Beautifu sight!

Just saw one of those big name, high dollar ($1700) modified cylinder heads for a 250F. It had the improved 1 piece valves, bronze seats, springs, etc.

The seats hung out into the ports on the back sides. So much for "porting". One of the exhaust valves had broke and the piston tried to shove it thru an intake, then thru the head itself. It ran a total of 5 laps at a local track. Only good for a conversation piece now. I guess I will stick with stock parts a little longer!

My stock parts are still working great! Actually I replaced the valve springs, but the valves themselves were still good after one year.

What type air filter and filter oil are you running? What proceedure do you use to clean the filter? Is the bike ever ridden in very dusty conditions? I am thinking the valve trouble we have had is related to very fine dust making it past the filter. The air box has been resealed at the screen and the recall on the screen done but I still see ugly areas in the top of the carb when I remove the cover to change needle positions.

i just replaced my stock valves on my kx250f and it runs great but i think my stock valves were close to breaking because i just broke one in my hands "im 16 years old"

I run No Toil oil and filters, and as for dust, most of the time it's not very dusty so I'm sure this helps. I did reseal the air box/boot. Nothing special really. Good luck.

Thanks .

YOU ARE CORRECT, much of the valve problems concernning these bikes is due to dust making its way into your top-end. Knew someone who had the same problem, I spoke with a mechanic at team green and thats what he said. SILKOLENE makes an awesome air filter oil. Goes on like water yet becomes the stickiest thing ever by being worked in.

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