'd go with the FMF single instead of the PC dual. Supercross 14, we made more power with the FMF single than the PC dual. Have the ignition mapped and be very specific and detailed when telling them what you are putting into the bike.
It would also be worth it to bump up your valve spring strength. And last but not least, pull the backfire screen out.
Okay thanks. Will look into that crank.
I have had my backfire screen out for about 6 months now and am also running a high flow filter.
Spuder155 9/21/2016 12:20am
9/21/2016 12:20am
CarlinoJoeVideo wrote:
If you are going to do all that work I'd have the engine dyno'd and mapping done to take advantage of all the mods. That would...
If you are going to do all that work I'd have the engine dyno'd and mapping done to take advantage of all the mods. That would be the best bang for your buck.
There isn't anyone local who has a dino but if I do travel to Perth I will definitely put it on one. Smile

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mx621
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mx621 9/21/2016 5:40pm
9/21/2016 5:40pm Edited Date/Time 9/21/2016 5:42pm
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for high rpm/high hp engines. It's designed for air planes that run 3-4000 rpm for hours at a time.
JkopMx
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JkopMx 9/21/2016 8:32pm
9/21/2016 8:32pm
Second the proven Moto mod Kit . will rip for sure . have ridden 10+ proven motors and I can definetly say its "proven "
Spuder155 9/22/2016 5:13am
9/22/2016 5:13am
mx621 wrote:
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for...
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for high rpm/high hp engines. It's designed for air planes that run 3-4000 rpm for hours at a time.
I would totally go for that Proven Moto package however I don't have that much to spend. What fuel would you recommend I use. I can't afford race gas. Could I run 98 octane with some octane booster?
mxb2
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mxb2 9/22/2016 6:23am
9/22/2016 6:23am
mx621 wrote:
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for...
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for high rpm/high hp engines. It's designed for air planes that run 3-4000 rpm for hours at a time.
Spuder155 wrote:
I would totally go for that Proven Moto package however I don't have that much to spend. What fuel would you recommend I use. I can't...
I would totally go for that Proven Moto package however I don't have that much to spend. What fuel would you recommend I use. I can't afford race gas. Could I run 98 octane with some octane booster?
If you can afford 2-4k in motors mods, you can afford race fuel. If you cant afford the fuel ,your wasting money on the mods. Like buying a Cadillac with cloth interior, doesn't make sense.
Spuder155 9/22/2016 6:45am
9/22/2016 6:45am
mx621 wrote:
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for...
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for high rpm/high hp engines. It's designed for air planes that run 3-4000 rpm for hours at a time.
Spuder155 wrote:
I would totally go for that Proven Moto package however I don't have that much to spend. What fuel would you recommend I use. I can't...
I would totally go for that Proven Moto package however I don't have that much to spend. What fuel would you recommend I use. I can't afford race gas. Could I run 98 octane with some octane booster?
mxb2 wrote:
If you can afford 2-4k in motors mods, you can afford race fuel. If you cant afford the fuel ,your wasting money on the mods. Like...
If you can afford 2-4k in motors mods, you can afford race fuel. If you cant afford the fuel ,your wasting money on the mods. Like buying a Cadillac with cloth interior, doesn't make sense.
Geez man I'm only 16 and I actually have a part time job to fund my racing. Just can't afford to throw cash at it, you know. Dry
Spuder155 9/22/2016 6:47am
9/22/2016 6:47am
I'm just trying to find the most cost effective way to increase hp.
mxb2
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mxb2 9/22/2016 7:04am
9/22/2016 7:04am
Spuder155 wrote:
I'm just trying to find the most cost effective way to increase hp.
Vortex ecu,and a pipe, suspension,fresh tires.good fuel. Mx isn't cheap. Modded motors aren't either, and are higher wear. Like i said if you cant afford good fuel,you can't afford to maintain a modded bike.
Spuder155 9/22/2016 7:12am
9/22/2016 7:12am
mxb2 wrote:
Vortex ecu,and a pipe, suspension,fresh tires.good fuel. Mx isn't cheap. Modded motors aren't either, and are higher wear. Like i said if you cant afford good...
Vortex ecu,and a pipe, suspension,fresh tires.good fuel. Mx isn't cheap. Modded motors aren't either, and are higher wear. Like i said if you cant afford good fuel,you can't afford to maintain a modded bike.
Okay thanks man for the input.
mxb2
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mxb2 9/22/2016 7:21am
9/22/2016 7:21am
mxb2 wrote:
Vortex ecu,and a pipe, suspension,fresh tires.good fuel. Mx isn't cheap. Modded motors aren't either, and are higher wear. Like i said if you cant afford good...
Vortex ecu,and a pipe, suspension,fresh tires.good fuel. Mx isn't cheap. Modded motors aren't either, and are higher wear. Like i said if you cant afford good fuel,you can't afford to maintain a modded bike.
Spuder155 wrote:
Okay thanks man for the input.
Is your suspension fresh?, Set up for you,springs,valved sag?
mx621
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mx621 9/22/2016 7:33am
9/22/2016 7:33am
mxb2 wrote:
Is your suspension fresh?, Set up for you,springs,valved sag?
If none of this is done already motor mods are a waste of money. Are u an A,B,C rider?
mxb2
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mxb2 9/22/2016 7:40am
9/22/2016 7:40am
mxb2 wrote:
Is your suspension fresh?, Set up for you,springs,valved sag?
mx621 wrote:
If none of this is done already motor mods are a waste of money. Are u an A,B,C rider?
Exactly.
Spuder155 9/22/2016 8:03am
9/22/2016 8:03am
Yes suspension is fresh. Have a set of kyb psf 2 with about 15 hours on them. Rear sag is set. Front hasn't been revalved but will have them done at the end of the season. Have played with the clickers though to best suit myself.

