So I picked up a 2006 KFX50, did the typical restrictor removal (exhaust, piggy back, intake, 67.5 main, air box). Still been somewhat difficult to start, and very little bottom end power, still sputters on the top end. But as I started it today, I could see smoke come out of the head gasket, and also some almost foam. I assume my head gasket is toast. I can have the head shaved down .045, I don’t really fear taking the head off, but if I’m going that far, should I go all the way and pull the cylinder off? I’ve got to say, the piston didn’t look the greatest when I had the flashlight in there doing the exhaust.

Is this essentially a beginner job? Do I need to pull the whole engine? I believe I understand the basics, but the last time o touched a piston was small engines class in 98 and I was probably high.
thanks for the advice

Pulled the head this morning, cycled the cylinder, it seemed pretty smooth. Bit of carbon on the combustion chamber. Not sure anything stood out as excessive.

I can say, it’s incredible that this forum goes back to the years before during and after the LTA50. Lots of information stored in there.

i got the .045 number from those archived posts. I’m under the belief at the moment that the head may have a slight warp. I could see the exhaust when cold, seemed to get better when warm. I’m going to take the head to a very experienced shop. I can probe and see what they think.
www.billbune.com

the goal is to have it back together and relatively functional in 2 weeks for the kids birthday, after that I can go deeper if needed. I have to draw the line somewhere I guess. I want the quad to have enough power to move on a limited throttle, and run good enough for the wife or grandma to start.