Oil-fouled plugs

[Rupe]

I was putting a bit to much oil on my filter at one stage, but his only ended up making the bike run more smokey then normal. Is the main jet standard size? if you just puttering around the car park with a over size main jet? maybe?
http://www.snowvalley.20m.com/bikes/jets.htm
Have a look at this might help!

Thanks had a read some good info.

I'm thinking that maybe by winding in the idle screw in to raise the idle speed, it has raised the slide and needle so while idling and at slow speed to much fuel is going through.

I'll try setting a very slow idle and setting the air screw and see what happens next ride.

Thanks for the helpful posts, I'll sort it in the end I'm sure.

[Buddy L]

OK followed a few linky links anf found this its for a 03 ec125,200.250 but im sure they woulden't have changed the bike dramaticly between the years. happy reading.
manual
and parts list.
Just for you.
"Gasoline and oil mixture(premix ratio)(50 parts gasoline to 1 part oil.
Standard Spark Plug
HGK CR8 E o DENSO U24ESR-N Gap 0.7-0.8mm

to big to upload on to KB so heres the link to down load it.
took about 5 mins on broadband to download.
http://www.gasgasmotos.es/esp/frame.htm

[dammad1]

If you want a 2 stroke then you need to ring its neck and rev the thing, if you think you'll only ever be a plodder - sell it and buy a 4 stroke.

On a modern two stroke, if its jetted correctly you can plod along on it as much as you like I have never fouled a plug once on any of my two strokes.

My brothers old race bikes used to foul easily but they were jetted for top end and needed to be kept on the pipe, but this is no good at all for trail riding or cross country's.

[vr4king]

If you want a 2 stroke then you need to ring its neck and rev the thing, if you think you'll only ever be a plodder - sell it and buy a 4 stroke.

Well i got a 1992 cr125 with a BR9EG plug and will happily plod without fouling a plug........I think your wrong if its setup right it should run at any engine speed fine

Having said this though i normaly "blip" the throttle when plodding just to clear it and everytime i pull the plug shes as black well you know lol

[Danger]

Just call Linton. I don't think you have even told us what jetting you are running?

[F5 Dave]

Well I won't poke any more derision at the ill informed flat earth comments about 2 strokes needing their necks wrung, but I guess by association I already have. . .

Main jet largely controls the wide open throttle position so not so relevant. As I said the LTR jet kit helps enormously. Linton probably stocks them, he can get them if you don't want to order on line.

Does seem odd that it is fouling so regularly even so. Have you checked your gearbox level lately? Is it going down? How much does it smoke when warm? (always smoke like a pig when cold).

[smoky]

Well I won't poke any more derision at the ill informed flat earth comments about 2 strokes needing their necks wrung, but I guess by association I already have. . .

Cal me ill informed if want - but it's a known fact,
You’ve got to get a 2 stroke hot to burn off the oil - the best way to do that is rev the thing.
2 strokes are made to go fast, get the revs up and hit the power band - other wise what’s the point of them? If you want torque low down and to plod along then you’re not riding a bike suitable.
The thing about exhaust pulse tuning (fuel snatching) is you only have 2 strokes of the piston to charge and expel the waste in the cylinder. They rely on higher revs to maintain good volumetric efficiency.
Hot plugs, higher revs, and a hot sealed tuned exhaust system. They’re an art form.

[Rupe]

Cal me ill informed if want - but it's a known fact,
You’ve got to get a 2 stroke hot to burn off the oil - the best way to do that is rev the thing.
2 strokes are made to go fast, get the revs up and hit the power band - other wise what’s the point of them? If you want torque low down and to plod along then you’re not riding a bike suitable.
The thing about exhaust pulse tuning (fuel snatching) is you only have 2 strokes of the piston to charge and expel the waste in the cylinder. They rely on higher revs to maintain good volumetric efficiency.
Hot plugs, higher revs, and a hot sealed tuned exhaust system. They’re an art form.

It's fouling plugs on the road from my car, 300-800m depending where I got a parking space. If I ride it back to the car hitting the power band etc I would flick stones over everyones cars, run over a couple of kids, and get kicked out prob.

Anyway I spoke to Linton from Dirt Action Services who has been very, very helpful, and really knows his stuff. He has got me to make a few adjustments for this weekends ride, and fine tune from there. So It should all be sorted over the next couple of rides, as the carb didn't have a standard needle, slide etc.

Anyway thanks for everyones help, I'll put what the changes I made once it's 100% sorted so it might help someone in the future.

[Danger]

Good man! Have fun!

[CaMo]

hey people. Thought I'd post here as is sorta relevant.

Anyway, bought me a new 2008 kx125 and am having a similar problem. Basically the manual and sticker on the bike says to run it at 32:1. I do, and I use yamalube 2-r racing oil.

However, the problem begins when the bike is ridden slowly for about 30-sec (say if you are going down a wet slippery steep hill in the bush and you can't rev the damn thing). The plug fouls up very quick.. Once fouled its a no go so put new plug in.

I use NGK irridiums ( br9eix ). Shop recommendation

the jetting etc should all be standy as when it came out of the shop as am first owner.

Will running it a 40:1 fix this problem? The only concern I have is that the guy in the shop I bought it said you can't thrash it when running this mixture or it will blow up.

I can ride it fine and aint no amatuer rider. Just worried that it is going to cost me a truck load in tyres as I have to be thrashing it everywhere to keep it alive. This aint so good when riding on gravel road etc....

One last thing... I noticed someone mention that yamalube was the reason it was fouling and I am sorta thinking he maybe correct as I did notice this on my older bike a few years ago. As soon as we changed the oil it went fine?

?? Cam

[Rupe]

hey people. Thought I'd post here as is sorta relevant.

Anyway, bought me a new 2008 kx125 and am having a similar problem. Basically the manual and sticker on the bike says to run it at 32:1. I do, and I use yamalube 2-r racing oil.

However, the problem begins when the bike is ridden slowly for about 30-sec (say if you are going down a wet slippery steep hill in the bush and you can't rev the damn thing). The plug fouls up very quick.. Once fouled its a no go so put new plug in.

I use NGK irridiums ( br9eix ). Shop recommendation

the jetting etc should all be standy as when it came out of the shop as am first owner.

Will running it a 40:1 fix this problem? The only concern I have is that the guy in the shop I bought it said you can't thrash it when running this mixture or it will blow up.

I can ride it fine and aint no amatuer rider. Just worried that it is going to cost me a truck load in tyres as I have to be thrashing it everywhere to keep it alive. This aint so good when riding on gravel road etc....

One last thing... I noticed someone mention that yamalube was the reason it was fouling and I am sorta thinking he maybe correct as I did notice this on my older bike a few years ago. As soon as we changed the oil it went fine?

?? Cam

In the manual for my gasgas it states that you should run a hotter plug in the break-in period. This could be the case for your bike, but check first.

Also as pointed out to me going from 32:1 to 40:1 would make the fuel richer and more likley to foul plugs, read through this tread if that doesn't make sense.

I think my problem was the float hight, but I need to test run it againg.

[Danger]

Run the 125 at 40-1 and back the airscrew out a 1/4 turn.

[scott411]

we normally put one smaller pilot jet in the 07-08 KX125's (it is in the spares kit) it helps them stop fouling plugs,

and i agree iwth danger, run it at 40:1

also is yamalube full synthetic, i am not sure ithink it might only be semi synthtic, i wouold reccomend a ful synthetic

Scott, Mr Motorcycles

[Lion]

while were on the subject of jetting, how much will a rejet normally cost?? just done a rebuild and looking at getting the jetting sorted now.