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00 cr250 jetting in wa state. Help Please!!

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so im new to carb tuning and my new bike i bought (00 cr250) came with a 172 main and 48 pilot. i know the stock ratio is 180 main and 48 pilot. I have a fmf gnarly to fmf shorty with carbon reeds an newish piston. The previous owner ran 50:1 and it seems way high i want to be at or around 40:1 just for peice of mind. Gonna do tear down later this year to see her in sides which i will keep posted also working on 10 acre track too so alot goin on.:bonk:

So i went to bbrp a local shop an bought some main jets got a 178 and 180. Using stock needle. set it all back to stock but wonder what main jet i should run to compensate for add on's.... Should the stock needle be ok or should i get the optional needle. dnt really wanna spend 80 bucks on jd kit when it runs good now just want smoother power. Also seems to run like its gonna blow when i pull the choke with old jetting dnt get what that is all about, cant use the choke cause im worried its gonna blow.:busted:

Question: Any one with the same setup with input? Should i run stock jetting or should i go lean or richer? Im practically at sea level and its around 45ish degrees. Prolly not the best time to start jetting bike cause its freezing but i got time and could use the knowlege. also if someone has dirt moving machinery and wanna help on a private track pm me would love the help!!:busted::lol:

also have needle with clip on third groove from the top, was on 2nd from top.

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2000CR250Jetting.jpg

this correction chart is a good one. it assumes that your perfect jetting is 48p, needle on 2, and 172m. this is at 0' elevation and 70*F. i jetted my bike before finding this chart and when i found it, i thought it was funny that i landed on the same jetting. i agree on the jetting on all except for the pilot, but thats a tiny issue.

i use stock reeds however. if you are at 40*F then the stock jetting with 1 main reduction should suffice.

i actually use an optional needle from a 99 cr, but the correction chart above assumes the stock a715 needle, and i also had good luck with the stock needle.

this chart was made by a fellow TT member, unfortunately i do not remember his name.

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not that i have seen. the original poster did all the work and just made it into an easy to use chart for 2nd gen honda/pwk users. for your bike, youd have to do a little leg work. there are correction factor graphs that you can use to help get a good start on jetting on days where temps have changed a lot since you had your bike "perfect" or for when you go to a new location that might be a couple thousand feet above or below from where you usually ride.

Correction factors are sometimes used to find the correct carburetor settings for changing temperatures and altitudes. The chart in fig 8, shows a typical correction factor chart. To use this chart, jet the carburetor and write down the pilot and main jet sizes. Determine the correct air temperature and follow the chart over to the right until the correct elevation is found. Move straight down from this point until the correct correction factor is found. Using fig 8 as an example, the air temperature is 95deg Fahrenheit and the altitude is 3200 ft. The correction factor will be 0.92. To find out the correction main and pilot jets, multiple the correction factor and each jet size. A main jet size of 350 would be multiplied by 0.92 and the new main jet size would be a 322. A pilot jet size of 40 would be multiplied by 0.92 and the pilot jet size would be 36.8.

correction.gif

i have not been able to find one that had anymore elevation info. all of them seem to just go by the 1000 meters which i dont really like, because in my experience, sea level to 3k feet will require a decent jump in jetting (for my bike, its almost 3 main sizes). im not sure how to actually graph the inbetween sections unless you just draw a line dead center (which wouldnt make sense as the others arent spaced exactly evenly)?

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but any local knowledge im in the pnw? im try a 178 main and 48 pilot with needle on third clip. Its pretty dawm cold here too:thumbsdn:

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ok so i tried the new jetting which was 178 main and 48 pilot with needle on third clip. seem to have more grunt on bottom but at the top it seem to blurbel or just didnt have the snappiness as it did. Im super new to this so idk what ima start with prolly go 175 main an see what that does.

