Quote Originally Posted by Pfaelzer View Post
I changed the original Chinese spark-plug against an Iridium alternative, which promises that the engine runs better on low rpm.


...back to overview.
Just looked up the maintenance manual of JH600 from Jialing and found that the recommended plug is CR8E. Is there a reason why you selected CR7E instead?
(Don't know much about spark plug, but my Google search results mentioned something about the fact that CR8E is a "colder" plug. Does this have anything to do with your choice?)

By the way, all write-ups about spark plug want the plug "properly gapped" before installation. Is the new plug likely to need adjustment in its "gap", typically?

Cheers.