Motorcycle Repair: backfire through carb, yamaha tdm 850, lean condition

Question
hi i have a yamaha tdm 850 1998. the bike is backfiring through the right hand carb.plugs,air filter ect been replaced.

Answer
Its possible that the carbs need adjusted.As the bikes age and miles and useage mount up the linkage wears and the carbs need syncronized. It sounds like you have a very lean condition on this carb and cylinder. Do few things first that wont cost alot. Put fresh spark plugs in gapped at about .028 make sure intake system is complete. Start bike bring RPM up to about 4000 rpm then shut off and pull plugs. If this cylinder still shows a plug read a little lighter the the others its still to lean.If they look the same do a compression test.If this cylinder shows a little low add about 3 squirts of oil and try the test again.If it doesnt change you may some tight valves and the compression is leaking back into the intake. You may need to adjust the valves then.