It came with 172 main 48 pilot and needle on the second clip. so maby try moving the needle up first with the 178 main. Also changed my premix ration from 50:1 to 40:1

When i first started it it was definatly rich in fuel till it got warmed up then it ran fine. Adjusted the air screw a lil bit to make it idle smooth .Took it out to my track and rode prolly 15 min and definatly a big change in jetting. It lugged when i would try to pop the clutch an wheelie, i.e. never did that before. The temp outside here is about 45 to 50 f. Any suggestions?

What ima do next-

adjust the needle back to the second position 1

Go to a 175 Main 2

possibly see what a 180 main does 3

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given temps you listed I assume you're at sea level as rest of WA is colder now. Try 175 main. Can't power wheelie now? Means you're too lean on pilot since chart indicates need for 50 PJ. Also, you leaned available fuel coz you added more oil which pronounces the already lean pilot.

You could try 50:1 and 3/4 turn on air screw. That's prolly make your 48 closer to a 50.

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im gonna go grab a 50 pilot today and see how that works and grab a 175 main. try them both together today an report how it works back to u. Thanks for the advice shrubitup ill try that advice:ride:. i dnt wanna run 50:1 so ill grab those pj and mj today an let u guys know how it works:ride: and yes i am at seal level im in the very nw corner of washington, bellingham.

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worked good but a lil funny up top. I talked to my buddy that is really into bike for years he yelled at me cause i didnt use a jd jetting kit. could jd kit help more than just throwing in some random jet sizes. Im not a profesional nor anything close to konwing how to perfectly jet a carb.

Should i just get a jd kit and follow there instructions or try to do it manually for the knowledge?

175 main 50 pilot and needle on 3 clip worked good just a lil sputtery on top

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Try 172 main and possibly second clip. sputter=rich.

JD is good - no doubt but it sounds like you're nearly there - at least for this elevation and temp. I like JD coz it tends to be less tempermental with elevation than a OEM needle.

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worked good but a lil funny up top. I talked to my buddy that is really into bike for years he yelled at me cause i didnt use a jd jetting kit. could jd kit help more than just throwing in some random jet sizes. Im not a profesional nor anything close to konwing how to perfectly jet a carb.

Should i just get a jd kit and follow there instructions or try to do it manually for the knowledge?

175 main 50 pilot and needle on 3 clip worked good just a lil sputtery on top

IMO, your pilot is rich and your needle clip is rich. dont just throw in random jets. the pilot and main have a very effective and objective way of being set.

use the air screw setting to find your proper pilot, and a true plug chop to set the main. use the needle to adjust the transition from the pilot to the main.

the JD comes with 2 needles. the rest is all normal jets. honestly, the air striker comes with a needle that is very much usable in the 00 cr250. another needle that works good is the 99 cr250 1370dka needle (optional needle). one nice thing about the 99 needle is the fact that its a dual taper needle and all the measurements are easily found if you need to tune. the JD needles only give you 2 options, and the 00 needle is a triple taper and there arent replacements other than the optional honda needles which only differ in straight diameter.

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so i finally got it i put back to old jets and clip positoin then i bumped up the mj by 1 so it was 175 instead of 172 and bumped the sj to 50 instead of 48 and left the clip on the second position and bing! it ran great i went through the steps an got there without jd kit but still gonna buy one once new year comes around an when im riding alot. Did it for the experience and gained alot. Runs much smoother now augh i feel proud lol:bonk:

This will be my winter setup for 40:1 mix (usta run 50:1 Yikes)

sj-50

clip-2nd

mj-175

idle thing 2 full turns from seated

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I know this is an older thread, but thought I would input ...

My JD kit for a '99-'00 said to put in a 182 main, a 45 pilot, and their "blue" needle on 3rd clip (the blue needle is richer than the red, so colder climates and lower elevations).

Seems that since you are using a 50 pilot it makes it necessary for you to use 2nd clip with your needle (to lean out the pilot's transition onto the main)? IDK, but perhaps its worth a try.

I'll install my kit and tell you what I experienced going from the stock 180/48/3rd on stock '00 needle.

Edited by 2strokes4me

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