I just bought a 2002 sv with 4600 miles and it backfires alot when I let off the gas.I tried some seafoam but haven't emptied the tank yet.

If this is a new condition and you've not worked on the bike recently, I'd try a dose of StarTron in the gas tank. It will eat the sludge that grows in fuel systems exposed to gasohol. Put it in the tank, ride a few miles to get it into the carbs, and then let it sit overnight. It has special enzymes in it that do the job. Seafoam is a good product but is not designed to clear bacterial sludge.

Check the fuel filter for a clog or the MAF sensor.

Sounds like you need to have the carb jets cleaned. You can try seafoam that you add to fuel tank and ride it to see if that will clear it up, but I have had the same problem with my VF750C Honda Magna with only 8000miles and mine turns out to be fine tuning the injectors. This is only after the carbs have been reworked and cleaned.

Carbs are probably gunked up. Buy a can of Seafoam (Walmart, Auto parts store). Put half the can in the gas tank and fill it with gas. Next tank, straight gas. Third tank, other half can of Seafoam. This should help desolve the gunk. Do this every spring with my Goldwing.

hi putting seafoam in fuel will clean the valves and pistons over time to use to do lifters you need to add to oil measure out the right amount for the oil measurements on the can.. also the tapping is it more when its cold or just the same no matter hot or cold or is it more louder when hot. when was the last time the timing was checked, are you using 5w/30 or 10w/30 oil.

DO NOT USE SEAFOAM IN BRAKE RESIVOIR!!!!! That being said it can go into the gas tank and the oil. Use 1 can of Seafoam in the gas tank. If you are going to change the oil soon you can use 1/2 to 3/4 of a can in the oil. Make sure to change the oil in less than 100 miles. Seafoam thins out the oil and if it is in too long can cause some parts to not get oiled enough. Good Luck!

I had the same problem with my 98 Corvette with 69K miles. Mine did exactly as you described soon after I purchased it in November of this year. I went online and read posts of others with the same problem and how to try and fix it. At 1/4 tank add 2 bottles of Chevron Techron cleaner and fill up with good name brand premium fuel. The Techron cleaner will clean the sulfur residue and other contaminants off of the fuel level senors in each of the left and right hand side gas tanks (C-5's have two gas tanks on either side connected by a transfer pump with each side having it's own fuel level sensor). I did this and so far after nearly 3 tankfuls there's been no recurrence of the problem. However, if this doesn't help then the alternative is to replace some if not all of the components mentioned earlier. I got a $1300+ repair quote from my favorite garage prior to applying the above fix. I'm no mechanic and I may have some of the actual part names incorrect. I hope this helps you out and fixes your problem! BTW, you can also use a full can of SeaFoam cleaner in lieu of the Chevron Techron cleaner. I used the two bottles of Chevron Techron the first tankful and used SeaFoam in the second tankful. I plan to use a bottle of SeaFoam every 3-5K miles to help keep this problem at bay and keep my fuel system cleaner!

do a search on GM sulfur and fuel sender problems. Your not alone. The fix is to remove the gas tank and replace the sender

Run some Seafoam through the carbs. Should be available locally at a parts store. Mix with your gas according to directions. This will clean out the carbs, which sound like they are a little gummed up.