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Riding too rich, now piston is brownish, fauled

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Hey guys,

I run a Honda CR250 2001 - great machine!

I just found out that my air screw was ½ turn too little outwards - making the mixture to rich.

I noticed it because the bike started to leak oil out the exhaust connection points.

I also checked the plug and the piston. Plug is black/oily. Piston is darkened too. (See photo)

Now I readjusted it the air screw.

Is there any procedure to undergo, like cleaning the piston/cylinder/plug before I run it?

 

Thanks guys.

foto (1).JPG

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Air screw only affects low (idle) speed operation.  You probably have other problems.

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Well that actually explains it, because I have been riding a long, very low RPM trip, like idling at the time the air screw was too closed. That explains the fouling of the plug and piston.

Do you recommend using a burner on the plug, or must it be changed ? Should I clean/ polish the piston?

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Hey guys,

I run a Honda CR250 2001 - great machine!

I just found out that my air screw was ½ turn too little outwards - making the mixture to rich.

I noticed it because the bike started to leak oil out the exhaust connection points.

I also checked the plug and the piston. Plug is black/oily. Piston is darkened too. (See photo)

Now I readjusted it the air screw.

Is there any procedure to undergo, like cleaning the piston/cylinder/plug before I run it?

 

Thanks guys.

your rings (and piston) are toast.massive blowby.

 

your mixture screw being a hair out only affects performance and not the longevity of engine parts(that small setting change won,t affect wear).

 

your engine has too many hours on it.

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Thanks guys,

You're probably right, i have a blow by, and the piston has many hours I think from the previous owner.

But I just proved that it also was a jetting problem - after I did the air screw the piston "cleaned up" and looks almost normal. See picture:)

The plug is now dry and black.. But it should be brownish right?

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Half a turn out on your air screw makes your mixture leaner, not richer. And that half turn shouldn't barely make a difference in overall richness/leaness of the motor. Your jetting is off because your motor is wore out. It needs a piston and rings!

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