Motor Guru's please help - 2001 400ex rebuild

[RIDER11X]

Well, I have decided that the time has come for the good ole' 400ex to get a fresh top end. It is running great, with no major problems, other than a minor amount of oil usage, and with approx. 250 hours on it, it is probably due.
I do have some questions, as I have never done this before:

1. Will a simple honing be sufficient on the bore being there are no problems like seizing, or other problems causing this rebuild?

2. Am I correct in thinking a stock size piston will be the one I should select, if only honing is done.

3. While it is apart, should I also change out the cam chain, tensioner, and sprockets at around 250 hours. Or, is that not needed.

4. Is there anything else that I need to check out while I'm in there?

[Rico]

I would have the sleeve to piston measured. My sleeve looked to be in really good shape, TO ME that is. I sent the cylinder, piston and head to GT Thunder for cleaning up and to have a professional look at it. I never in a million years would have thought the sleeve needed replaced but it did, Laz said it was wore out at the top and had scratches..:huh I never seen it and surely don't question his judgement. So I must encourage you to do the same, have the cylinder measured to see if your piston will still work correctly.

If you plan on replacing the piston, get a higher comp one that still runs on pump gas. I think 10.5:1 is the highest you can go on stock bore size. 85mm

I would replace the cam chain with a HD one.