I would class myself as a B rider.
mxb2
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mxb2 9/22/2016 8:37am
9/22/2016 8:37am
Spuder155 wrote:
Yes suspension is fresh. Have a set of kyb psf 2 with about 15 hours on them. Rear sag is set. Front hasn't been revalved but...
Yes suspension is fresh. Have a set of kyb psf 2 with about 15 hours on them. Rear sag is set. Front hasn't been revalved but will have them done at the end of the season. Have played with the clickers though to best suit myself.

I would class myself as a B rider.
Spring rate correct?,no revalve? Unless your killing the b class, motor mod $$, your wasting. Use it for a riding school. I bet a A rider could win on a stock well prepped bike. Keep the bike reliable. If your on a budget,you shdnt be modding a 250f.
SeaClassExpert 9/22/2016 8:50am
9/22/2016 8:50am
mx621 wrote:
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for...
Do the provenmoto.com head/fmf single/cam/tune package deal along with the carillo long rod setup. Thing will rip!!! And don't run av gas. It's not designed for high rpm/high hp engines. It's designed for air planes that run 3-4000 rpm for hours at a time.
Do you honestly believe this? Aviation gas isn't 'Designed' exclusively for airplanes. Not to mention that 'Aviation Gas' is a ridiculous catch all term that doesnt incorporate Lead Content and Octane level.

OP, you're fine running Av Gas, so long as you tell them the octane and lead levels. Its perfectly safe for dirtbikes.

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mx621
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mx621 9/22/2016 1:20pm
9/22/2016 1:20pm
SeaClassExpert wrote:
Do you honestly believe this? Aviation gas isn't 'Designed' exclusively for airplanes. Not to mention that 'Aviation Gas' is a ridiculous catch all term that doesnt...
Do you honestly believe this? Aviation gas isn't 'Designed' exclusively for airplanes. Not to mention that 'Aviation Gas' is a ridiculous catch all term that doesnt incorporate Lead Content and Octane level.

