Just put a new wiseco piston, vforce 3 reeds, and a jd jetkit in my 04 rm 125 now when i try to rev it up quickly to get in the powerband it bogs bad but if you rev it up real slow it does fine and, after it is in the powerband it rips, but when you get out of the powerband then it will bog when u try to get back in to the meat of the power. even when you have the clutch in it still bogs bad when you twist the throttle quick. and if you just keep the throttle wide open when it is bogging it will bog for like 20 seconds then it will finally rev up and accelerate. it idles great and starts first kick and raises hell when its in the powerband. i did exacaly what the directions of the jet kit said and adjusted the idle and air screw to what i think of good but it still bogs. btw the bike did not bog before i put these parts in it. thanks

Try going in on the air screw, you may need to go up on the pilot jet also the needle may need raising a clip, Do a plug chop as you may also be a little lean up top

Exactly what is a plug chop do you actually chop the plug because the OEM plug for a rm 125 is 40 bucks I dont want to chop $40 too many times lol. and it runs not so great with regular plugs

Also its got a pro circuit works pipe and Shorty silencer

My jetting is main jet: 420 pilot jet: 35 standard needle 3rd clip position. That is what my JD jet kit reccomended.

Plug chop  ride the thing flat out under load, whip in the clutch kill the motor with the kill switch,remove plug and see what colour it is !!!! looking for a chocolate colour not a white or black plug as to see what your main jet settings are like

Recommended jetting is a starting point ! the weather / elevation pipe ect is a big factor on jetting correctly

Edited by johnnyboy, 23 June 2012 - 07:36 AM.

kxkawirider, did you ever determine the problem with your bogging issue.  I have the same issue with an '02 YZ125 that I can't fix with pilot jets or needle position.  There is some history I could share that may help others answer, but it would stir up a whole bunch of other questions I am sure.  Might be helpful for me and my problems if I knew what happened to yours.

Thanks.

johnnyboy, on 23 June 2012 - 07:33 AM, said:

This is incorrect. You DO NOT read the tip of the plug for color. This tells you nothing.
What you are looking for is A RING AT THE BOTTOM OF THE CERAMIC INSULATOR and that is where you read the color. You want light chocolate milk color.

Krannie, on 07 July 2012 - 11:56 AM, said:

Once again you turn something as simple as getting a good guide to how a engine is running into a complex nightmare for all the less experienced
You are correct but if NGK gives guides how to read a plug I as well as others will have to go with them and not yourself
Must remember to take a lathe or at least a hacksaw with me on evey ride as to determine my jetting
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