Took my mc28 for mot today, noticed the left pipe wasn’t smoking ? The fuel is old as I imported the bike from Japan and it just arrived having been purchased in September. Both exhausts hot to touch..

Any ideas?

I'd probably check plugs to make sure they are both similar in color.

You using premix or the oil injection pump? Oil injection has a hose going to each carb. Might be worth while making sure oil flowing in both hoses if you think one side not getting enough oil.

If not an oil issue, one carb could be dirty resulting in one side much leaner. Plug check might give some indication.

Bottom line, if your concerned, don't go out and get yourself hurt on the road.