OP, you're fine running Av Gas, so long as you tell them the octane and lead levels. Its perfectly safe for dirtbikes.
I'm sure it's fine on a stock 250f. But I would not run it on a high comp 250f or any other engine that requires race fuel for that matter.

http://www.rockettbrand.com/downloads/tech_bulletins/Tech-Racing%20Gaso…
CarlinoJoeVideo
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CarlinoJoeVideo 9/22/2016 9:13pm
9/22/2016 9:13pm
I agree with these guys. If you can afford the gas don't do engine work. Once you do high comp piston and head work, you really need to service your engine every 25hours. So that's a bigger cost as well.

Revalve your suspension, Vortex Ecu, full exhaust will be way better bang for your buck.
Jrewing
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Jrewing 9/23/2016 5:57am
9/23/2016 5:57am
Buy a 250 2 stroke. Lighter faster. All those parts are expensive. It's a slow bike stock. How does it have psf-2 if it's a 250?
Spuder155 9/23/2016 6:31am
9/23/2016 6:31am
Jrewing wrote:
Buy a 250 2 stroke. Lighter faster. All those parts are expensive. It's a slow bike stock. How does it have psf-2 if it's a 250?
They are from my Dads 450 that he doesn't ride often.
snape99
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snape99 9/23/2016 6:42am
9/23/2016 6:42am
Sell the 4 stroke and get a 250 2 stroke. And spend the money on suspension. Way cheaper in the long run
Matt Fisher 9/23/2016 7:44am
9/23/2016 7:44am
The AvGas will work fine, though as pointed out it's not quite up to par with race fuels from a pure performance standpoint (hey- you get what you pay for). It it, however, so much better than pump swill in the US it's not funny. Don't know how pump fuel from Down Under compares to

I'd 100% agree that at this point in time in your life if you can't afford to run race fuel you probably shouldn't mod the motor out. It'll cost way more to build it that way and now everything will wear out that much quicker since it's under more stress from producing more power, likely at a higher average RPM. Some basic mods as you replace the worn stock components is pretty easy to justify...

Fresh suspension and tires combined with lots of seat time will beat out a modded motor 9 times out of 10. Even better if you have a professional rider coaching you; maybe that fits into the budget without the trick motor?

I don't think anyone's being negative about modding the motor, we all like the really trick stuff, and the "moarpower" bug runs rampant though most of the veins here. But since you are on a tight budget, you need to spend what money you have on whatever gets you the biggest lap time improvement, not what sounds cool.
JWACK
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JWACK 9/23/2016 4:33pm
9/23/2016 4:33pm
Crf 250s take a licking and keep on ticking with mods. I've owned 3 with good luck on all of them. I bumped the compression on mine. Stage 2 cam. Exhaust. good valve springs. Put over 100 hours on it before rebuild and never needed to adjust the valves. Best bang for the buck mod would be going up a tooth on the rear if you feel you need a bit more oomph.
JWACK
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JWACK 9/23/2016 4:49pm
9/23/2016 4:49pm Edited Date/Time 9/23/2016 4:51pm
Spuder155 wrote:
I would totally go for that Proven Moto package however I don't have that much to spend. What fuel would you recommend I use. I can't...
I would totally go for that Proven Moto package however I don't have that much to spend. What fuel would you recommend I use. I can't afford race gas. Could I run 98 octane with some octane booster?
mxb2 wrote:
If you can afford 2-4k in motors mods, you can afford race fuel. If you cant afford the fuel ,your wasting money on the mods. Like...
If you can afford 2-4k in motors mods, you can afford race fuel. If you cant afford the fuel ,your wasting money on the mods. Like buying a Cadillac with cloth interior, doesn't make sense.
Spuder155 wrote:
Geez man I'm only 16 and I actually have a part time job to fund my racing. Just can't afford to throw cash at it, you...
Geez man I'm only 16 and I actually have a part time job to fund my racing. Just can't afford to throw cash at it, you know. Dry
Good on you for having a job and paying for your racing.! I will say that if you can invest in anything on your dirt scooter. Do the suspension. It will blow your mind the first time you haul ass into a rough corner and it just soaks it all up. You can literally be seconds per lap faster instantly with good suspension.

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