Im having a backfire issue with my 02 620. The issue happens when decelerating around 5000 rpm... i put new ngk DCPR8EIX iridium plugs in a few weeks back and im concerned they maybe been too hot... the problem is it never backfires in cold weather but when the temperature gets above 50 degrees it starts every time i slowly decelerate. I am not really sure if it could possibly be an exhaust leak... a fuel remap, or a valve adj... i am over 200 miles from my nearest dealership so i would like to get a good idea what it could be
impossible to tell without looking at your bike and it sounds like you have an idea what it could be.
do you have the old plugs? brush them off and stick them back in and see what happens.
yes that was the plan but its been raining for days and i cant get the bike out... any ideas why it would only do it in warmer temperatures?