How can you tell if your bike is running lean?

How can I tell if my bike is running lean?

It seems to be running hotter lately.

How can I adjust or compensate for this?

1978KZ650B

Need some details on your bike.
Stock pipe...carbs...pods or airbox?

Have you been inside the carbs?If so,what jets are in there?
Have you checked the plugs for colour?

More details...

Loosen the plugs when the bike is cold, then just barely snug them up, start the bike and let it idle till it's off the choke (fuel enrichment circuit to be precise), and when teh motor gets good and warm shut it off. Remove the plugs and look at them, white = to lean, black = to rich, brownish tan = just right. That checks the idle circuit only.

To check the midrange, ride down the road at around 30-40 mph using minimum throttle to maintain that speed, after a couple of minutes squeeze the clutch and hit the kill switch at the same time. Pull over, remove the plugs, and look again, same colors as above.

Now comes the fun (and highly illegal on the street) part

Ride down the road at some reasonable speed, open the throttle wide open and hold it there for a minute or two, then do the clutch and kill switch thing and coast to a stop. Check the plugs again.

The above procedures will check mixture at idle, midrange, and WOT.

Fortunately, I live on a State Highway in a rural area so I can do all the above and coast into my driveway, if you live in a residential area in a larger city then I suggest you carry a spark plug socket and ratchet in your pocket and find you a rural area where you can do the plug checks on the side of the road.

But Officer! I was just trying to check my fuel mixtures so I don't burn my bike up! Honest!!

It is normal that a bike's operating temperature is higher in the summer than in cooler times of the year. The bike is air cooled and the outside temp affects the bike's temp quite a bit. Pull your spark plugs and unless they are pretty white colored, I wouldn't worry about it...

If its a hot day then the engine will get, look, and feel hotter. If the fuel mixture has been good in the past {in cooler weather } then hot days don't really change the mixture.
The full throttle check is best done under load as well, like up a long incline. And thats for ajustment for your main jet, and that the main jet you should have right:laugh:

Actually, if the outside temp is really high, it tends to lean the air/fuel mixture. There are charts out there for altitude jetting and the one thing they all have is a temperature compensation index.