1st Valve adjustment was a success!

[bigfour]

... and it was easy too. Intakes were fine, Exhaust valves were too tight. Now my bike idles perfectly, I used to have to keep the choke on for at least a minute after starting so the engine wouldn't die, now the choke can be turned off after 20 seconds, even in chilly weather.

BTW, I pointed a flashlight in the spark plug hole just out of curiosity, and the top of my piston, was completly covered in black, carbon deposits I suppose (my spark plug was a light tan though). Is this normal? I didn't expect a pristine glimmering piston, but a didn't expect a pitch black one either. It's a 4000mi bike BTW.

[Dupo]

Light tan on the plug is good. I would imagine the carbon deposit is just as normal.

I really need to do a valve adj on my shadow..... one of these days lol.

[jnortonsr]

I too have to increse the choke, throttle in cold weather. I also start it while sitting on it and put on my helmet and gloves. Otherwise it will die for for the first couple of minutes. How hard is this adjustment?

[Badbob]

Engines need a bit richer mixture when they are cold. That is what the choke is for. Needing a little choke to idle while its cold is not a malfunction.

Having a single cylinder air cooled engine the GZ250 is a bit temperature sensitive and is not very tolerant of misfires. If the engine is not up to normal operating temperature and you push the choke to the off position the mixture will be leaner, the idle speed will be slow, and the chance of misfire higher. If it misfires the engine will stop.

The colder it is the colder the engine runs. If you ride in cold weather (below 40) you may notice that the idle speed tends to fluctuate with the temperature.

Not changing the spark plug at the prescribed intervals may also increase the number of stalls when the engine is cold.