Backfires on decell

[weber1]

Hey guys, been awhile. I have been riding my 86 FJ1200 quite a bit. looks and runs great. The bike now has 56k on the odometer. It has a Vance and Hines 4 into one exhaust. My issue is the constant backfires on decell. Can't  find any exhaust leaks, maybe the packing in the muffler is gone. I don't know, it just makes the bike sound cheap. Any ideas? Also, what noises are normal, cam chain noises? Only notice it at idle. The bike is awesome and gets alot of compliments. Thanks to all the advice I have received thru this Forum it is a great ride. Thanks, Rob.

[Dads_FJ]

Has the bike always done this while you've owned it or is it something new? 

[weber1]

Seems like it is getting worse. Bought the bike in the late fall.

[56 CHEVY]

My 86 also did that. A buddy of mine who works at a local bike shop told me to open the idle mixture screws 1/8 turn each and see if that helps. That took care of it for me. There may have been something else going on but it doesn't backfire anymore on decel.

[andyb]

Repack the muffler, it's probably due also.  Won't fix it, but it'll not sound cheap.  Personally I think it's a lovely sound as it crackles.. at night, you can see it shooting small flames occasionally. 

[weber1]

I did a slight carb adjustment, checked the sync. that was good. Noticed idle really wasn't that smooth for a 4 cylinder yet throttle seems crisp and responsive on snap. Took it for a ride and brought it up to 7k for shift points. Awesome ride smiled for an hour. That smile went away the next, when I went to start it, cold air with a smell of gas hit my left leg. Head gasket.

[weber1]

I would like to know if possible if the carb could be the reason for the headgasket problem? Here's the reason I ask. It seems that the number 1 cylinder has fuel in the hole. I had a problem recently with starting and thought it was a battery concern but now wonder if it was a hydro-lock issue. the garage smells like fuel and the blast that hit my left leg was very wet. The bike leans left when on kickstand and wondered if this has ever been heard of. I will check float level, needle and seat.

[fj11.5]

I used to have an early model gsx , that thing used to hydro lock every other day, no center stand due to large single system exhaust , allways flooded number one piston , never blew fuel past the head , but I'm sure it was bending valves when it tried to compress the barrel of fuel , never had the confidence to fix it, or the knowledge, ( depression from birth ) dousnt  help 

[weber1]

Took tank off and carbs. Number 1 cylinder had a lot of fuel in it. Air tested cylinder and rings are washed out and bubbles appear from head gasket when soapy water is sprayed on it. No bent valves. Taking carbs apart tomorrow. When air pressure testing fuel feed hose to carbs it holds pressure when bowls are full. Noticed fuel coming out of small port on carb#1 air cleaner side. I think it should be a quick fix with a new head gasket and the fuel concern fixed.