Head off.

[Lilduke88]

So I took the head off after the smoking on the ol girl started getting worse and it looks way better than I ever would have imagined. The piston side is really clean, hardly any Carbon and none on the piston tops. The valve side is another story. It’s pretty black and most of the valves are covered with carbon. I put sea foam in the cylinders and it didn’t leak through so I’m assuming the rings are good ish. Do I need a valve job or what’s the general consensus. Thanks.

[inairam]

I read once on this forum "there is not a Cub out there that does not need a valve job." So yes you need a valve job and since the head is off why not. Do you have any photos? of the head, head gasket and the carbon on the valves. Pictures will help tell a lot.

This is what i found when I pulled the head off my 49. viewtopic.php?f=1&t=93111&hilit=valves 2 years ago. I did not replace the valve guilds but I did get the head milled and the new valves ground. I recovered power and reduced but did eliminate smoke but it was done quickly and for a few hundred dollars.

With the head off you want to take advantage and flush the block thoroughly. many post on this.

[ricky racer]

Smoking is not a valve issue, it's an oil burning issue. Oil burning is generally caused by worn rings and or a worn bore. While the head is off, I suggest you measure the bore to see if it is within spec. Ring end gap is hard to measure while installed on the pistons in the bore. Pulling the pistons from the block, removing the rings and placing them in the bore is the only way to really measure the ring end gap. If the cylinder has a ridge at the top of the bore, it's probably in need of a bore job. Remember, there's no Cub out there that isn't 50 or 60 years old so you've got to expect some wear.

[jsfarmall]

Yeah smoking is a very good indicator of oil coming by the pistons. Valves never hurt to be replaced. At least lapped especially having alot of carbon. Doing a ring and valve job is pretty quick and easy for in frame.