woot!! Sent the money for my new bike!

Well Slips - hows it going with that new steed? I noticed that you didnt come back to this post so I fiqure you are doing what I would be doing if I had a NEW KX125 and all that Texas warmth - RIDING TILL THE COWS COME HOME :)
Those Texas Cows are known to stay away a LONG time too!!!
Hope your having fun!
Woodsy

I still have the stock plug in mine from day one never had a problem with it fouling but it could have. Now comes the shocker about the plug, it use's a special racing plug same kind as the newer RM 125's but it's not a #8 it's a #9, the plug # is R-16918B-9
they retail for like $39!! good thing my local kawie dealer realize's he's not going to make any money off them and sells them to me alittle above his cost, he had to special order it threw direct from kawasaki after tax I got it for $29! ouch! good thing it's lasted so long.

MXP1MP said:

I still have the stock plug in mine from day one never had a problem with it fouling but it could have. Now comes the shocker about the plug, it use's a special racing plug same kind as the newer RM 125's but it's not a #8 it's a #9, the plug # is R-16918B-9
they retail for like $39!! good thing my local kawie dealer realize's he's not going to make any money off them and sells them to me alittle above his cost, he had to special order it threw direct from kawasaki after tax I got it for $29! ouch! good thing it's lasted so long.

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The stock plug still? :O

Is that with stock jetting or did you adjust it?

Anyway, The dealer informed me that the original spark plug is supposed to foul because a few reasons: During break in period, you are not supposed to accelerate hard, causing the spark plug to foul, and also the dealer puts 20:1 mix in (for me atleast) so it allows more oil to be spread through the engine which also contributes to the fouling.

Even after this, I have still been having spark plug fouling problems with my 03' kx 125 no matter how hard I ride it, it just seems to foul a plug every ride. I plan to re-jet asap.

Yup has the orginal plug in it, even after I ran it with a 15:1 break in oil for the first 30 mins. After than I've been running it at 32:1 with race gas, I finally changed the jetting after about an hour and half on the bike. So far I've leaned the pilot one size and the main one size and moved the needle to clip position #2. I'm pushing about 15 hrs now on the stock orginal plug.

Tiylu,

I had a lot of plug problems when I first got my bike. I was using Yamaha 2r and went to Mobil M2XT and the problem went away instantly. No more fouled plugs. You might want to try this first.

exactly changing premix is going to have little to no effect. Just change the jetting to 37.5 pilot #2 on the clip position and a 400 main. it's super easy should take maybe 10 mins, unless you like a 125 with sub par throttle responce and wasting money on plugs all the time :)

Well, Im jetting my bike this weekend and I made a thread in the 2-stroke section, but I guess Ill ask here as well..

What should I start with? I was thinking about moving the jet needle clip to the #2 position (3 is stock). Good place to start out?

I find that it's rich on all the circuits by about 1. just do them all the spec's I listed above is what Team Green recommends. Bikes typically come jetted rich stock as like a fail safe against siezing.

Man I can't believe your having so much trouble with fouling your plugs, I haven't fouled a plug yet and I swear I should have by now! *knock on wood* Did you change your jetting yet? I think i'm going to go down to a 400 main from the 410 (420 is stock) i'm still getting alittle bit of oil out of the silencer. I find that it run's a tad cleaner with race gas, but I have only used the R-16918B-9 plug nothing else. When I look at the plug the electrode has that nice tan color you want.

truespode said:

Y2R is a good oil. If your fouling plugs it probably is due more to improper jetting.

Ivan

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I know it dosent make any snese but I fouled 5 plugs in 7 days with the Yamaha oil and have fouled none with the Mobil M2XT oil. I didn't change the jetting just the oil.

I talked with the local Suzuki/Kawasaki dealer and he told me that when he used to race, that if he tried to use a certain type of oil, it would always foul his plugs.

Like I said, I know it dosen't make any sense but my problem is gone.

I see what your saying.

IMHO:
When you change oils or mix ratio's you are, or maybe, ina way changing your jetting (defined as the amount of fuel and oil mix being drawn into the venturi and into the combustion chamber). Oil brands and types all mix differently in gasoline resulting in lean or rich conditions. Also, you can actually increase your oil content in the mix and end up being LEAN because you are replacing gas with oil in the ratio.. AND, yes you very possibly can switch oils and foul less plugs becasue you are running leaner (did the sasme thing as jetting down). The HUGE problem with doing this is that you REALLY have NO idea where you are jetted and therefore, have no idea how rich or lean you actually are...
Here is what you do..
Pick the oil of YOUR choice!! If you wanna BELIEVE that big dollar oil is what you wanna run - run it!! I like something that I can buy ANYWHERE!!! Next, check around and fiqure out what ratio is recommended for your bike using whatever oil you decide to run.
NOW, mix your oil and gas preference up and JET your bike to it!! You will need to do this process (JET) accurately so you have a starting point for ALL future situations (you will know that your bike has a problem of running lean cause you now know what that is :) !
The process of jetting can be fairly simple or it can take HOURS because there can be other things that can cause rich/lean conditions besides the jets in your bike (I spent a day jsut getting my fuel level perfect in my KX - now I KNOW where it runs PERFECT at and its history..).
If you dont know how to properly jet - using plug chops in a proper sequence - I STRONGLEY suggest that you do some research here on DRN and get some input before you tackle it - dont be proud - find the info!!
Also, make sure that you have your air filter cleaned in the manner that you will use to clean it in the future, if you are going to add a spark arrestor or aftermarket pipe do this before you jet or rejet afterwards!!
Your bike is built to run CLEANLY thru the R's with NO spooge and NO plug fouling and you should be able to pull the pipe after 20 hours of running and see a nice clean piston in there with NO scuffing going on!
Woodsy