Hi. I have a 250 v star i put a new set of plugs in it the motor bike shop gave me plugs that were 1 degree colder the original ones were CR6HSA, but he gave me CR7HSA he said it shouldn,t make much difference, try them and see how you go, but i have now noticed when you back off on throttle when its cold it will back fire but runs perfect when its hot, can anyone shed some light on the subject, would it be because i have choke on plug is one degree colder that;s why it will backfire when you back off on throttle when cold.

If it didn't have this problem with the other plugs...put the old plugs bag in. What did the old plugs look like when you took them out?

I went to start it one day and it wouldn't start, with old plugs but as soon as i put new ones in it fired up , i will try some new plugs the right type and see how i go