Motorcycle Repair: Hard starting, suzuki rmz250, leak down test

Question
Hello Mark,
I have an '04 Suzuki RMZ250. Recently it has become hard to start when it is cold. I have put in a new plug but it didn't seem to have any effect. The last time I went out the only way I could get it to start was to hold the throttle wide open. Once it was warm though it started fine. It also backfires and shoots small flames out of the exhaust every few kicks. Do you have any ideas?

Answer
Hi Don,

Learn to about reading the spark plug: www.ngk.com "Plug 4-1-1" section.

The appearance of the plug will tell a tech what's ocurring during the combustion process and about the air-fuel mixtures of the carburetor.

Measure cylinder compression. Perform a leak-down test if compression readings are out of service limits.

Check the condition of the air filter. Clean or replace accordingly. Same with the spark plug.

Check and adjust valve clearances.

Basically, perform a complete service (tune-up). If the problem persists, advise. We can go from there.


Respectfully,
Mark Shively