2 Stroke CR 125 01 Fouling spark plugs

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madguru100

ossagp:
Did you try turning the choke knob down. the only jet that seems like it may act too rich to me is the 60 slow jet, and we ran 40-55's depending on the weather/temp on the mid 90's cr125s. you need to check to make sure that the fuel is actually shutting off though.
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It usually fouls after i go up the trails and it just loses power i ride it all throughout the throttle range . I'm waiting for the baffle part of the carb cause i broke it then i can try the choke knob could this fix the fouling? I might buy a 55 slow jet just to try it out also but does the slow jet make the plug foul? Or is the main involved too? Cause on the lower throttle it doesn't run really crisp unlikes the mid and top range
 
M

madguru100

ossagp:
I want to say that honda was actually calling that a 35 for whatever reason, but that is just a 20 year old memory i am dragging on. anyway, not the greatest carb to have on one and it is old since honda hasnt sent one since about 97.
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Yea i might invest in a new carb soon but for now i have to make do financial crisis are a pain xD
 
O

ossagp

yep, and i think we can work you through that. the bleeding choke is dealt with by ruling out all chance of air passage over that circuit and thus drawing fuel through it. if that doesnt work we need to check for leaks at the float and sometimes those only come with vibration. i would feel a little better if that had a pilot jet in the 40's though for clean running and for coastind down hills with the brakes on.

set the low speed air out about 2-2.5 if the knob doesnt fix it on its own. dont take it past 2.5 and ride it because the screw comes out. that is really the only reason not to use it to lean it out more if it actually does an adequate job of setting the mixture
 
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M

madguru100

ossagp:
yep, and i think we can work you through that. the bleeding choke is dealt with by ruling out all chance of air passage over that circuit and thus drawing fuel through it. if that doesnt work we need to check for leaks at the float and sometimes those only come with vibration. i would feel a little better if that had a pilot jet in the 40's though for clean running and for coastind down hills with the brakes on.
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Yea definetly any idea in what range of pilot jets i should buy? Thank you very much for all the help i greatly appreciate it . So 1st i'll try the screwing in all the choke knob it was pretty out from the start when i bought it maybe that's why . 2nd : We check to see if theres leaks alright . Thanks mate :) i'll try everyone out when i get the baffle btw have you got any idea where i can buy the baffle part of the pj 34 in europe cause i can't seem to find any thanks
 
M

madguru100

madguru100:
Yea definetly any idea in what range of pilot jets i should buy? Thank you very much for all the help i greatly appreciate it . So 1st i'll try the screwing in all the choke knob it was pretty out from the start when i bought it maybe that's why . 2nd : We check to see if theres leaks alright . Thanks mate :) i'll try everyone out when i get the baffle btw have you got any idea where i can buy the baffle part of the pj 34 in europe cause i can't seem to find any thanks
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ossagp:
yep, and i think we can work you through that. the bleeding choke is dealt with by ruling out all chance of air passage over that circuit and thus drawing fuel through it. if that doesnt work we need to check for leaks at the float and sometimes those only come with vibration. i would feel a little better if that had a pilot jet in the 40's though for clean running and for coastind down hills with the brakes on.

set the low speed air out about 2-2.5 if the knob doesnt fix it on its own. dont take it past 2.5 and ride it because the screw comes out. that is really the only reason not to use it to lean it out more if it actually does an adequate job of setting the mixture
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So if the the the choke knob doesn't fix the fouling i'll need to take to take the air fuel mixture screw 2-2.5 turns out? If that doesn't fix it i go down a pilot jet right?
 
O

ossagp

pilot jet and check for leaking at the needle and seat or as some of the older keihins of any model develope leaks behind the brass sleeve that the needle rides in
 
M

madguru100

ossagp:
pilot jet and check for leaking at the needle and seat or as some of the older keihins of any model develope leaks behind the brass sleeve that the needle rides in
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Alright mate so the cause of the fouling must be from the pilot jet , the choke knob or leaks from the needle and seat? Nothing from the main jet and needle ? Cause it seems to run fine in mid range and top range but low range is pretty naf and doesn't run cleanly on the low end
 
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ossagp

i think you are correct. and i would bet that if you took it out on a straight fast stretch and screamed it out, got it good and warm and cleaned out and then backed off of it and let it roll to a stop in gear it would be fouled, even after it ran like a scared spirit on top.
 
M

madguru100

ossagp:
i think you are correct. and i would bet that if you took it out on a straight fast stretch and screamed it out, got it good and warm and cleaned out and then backed off of it and let it roll to a stop in gear it would be fouled, even after it ran like a scared spirit on top.
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Yea that is exactly what happens we'll try that pilot jet fingers crossed hope its an easy fix
 
M

madguru100

ossagp:
what did you say the air screw was set at now?
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No idea i'm a noob in jetting i'm setting a stepping stone and trying out to learn how to jet xD . Do i count the turns and tighten it with the screw driver until it stops? Is that how to find out right?
 
O

ossagp

yeah, turn it in slow and easy and count the amount of turns it takes. dont turn it in tight, just bottomed. i use an easy to finger twist with a light grip. stock they set around 1.5 to 1.75. if yours is less than that it is richer than stock. that screw on that carb like most two stroke carbs controls the air flow over the slowspeed or pilot jet and not the fuel (directly that is).
 
M

madguru100

ossagp:
yeah, turn it in slow and easy and count the amount of turns it takes. dont turn it in tight, just bottomed. i use an easy to finger twist with a light grip. stock they set around 1.5 to 1.75. if yours is less than that it is richer than stock. that screw on that carb like most two stroke carbs controls the air flow over the slowspeed or pilot jet and not the fuel (directly that is).
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Seems to be like around 3.5 turns out but i think its 4 . Pilot jet is 60 i think i might need to go down to a 55 right? Cut it down from long story to short it is more than 1.75 xD
 
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