01 Yz125 Wet fouling

Hello I am new to 2-strokes so I need the help.

Okay so heres my problem; I ride for about 30 minutes and everything is fine and the bike runs well. Then when I get off and come back to start it up again it won't start. If I wait a couple of hours or so sometimes I can get it to fire, but after about 100 yards it starts to bog down and stops. After that I can't get it to fire at all. When I put in a knew spark plug the whole cycle repeats itself. Also, oil is dripping out my silencer.

I have cleaned the carb, still no dice. I was using BR9ES plugs. After doing research I bought BR8ES plugs to see if that will fix the problem. If anyone has any ideas to fix my issue that would be wonderful.

Hi there

how do you ride it, on the pipe or lugging it around?

Regards

Arnego2

It either needs to be ridden higher in the rpm range,needs to be rejetted, or if you ride tight technical stuff I would run a br8EG spark plug.

I ride it in the trails, but i try and rip it lower gears as much as possible.

If I were to rejet it, would it stop fouling plugs when I am not riding as hard?

OMG! What a perfect day to log on! I was literally working on my '99 yz125 last night and found that after the new top end, there was oil dripping out the silencer which had bad o-rings so i replaced - However I'm sure it's still dripping.

And after a while of riding, or if it was shut off the bike would bog down until it died only to find the spark plug was dripping wet and black. New spark plug and the bike is back to normal!

The Manual says could be due to overly - rich fuel condition. What kind of jetting changes should we be looking at? Is this something the fuel screw can fix? Or do I need to change jet sizes?

It is oil or fuel what wets your plug? Does the bike smoke grey, white or blue-ish?

regards

Arnego2

You could have antifreeze leaking into your head. Make sure the wetness isn't that. I forget what color the smoke is from that somebody else here would know.

It is oil or fuel what wets your plug?

Well technically wouldn't it be oil AND fuel wetting the plug? Being that they are pre-mixed in the tank? :thumbsup: but plug comes out a wet black

Does the bike smoke grey, white or blue-ish?

regards

Arnego2

idk about MNyz125, but mine is a white-ish gray lol..

what the theory behind a b8 not fouling , does the 8 run hotter than the 9 ?

... but plug comes out a wet black ...

Sure but what kinda smell, fuel or tranny oil. White smoke will be water coling liquids. Grey or a bit darker rich fuel mixture. And bue ish plus white tranny oil.

Regards

Arnego2

Sure but what kinda smell, fuel or tranny oil. White smoke will be water coling liquids. Grey or a bit darker rich fuel mixture. And bue ish plus white tranny oil.

Regards

Arnego2

Gotcha! I'm thinking it's got that fuel smell to it for sure! Tell me.. I really believe it's a jetting issue - Is this something that can be sorted with jet needle? or fuel screw? or will it take new jets?

what the theory behind a b8 not fouling , does the 8 run hotter than the 9 ?

lower the number the hotter it runs on the ngk plugs. most others are the opposite.

Hi there

If you have nothing changed after doing the top a floating level could be the problem. As for jetting that is also the point of where to start. Float high, than if it bogs and dies where does it happen 1/3, 2/3 or at full throttle? When I adjusted my ignition I went from needle position 2 (lean) to number 5 (super rich) at about half to 2/3 of the throttle it went funny.

A lot of spooge problems have to do with riding style. I sold my old RM125 with 180/55/Np3 no spooge and brown plug. The buyer, a young kid has a oily dark plug and spooges all over the bike. I put in a 170/45/and needle in the leanest position (NP1) and it is still black but wont fool anymore on him.

When I ride it the plug is light grey! Keeping that jetting for me would be murder on the engine.

Regards

Arnego2

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now