Thunderbird 900 Misfire

If all you have done is drain the carbs and refuelled then my guess (for that is what it is, but is what I would check first myself) would be that you have disturbed some muck in the carbs which is now seeking revenge on yourself by giving your bike some sort of indigestion. May be worth draining the left - and possibly the centre - carb(s) again. Daft as it sounds, it may even clear itself if you are really lucky - but don't hold your breath on that one!

 

Is the misfire present all the time or when you load engine. All cylinders running at idle?

 

That sounds like it could be a stuck float / needle causing a bit of flooding

 

I would agree, the fact that you have black smoke & flaming would suggest one of the carbs is pouring in excess fuel. You could try tapping each carb float bowl , a long shot but worth a go. Then unfortunately sounds like carb strip

 

You have by drawing the carbs allowed the floats to drop to their lowest level. May be one has not popped back up, hence the tap tip

 

Dirt / grit on float needle seat, more likely the float needle hasn't settled back properly when re-fitting the float bowl.

As Ken has just suggested tapping the side of the carb around the floatbowl with the plastic handle of a decent sized screwdriver may just settle everything back, but its a longshot and will probably mean the floatbowl being removed and refitted taking care to ensure everything is spotless and back in place.

If the carbs had gone dry sometimes the needle tip drys out ( if its a rubber tip ) and becomes softer and seals better once its been soaked in fuel for a time.

 

check pilot jets are clear. only way is to push copper wire through. Air or even ultrasonic won't do as the hole is too small, copper will not harm the brass jet. Also check o rings on the float valve.

 

My favourite is Redex - but use whatever you can get ... every little helps, as the old lady said as she peed into the sea (one of me mum's favourite sayings - very wise was my mum!!).

 

lol did she use redex as well?

I use redex every other fill up in my Sprint, it has made the bike run and idle much smoother, tho it took a few tankfuls to get where I am now.

 

I couldn't possibly comment!

 

Glad youre sorted, keep that screwdriver hand till you've done the strip and clean

 

Keep using additive but otherwise leave alone (if it ain't broke / don't fix it)