jetting advise

[cr125xr600]

hi, im new to the two stroke world. i recently bought a 02 cr125 , and if you take off without letting it warm up for a few minutes it will fuel foul the plug, it also has no low end power. from what im reading it is a jetting problem. my question is my bike has a wiseco piston(lighter) and v force reeds in it with a stock primary pipe and a fmf silencer. i have no idea what jets are in it . do i need to go back completely stock jetting or does anyone have a baseline where i should start.using hp2 oil and 93 octane fuel . stock plug

 

[2 strokes for life]

Go with a 175 main jet, clip on needle 2nd from the bottom air screw 1 3/4 out and that's about it. If you find it still not getting enough fule put in a one step up pilot.

 

[mongial]

Do not run a 175 main. The stock main jet for this bike is a #400 as listed at Service honda under parts. I don't think that a Cr 125 is going to have very much bottom end period.

 

[burgunder]

Always let the bike warm up before you ride it. If you don't, you risk a cold siezure. Wiseco pistons are even more prone to cold siezure because they are forged. I warm up my bike for over 5 minutes before riding it. Proper jetting can not be done until the bike is warm anyway. Read the jetting threads to learn how to properly jet your bike. No one can tell you what the perfect jetting is, because jetting requirements continuously change do to altitude, temp.,humidity, fuel, oil, riding style, terain, and bikes condition. Good luck.

 

[2 strokes for life]

Well put burgunder.

 

[KX250Dad]

burgunder... good job
Seems many riders in their hast to get the big air don't allow time for warm up, and some even forget to turn the choke off... the later will make a bike bog, just ask my son cost him 1/3 lap before he figured this out and he's an experienced rider. If your a heavy fellow (I'm a slim 225#) the bike will feel like it boggs until your hooked-up at 8000r's+ So if this is your first bike it may be a how to ride opposed to expectations thing. Remember, in a 2T the power is in the r's

 

[2 strokes for life]

My old junker dosent matter how long or how short it idles for. The power dose not clean up till i hit it full throtle in third.

 

[cr125xr600]

thanks for the advise .

 

[just_a_rider]

My old junker dosent matter how long or how short it idles for. The power dose not clean up till i hit it full throtle in third.

That tells a story, it sounds like your main jet maybe ok but you could drop to one smaller to crisp it up. The main controls the flow from half to full throttle, the needle jet is your mid range controlling from a 1/4 to 3/4 throttle, to lean it you go up with the clip making the needle go down filling in the hole a little more, the pilot jet controls from idle to 1/4 throttle and if it is to rich you'll foul plugs and smoke like a steam engine and get spoooooge. Lots of people think it's the way your mixin fuel and oil ratios, more oil the richer is not the case. The fact is that a bike thats running rich is just getting to much fuel and can't burn it all resulting in fouled plugs, spooge and just running bad all to gether. I bike running a 32:1 mix ratio thats jetted right will be strong all the way through the stages with less smoke and spooge + getting the vital lube it needs.

 

[2 strokes for life]

So this means i should run the needle clip one up or down. I also run amsoil 50:1 just because my friend is a supplier.

 

[just_a_rider]

Drop your needle one notch at a time till you feel your mids come to life and mix 32:1, It might sound strange but it will help lean the bike. You can also play with the air screw, running it out past the recomended setting which is usualy 1 and 1/2 rounds out, more air leans so running it out will lean it. If you drop the needle as far as it will go and the mids still feel slugesh you may have to get a diferent taperd needle to coinside with the opening better.

 

[2 strokes for life]

So if i drop it then that means the clip goes down. But it only dose this when i take off for the first couple mins of riding and then clears up for the hole day.

 

[2strokerfun]

Nope. To drop the needle, the clip will come up. That way, the needle does not rise as much when giving it throttle, making a slightly smaller orifice and leaning the mixture. Drop needle=clip up. Raising needle=clip down.

 

[cawkazn]

from most of the reading i have been doing, i was going to get a cr. in 02 they changed they reeds or something that wasnt the best idea. the bikes were known for no low end power. in 05 they changed it back to they old way or whatever. i want to get a 05 cr 125 or newer. heres a link about the 05 125 shoout out. the yz took 1st cr 2nd


http://www.dirtrider.com/tests/motocross/141_0502_2005_honda_cr125r_yamaha_yz125/