I recently bought a 1999 f4. It does sit outside and the other day it was rainning. I waited until it stopped rainning and went to go ride. The bike started with no problems then i drove down my driveway and it died. I couldnt get it started without holdingthe throttlewide open. Its back firing and black smoke is coming out every time itfires.Ive been toldthe air filter could be saturated or something clogged in the carbs. Any suggestions before i take it up to get the carbs cleaned for $500? Please any input would help. [/align]

 

1st off, why not check your air filter, see if its saturated or just dirty. moisture & humidity can make both paper & sponge filters damp & restict airflow & turn dirt/dust into gunk.

 

So i checked the air filter and its fine. I tried starting it without the filter and still having the same problem.

 

I don't think the rain is your problem. The airbox is under the tank and is pretty well sealed off from the elements.
Backfiring is usually a symptom of a lean condition.How old is your gas? I'm assuming your bike is carbed right? If it is, I suggest taking the tank off and try to start the bike with starting fluid or SeaFoam. Just CAREFULLY pour it straight into the fuel line that you disconnect from the petcock. If it works, drain out all your old gas and start with a fresh tank.

 

Yea its a carbed bike. The gas isnt that old. I filled it last week and it does have some seafoam in the gas already. I think the next thing im goin to check is the sparkplugs. Do you think it could be a bad plug?

 

Yes, it could be the plugs. I would check them, but if that doesn't work I would still pull the tank and try to run it that way.

 

Your on the right track.Black smoke is a sure sign of unburned fuel. It sounds like you fouled a plug. Put in a new set of plugs. go with NGK plugs. stay away from champions.

A few tips to keep from fouling your plugs in the future.

let your bike warm up fully before taking off on it. 145degs is about the ideal temp the bike should be before you hop on and go.

resist the temptation to "rev' the bike when its cold. Again, should be at least 145.

Make sure your battery is nice and fully charged. A weak battery will not spin the engine over fast enough and it will take longer to start, this will lead to fouled plugs as they are getting soaked until the bike starts.

only leave your choke on as long as necessary. usually a minute is all it needs in cooler weather.

 

So i put new sparkplugs in it lastnight and its running but like crap. Its back firing like crazy and i can get it running only by having the throttle open. I dont run it too long just in case its leaning out bad. Any other suggestions? Im thinking the carbs need to cleaned.