Can you foul a four-stroke plug?

[crustydemon1970]

Can someone give me the skinney on if you can foul a spark plug on a four stroke yz 426?

After I had my valves adjusted on my bike, the bike has difficulty starting. I replaced my plug after the valves were adjusted because the bike was adling rough and smoking. After replacing the plug I was still having starting the bike and once it was started it soon died and wouldn't start again. I even tried to bump start it with no luck.

Any suggestions?

Chris

 

[Papakeith]

you can foul a 4 stroke plug. My XR200 does it fairly often. Of course the rings are toast and the plug gets oil fouled

 

[crustydemon1970]

so most likely my rings are worn and I need to do a compression test / top end job?

 

[crustydemon1970]

and how do you tell if the plug is fouled?

 

[wildbill2]

Yes you can foul a plug. When starting and the bike gets flooded. If the plug shows signs of blow by replace as well. Check your plug wire and cap that could be part of your problem.

 

[confusedtech]

If the problem started after having the valves adjusted maybe they are too tight.If they are too tight you loose compression if the valve is open a little.

 

[crustydemon1970]

I pulled the plug and noticed there was coolant on the plug. (might have something to do with no spart/start). Why would coolant be on the plug? Could I have put to much coolant in the bike?

 

[Papakeith]

head gasket leak is one posibility

 

[crustydemon1970]

coolant in spark plug valley / bad head gasket?

I pulled the plug again and noticed coolant all over the plug.
I then drained the coolant and removed the plug. I kicked the bike over a few times and noticed coolant shooting out from the spark plug valley. After a while coolant stoped shooting out. Should I now try and replace the coolant to see if the valley fills again? would this verify a bad head gasket?

Chris

 

[IndyMX]

I pulled the plug again and noticed coolant all over the plug.
I then drained the coolant and removed the plug. I kicked the bike over a few times and noticed coolant shooting out from the spark plug valley. After a while coolant stoped shooting out. Should I now try and replace the coolant to see if the valley fills again? would this verify a bad head gasket?

Chris

No.

But a compression test might.