spark plug problems

[cr125 2006]

Hi I bought a '06 honda cr 125 a few months back and ever since i bought it i has just kept on fouling plugs over and over I've been told to rev it hard which i've done but to no avail.
Could someone please help me as its really annoying me and my wallet the bike is completly standard.

 

[flying flea]

What is your air/fuel mixture, jetting, and fuel/premix ratio?

 

[Red Pinger]

The best fix is a James Dean jetting kit if you have the money. Or you could drop down a couple sizes on the pilot jet, that won't cost too much and will help a lot although it wont be perfect. For a temporary fix if you don't run it too hard you could run a hotter plug. Br8EG A lot of guys just run a hotter plug and don't bother with the jetting even though it's not the right way to address the problem.

 

[cr125 2006]

my fuel mix is 40:1 also i have tried using br8eg and it makes no difference

 

[helio lucas]

try to turn your air screw 1\2 - 1 back, drop the needle in the clip 1 notch and see if helps...

 

[cr125 2006]

sounds complicated i dont want to mess it up i think i'll leave it to my mechanic

 

[mox69]

I'm guessing you were only revving to 10, rev it to 11 and it will be fine. :bang: :bang:

 

[Timmay#678]

I'm guessing you were only revving to 10, rev it to 11 and it will be fine. :bang: :bang:

The one time its ok to bang her off the limiter! :cool: .

Anyhow, I know this bike, the previous owner had a full hgs pipe on which he removed, but I don't think the jetting was changed back fully. The main jet was reduced from a 440 to a 420 when the op got the bike, but I'm thinking that that'll only effect WOT? And a normal beginner like you wont have it reved that hard anyway, so its the things that effect less than 3/4 throttle that we should look at?

If we do drop the needle and open the airscrew a bit, is there any chance of making it run too lean, or would only too small a main jet leave you with any chance of seizure.

 

[rmc_olderthandirt]

my fuel mix is 40:1 also i have tried using br8eg and it makes no difference

What was the other plug that you tried?

If the difference in the plug wasn't in the number (using an "8" instead of a "9") then I wouldn't expect it to make any difference. In other words, if the other plug that you were using was a B9ES then going to a BR8EG should help.

On the other hand, if the other plug was a BR8ES and you tried a BR8EG then the heat range of the plug didn't change, and thus I would not expect any improvement in fouling. If this was the case, try a BR7EG or BR7ES.

Note that the difference between the EG and ES in in the electrodes. The EG would be a longer lasting plug, but that applies ONLY if the plug gets to wear out instead of foul out.

I would also recomend that if going to a hotter plug (lower number) helps the fouling you should keep a close eye on the condition of the plug. As your skill improves and you start pushing the bike harder it could lead to overheating the plug.


Rod

 

[longtime coming]

Mine works

I have a 2006 CR125 also. It was goofy rich on the bottom stock. Bought JD kit. Installed 420 main, 35 pilot and red needle at 4 to start, then dropped to 3 as the weather warmed up. Still occasionally fouled a plug. So went to BR8EG and problem cured. It still is rich on the bottom and if warmed up too long, it will threaten to foul but cleans up quick. The airscrew adjustment should fix low throttle opening issues. It does not run perfectly for sure, but is pretty good and when the weather is right, this bike hauls a** in a very short upper mid sort of way. Nice 125.

 

[TWRT]

Changing the jetting on a bike is not hard or complicated. Get a manual or check on-line to find what is meant by 'pilot' jet, 'main' jet, 'needle position' and air screw. Changing the pilot jet down 1, is a good start. Lowering the needle may help also. Changing jetting can be a trial and error routine. You will get to know your bike when you work on it yourself. Do not be afraid of working on your bike, it will pay off with $ saving and a sense of satisfaction. A good crisp running 2-stroke is a wonderful thing.