Questions about my 98 YZ125

[YZER-409]

My first question is what do you guys mix your fuel. Also what type of mix do you use. I use 42:1 and I foul plugs within 5 minutes. Do you have any suggestions on what to check. I have a clean air filter, I use a BR9EG spark plug. Also when I start it cold it starts first kick without choke. I checked the choke its sealed perfectly. My main jet size is 052. I put a smaller jet in and it still fouls. Help!!!!!!!!!!!!!!

[SirFallsALot243]

Try your pilot. Run it at 32:1 or 36:1

[YZER-409]

If I ran it a 32:1 or 36:1 it would foul it much faster.

[Satch0922]

clean your carb and blow out all the jets with compressed air. I run my 250 at 32:1 and have not fouled out yet! It still has the stock plug (o two rides on it).

[Shifting]

Your thinking about it wrong. 32:1 is 32 parts gas to 1 part oil. 42:1 is 42 parts gas to 1 part oil. Buy mixing in more oil you will lean out the jetting by using the fuel mixture. There is less gas in the fuel mixture so you have leaned the fuel mixture. This will help but is not the whole problem. It sound like the bike is running way rich.

[ossagp]

I bet your carburetor has not had the float set in ages. This is a maintenance item. FYI Chad Reed's got set before the last moto and will get it again before the next one. So every 7 years wont hurt yours either. Seriously, set it monthly. Faded posted a real good instructional on it here on All Things Moto. People still want to bandaid a float problem with jetting and "is my ratio wrong" fixes.

Before you buy anything, read his post, set your float and then decide if you still have a problem you need to buy something for.

[Satch0922]

Originally Posted by ossagp

I bet your carburetor has not had the float set in ages. This is a maintenance item. FYI Chad Reed's got set before the last moto and will get it again before the next one. So every 7 years wont hurt yours either. Seriously, set it monthly. Faded posted a real good instructional on it here on All Things Moto. People still want to bandaid a float problem with jetting and "is my ratio wrong" fixes.

Before you buy anything, read his post, set your float and then decide if you still have a problem you need to buy something for.

There is your answer!

[Aus_Rider_22]

Check out the following thread.

It has a vast amount of info on jetting on the later YZ125's.
It also contains page on how to set your float.

Jetting Recommendations?

[YZER-409]

I already new about the gas and oil mixing, and the carb was just redone, and cleaned but I will redo it just to see what happens.

[Aus_Rider_22]

Doesn't take much or long for float to come out of spec.

Mine often spits out fuel if it's left on.
Follow Faded's guide and you should be sweet!

[YZER-409]

Does anyone know the stock settings on the carb for a 98 yz 125