CRF250X setup for perfection !

CRF250X -10 model ,

 

Engine mods:

Athena 280cc kit , FMF Mega power + Q4 exhaust syst parts , Twin Air Powerflow intake kit , Trail Tech heavy flywheel ,  Jetting mods for Scandinavian area , Pulse Racing Fuelscrew , Faction MX Crank vent mods ,  Pink wire mods .

Chassie mods:

CrossPro Aircraft tech alu skid plate / engine protect , CrossPro Radiator protection , Race Tech Gold Valves ( Comp / Rebound / Mid ) + Öhlins 5w race fluid ,  Öhlins TTX rear suspension ( mod: type CRF250R-09 head for fitting X-frame ) , Bark buster handle protectors ,  Trail Tech Vapor instruments ,  Michelin S12 Tyres ,  12T Renthal front sprocket , KTM type 55c Thermostat .

Lighting mods:

HID 35W front light ,  Trail Tech stator + flywheel kit 70w , CRF450X Battery .  

 

***

This combination is close to state of the art !! , and gives you lots of joy out in the woods with mass of power gain and a superb handling suspension.

 

 

Did you do the goldvalves yourself or have a shop do it?  How much difference did it make?

And where are the pics of this little slice if heaven?

what is "KTM type 55c Thermostat"? 

what is "Faction MX Crank vent"? 

couldn't find any info on those

Edited by a c t i v e X

CRF250X -10 model ,

  Trail Tech stator + flywheel kit 70w ,

 

 

Any problems with this system? I'm in need of a new stator possibly a flywheel too and being told the trail tech SR-8201A will fry my bikes electrical system.

Did you do the goldvalves yourself or have a shop do it?  How much difference did it make?

I did the job myself !! , and it made a big difference for me !! , but you need a few hours and a lot of patiance .

Any problems with this system? I'm in need of a new stator possibly a flywheel too and being told the trail tech SR-8201A will fry my bikes electrical system.

No problem at all so fare !! ,  my system is the SR-8202A whit 6141-29 Flywheel and it works perfectly !!

what is "KTM type 55c Thermostat"? 

what is "Faction MX Crank vent"? 

couldn't find any info on those

KTM has a Thermostat that you can install on your bike to prevent any uneven operating temperature , and they usually call it 55 celcius version .

It works very well on any MX / Offroad bikes .

what is "KTM type 55c Thermostat"? 

what is "Faction MX Crank vent"? 

couldn't find any info on those

Manufacture identification here in Sweden are Faction MX Crankcase ventilation kit  ( Yellow hose on red colored connections ) 

, this unit helps the engine to breath better by diverting heated gases away from the airbox !!.

 

And where are the pics of this little slice if heaven?

Have not spent some time taking pictures of the bike yet but appreciate the time of driving higher !!   but it looks on the outside almost like an original CRF250X with some deviations , the big difference is on the inside ! .

What does "big difference on the inside" mean?

What does "big difference on the inside" mean?

 

 

280cc kit etc. Didn't you read the first post?

That looks like a great list of upgrades.  All I have done to date is the air box mod, a loud Mouth air intake, JD jetting and drilled the muffler baffle end.  Next step will be the Athena 280 and a cam change along with a muffler change.

 

My question is on your reasoning for the heavier fly wheel.  Did you find the 280 had too much snap and needed to smooth it out a bit?

did the opposite, lightened the flywheel to get the 280 to rev better

 

My question is on your reasoning for the heavier fly wheel.  Did you find the 280 had too much snap and needed to smooth it out a bit?

 

i did so. the 300cc (297 by Athena) on the CREF300X (HM modded) was too aggressive for me. lots of stalling and too much snap on loose ground on uphils gave me hard time.

installed +8Oz steahley fw and it's amazing. smoothen thing just enough so i don't feel a different in snap, but much better grip both on open gas and on obstacles hit (the stalling went away)

Thanks.  That makes sense for the type of terrain we have around here.  Lots of steep loose rock / large rock hill climbs where you can't carry full momentum.  Often have to pick your way up in a Trials Mode.  I want more snap to be able to throttle lift the front end without much body english but don't want to get out of control for the hill climbs.  I will seriously look at adding the extra flywheel weight with a big bore upgrade.

Does the 297 make a real difference compared to the 280 kit? I want as wide a powerband as possible and still rev if needed. 

Does the 297 make a real difference compared to the 280 kit? I want as wide a powerband as possible and still rev if needed. 

 

The 297CC is a great improve upon the stock 250 i've tested before. i haven't seen a 280CC here to try.

This297CC is stock model for HM (licensed, street legal, etc.)

The power is much more "wide" and noticeable on all range. much more torque (altough it's a big bore)

However it turned the small X to be a bit too aggressive for me (as Battle250x stated, on steep hils, rocks and loose ground, it was a bit "spinner" and tend to stall oftenly. required lots of gas and clutch which is not "smoth riding")

the flywheel did the thing for me. the torque of the 297CC is enough for front lift on almost any gear (14/50 sprockets), while it can lugg on idle without crancking.

best thing for technical rides.

Steahley define the +8oz as "epierienced woods riders". it have also 10 and 13 for even greater traction and/or less aggressive riders

The x cams early intake closing time builds good compression for low end power at 250cc.  Athena targeted 13.1 compression, plus the extra 30cc, equals higher cranking compression at stall speed. Using a wider R cam or aftermarket will help this a bunch, giving the piston/crank some more degrees of running start at the compression event. Less apt to stall. 

Edited by highmarker

The x cams early intake closing time builds good compression for low end power at 250cc.  Athena targeted 13.1 compression, plus the extra 30cc, equals higher cranking compression at stall speed. Using a wider R cam or aftermarket will help this a bunch, giving the piston/crank some more degrees of running start at the compression event. Less apt to stall. 

:thumbsup:

Edited by YHGEORGE

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