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Mike Coe's jetting specs for high altitude crf 230?

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I recently purchased a 2005 crf 230. The bike seems to run fine but it is hard to start cold. I have to keep revving it for 2 to 3 minutes before I can ride it. 

I've looked up Mike coe's jetting but it seems everyone rides close to sea level. My riding areas range from 5,000 to 9,000 feet above sea level. I live in south east Idaho. Temp range is 40 to 90 F. My current jetting is as follows

Main 120

Pilot 42S (what does the S mean?)

Needle in the 3rd position (Middle position... this is the stock 03-05 needle)

Fuel screw was 2.5 turns out.

 

Any recommendations on what I should change? The bike just seems hard to start when cold. 

Also how do you guys adjust the fuel screw when the bike is running?? I can't get to the screw without burning myself!

 

Any help would be appreciated.

 

Austin

 

 

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Sorry I forgot to mention that my bike is stock except that the exhaust is uncorked and the air box snorkel is removed.

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The obvious culprit here is your pilot jet. This is the stock one and will be too lean for an uncorked bike. Try a 45 pilot with the fuel screw at 2 turns out. This will be very close and fix your cold idling problem. I reckon your bike will also benefit by putting the clip on the fourth position of the needle but this is only from my experience for a better mid and will not affect the idle. Good luck!

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Would a 45 pilot be too rich for my elevation? I guess I could give it a try.

Anybody else ride similar elevations like me or have an opinion on what I should change.

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Would a 45 pilot be too rich for my elevation? I guess I could give it a try.

Anybody else ride similar elevations like me or have an opinion on what I should change.

 

You may find the 45 to be just a tad rich at 9,000 feet but I think it will be fine.  If the bike runs okay now with the 42 leave it in.

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Well the bike seems to run fine once it is warmed up. It is just the starting it when cold that it is hard. I have to keep revving the engine with the choke on or it will die. After a 5 minute warm up it is fine. I just wish it would warm up a little easier.

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Well the bike seems to run fine once it is warmed up. It is just the starting it when cold that it is hard. I have to keep revving the engine with the choke on or it will die. After a 5 minute warm up it is fine. I just wish it would warm up a little easier.

 

I'd suggest you go with the 45 pilot jet than.  You should not have to continually stay on the throttle while the engine is coming up to operating temperature.

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If you are running pump fuel this is unfortunately as much a fuel issue than jetting. Running a more consistent and applicable fuel is the best way to maximize effort spent dialing in jetting.

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Well the bike seems to run fine once it is warmed up. It is just the starting it when cold that it is hard. I have to keep revving the engine with the choke on or it will die. After a 5 minute warm up it is fine. I just wish it would warm up a little easier.

 

try this way:  open choke and as soon as it start apply *steady* throttle to keep it at 2500-3000rpm.  what happens after 10-20 seconds of steady throttle? does rpm go down or remain steady? 

yes = you have to put the choke in middle position and apply steady throttle for about 30 seconds untill it can idle alone ,

not = you need a larger pilot jet. 

 

at 5000-9000ft pilot 42 + 2.5turns does not seem  lean to me. in that condition even a completely stock bike can idle alone after 2 minutes, 5 minutes are too much .

Edited by 30x26

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try this way:  open choke and as soon as it start apply *steady* throttle to keep it at 2500-3000rpm.  what happens after 10-20 seconds of steady throttle? does rpm go down or remain steady? 

yes = you have to put the choke in middle position and apply steady throttle for about 30 seconds untill it can idle alone ,

not = you need a larger pilot jet. 

 

at 5000-9000ft pilot 42 + 2.5turns does not seem  lean to me. in that condition even a completely stock bike can idle alone after 2 minutes, 5 minutes are too much .

 

In my experience it should take a lot longer than 10 or 20 seconds to get to half choke.  Even with a 48 pilot it takes my bike several minutes before I can come off of 3/4 to 7/8 choke and down to 1/2 choke.  If you're at half choke after 10 or 20 seconds you are too rich either on the pilot or on the idle mixture screw.

 

I usually give my idle speed knob a turn and start the bike at full choke.  After several seconds I move the choke lever to attain the highest idle speed - Usually 3/4 to 7/8 choke.  Once the idle speed comes up after a few minutes I set the choke at 1/2 and I turn the idle speed knob back down.  After about five minutes of easy riding I turn the choke off.  The process is longer in the winter.

It takes my CRF230 quite some time to get up to operating temperature while watching the head temperature on my Trail Tech.  I always ride it very easy until it warms up and I never shut the engine down unless it has been fully warmed up.

Edited by VortecCPI

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i don't know, perhaps european carbs are different .  my Honda HM crf 230 has a 3 position lever choke: on  , half , off.  i have never tried intermediate positions, i don't need them.  during winter i run 120 / 45 / screw 1.5 turns , snorkel removed, baffle in place (at idle  baffle does not make a big difference)  .

i adjusted the screw to get max rpm at idle.  it never needs more than 30sec of full choke, even in winter at 0°C, and at 15°C it's almost impossible to start at first attemp   without choke : pilot circuit it's not so rich 

 

perhaps the main difference is that i use the throttle while you use the knob.  i do not rev it like mad , however it's possible that my rpms are slightly higher than yours, building heat much faster. for me idling means "engine does not stop" , obviously after 1-2 minutes it idles at much lower rpm than when it's completely hot. i  warm up bikes moving at slow speed ,  as soon as it can barely idle i start moving slowly . if  i would wait untill everything it's perfect it would take longer but there is no reason to wait so long. engine warms up better moving slowly .

Edited by 30x26

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Jetting for 5-9,000 feet elevation has been thoroughly covered so I won't go there.

But at that elevation you absolutely need to add compression (minimum 11-1 and advance the ignition timing (Procom CDI Box) and a Web Cam 40mc/402 CRF 150f torque cam to get any power out of it.

That stock 230 must run like a CRF 50 up there????

You could possibly run a Arias 13-1 compression 67mm piston up there on 91 octane pump gas?

PM (Teamrude)

I'm just saying....

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