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Intake valve goop

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So I have my air box and carb off of my 08 crf250 right now and I decided to look down the throat of the intake with a flash light and omg there's a thick black cake/ crust on the tops of the intake valves :ride: Is that dirt from the infamous bad boot seal? Or is this a normal build up of engine gunk? I'm going to take the head off and investigate because it looks as if it has a sandy texture :thumbsup: Just wondered if anyone else has noticed this. And yes I keep my filter spotless, and there has been no valve movement.

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may be air filter oil/dirt that got sucked through. maybe ur filters are not drying enough, thinning out the air filter oil and its making it easyier to get sucked through.

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I doubt it, i use bel ray. The stuff is so tacky. plus there wasn't any on the inside of the boot

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weekend trails rider, low rev low speed technical stuff

Carbon. Gas it now and then.

My Dad used to take Grandma's car out on the freeway and red-line it now and then, say's he needs to blow the carbon out of it. It worked...

So, Grandma, just twist hard from time to time.

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Hey now!!

Yeah I've heard this before, my friend has a ricer and he swears by redlining it from time to time to keep it clean. He said when he took the heads off it was clean as a whistle.

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weekend trails rider, low rev low speed technical stuff

Take the bike out to an open field and practice drag racing it. Go through all the gears and bring it to redline at shifting. These bikes will have excess carbon build up quickly if you are using it for trials and slow technical stuff.

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yeah i never thought of that.. I've been using 93 from a new local texaco. of course idk what the last owner used

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