2005 Honda CR125-jetting

Discussion in '2-Stroke Discussion' started by GatorNutz, Mar 7, 2005.

  1. GatorNutz

    GatorNutz Rookie DRN Member

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    I have a brand new 05 CR125. Stock it says to run a BR9EG at 1 3/4 turns out on the air screw. I've tried 1 3/4 turns to 2 1/2 turns. Still fouling out even on the pipe the whole time. I was told to run a BR8EG(or BR8ES, i don't know which one is better) and 2 turns out on the air screw. I live in Southeast Texas, near Houston, lots of humidity. This weekend i will try running the BR8EG, if anyone has had the same problem and knows of a fix let me know. Thanks, Scott


  2. Sayntmatt

    Sayntmatt Rookie DRN Member

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    I have a 05 CR125 also and mine fouled a few plugs whilst running in but it hasnt since (touch wood) although it does make a lot of smoke and spooge! I live in UK so our climates are probably very different but I dropped the needle one notch, went one smaller on the main and one smaller on the pilot. This has helped a bit but as I say its still a bit smokey! My bike is on a BR9EG plug at the mo! I must say tho when you open mine up on the track it really rips!!! Great motor if you ask me!

    I must point out also that I do race but Im not that fast so I dont know if that jetting would be any use to a faster rider???

    Oh yeah and I run 97 oct fuel (reccomended over here) and 125cc of oil to 5 litres of fuel! Dunno if that will help??
  3. GatorNutz

    GatorNutz Rookie DRN Member

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    I'm using the Honda HP2 oil @ 32:1 ratio. I really would like to stay with the stock needle and pilot and just get my ratio, air-screw and spark-plugs on the money. Thanks for any help, Scott
  4. MXP1MP

    MXP1MP Rookie DRN Member

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    so what if you have to change the needle they are not that exspensive about 3 spark plugs later and you've basically paid for a new needle. Playing around with your mix ratio isn't going to dail in your jetting. If I had an '05 CR it prob end up like the last few 125's I have owned the jetting get's leaned out right away. Within the first week of owning the bike i'm sure I would have all ready gone leaner on the pilot by one, one leaner clip on the needle and one leaner on the main.

    On my KX 125 I went one leaner on the pilot one leaner on the clip pos and 2 sizes leaner on the main air screw @ 1.5 turns out. It doesn't foul out at all anymore and I've gone threw just 2 plugs only a year and half later but then again @ $30 a plug I was determined to dail it in and fast! BR9EG's are what like maybe $5 a plug.

    Jetting spec's are temporary you can always change it if you don't like what you may have changed.
    I always try to jet my 125's as lean as possible before the negative effects of going to lean start to happen.

    What is the stock spec's for '05? on my '01 CR 125 stock was #45 pilot needle # 2068 in the 3rd clip with a 380 main and some funky 2 & 1/4 turns on the air screw. Final specs were #40 pilot #2170 needle #2 pos kept the main @ #380 air screw @ 1.5 turns out. I wasn't finally able to dail in the bike till I changed the needle. Honda has it that the 20 series needles was like stock range and the 21 series was a half step leaner over stock. So I how it compares is the #2170 is 2 and half step's leaner over the #2068 and only half a step over #2070 needle. *** sometimes they refer to it as half clip leaner position not steps ***

    So what I would suggest is learn the honda needle numbering system and start diagnosing your bikes jetting.

    oh yea btw what do you guys think of that newer motor? I'm trying to get my friend to sell his 250F and get a CR 125 to compliment his CR 500AF.
  5. Sayntmatt

    Sayntmatt Rookie DRN Member

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    I have never ridden a 250F but I think the new motor is very good! Its easily better than my 04 YZ125 was and a lot of the mags are saying its very close to the new YZ in performance!

    Overall I am very pleased with it and I would recomend one to anyone after a new 2stroke!
  6. marcusgunby

    marcusgunby Lifetime Sponsor

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    You need to drop the main by 2 sizes and the pilot by 2 sizes, then lean the needle on clip-that will get you close.
  7. trickin30

    trickin30 Rookie DRN Member

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    Hi...

    I also have an 05' CR 125. I eneded up dropping the pilot to a 45 from the 55. This kept it from loading up and fouling plugs all the time. Keep the same plug (BR9EG or EV or EIX) or you can risk head damage. The FMF Fatty and Shorty silencer work great. I just installed the Power Now and Power Now plus with the V-Force reeds and am having to rejet all over again. If your stock just drop the pilot to a 45 and you will be in great shape.
  8. jrideswitch

    jrideswitch Rookie DRN Member

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    Ya me too Just bought a new cr125 2005, And can't even break it in...it's fouling steady. can't even come close to idle for more than two seconds...loads right up. I've gone from stock mains(430) to 410 and still fouling plugs,not that often but I could break it in without trying to kill it. I'm going to a 50 pilot from the stock 55 and try it again. But for some reason ,i think I'll end up with a 45 pilot. If I hold it open,it's reving out but sounds rich still. might have to try a 400 main. These things come very rich jetting......Right now I'm riding in 0-5 deg temp and you would think I'd have a lean problem,but no way...still very rich....
  9. MXP1MP

    MXP1MP Rookie DRN Member

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    Current jetting in my friend's 06 is 50 pilot 2167 needle in the 2nd clip that one size leaner than stock and went up one richer on the main to a 440. It's mostly stock cept the FMF fatty and Vforce V3. It was running like crap even tried the 45 pilot right away and it seemed to have helped. Second ride out some how lost the screw for the rear air boot clamp. Was okay for awhile it was always sorta wierd acting. Found out the clamp was broken a few weeks ago and fixed it yea it's running much better now with those jetting spec's it hauls now.

    I noticed on the OEM piston there are no cooling holes on the exhaust bridge side? So before installing it drilled 2 small holes like you normally find'em for cooling effect will it do anything maybe. I don't know how much longer it's going to stay a CR 125 I think it's going to be 139'd soon. I know it used to compare to my '06 yz 125 but not as a 144 it doesn't no more :)
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