bike ran great until today

[81gs450l]

i have a 1981 gs450l it use to run good. then today i took it out and it smelled like pure gas coming out of the pipes. it bogs and dies when cold. once it warms up it acts like it doesnt want to accelerate like it use to and it smells overly rich. i havent added or changed anything since the last time i rode it, which was 2 days ago i am kind of stumped.

 

[platinum2]

does it have a diaphragm on the fuel tap? it might be blown,tap on the float bowls with your hand see if it helps, the floats could be clogged with dirt

 

[Guest]

Have you checked the oil to see if it's over full and/or smelling of fuel? If so, your fuel tap could be buggered and leaking, diluting your oil with fuel.

Did you leave it on Pri for those couple of days?

 

[oldrookie]

Sounds like mine did when the needle was sticking in the down position.
Can you tell of it is both cylinders...or just one?

 

[81gs450l]

i have tomorrow of work so i am going to look at the bike. the only thing i did different was keep the bike in the bed of my truck for a week. Come to think of it i did smell gas a few times from the bed of my truck when i walked by it

 

[oldrookie]

If both are loading, could easily be the petcock.

If one, check the needle. Mine would run if I pulled the left spark plug wire. In fact, it made no difference to the way it was running. Stalled as soon as I pulled the right one. Left was just flooding out.

 

[81gs450l]

latest update. i went to fire up the bike today. it ran decent at idle. i hopped on it to take it around the block and it didn't want to accelerate even through the apartment complex.i limped it back into its parking spot stal;ing out about 3-4 times. i put the bike on the centerstand and its throttle response had no lag or stumbling. i ran it through 1st to 3rd gear and it ran strong. I put it back on the ground and twisted the throttle. Of cours the bike staleled and died. The oil smelled good, no smell of fuel. any thoughts are appreciated. I have a week to get it running right so i can take my truck in to get the hail damage fixed.

 

[Guest]

Hmmmmm... how's your charging system? Plug colours? Have you checked float height in the carbs to make sure she's getting enough fuel? I'm not sure off the top of my head what would make her bog down and stall under load yet run fine with no load other than not getting enough fuel...

Have you got a fuel filter between the fuel tap and carbs? They've been known to be too restrictive before...

 

[81gs450l]

i have clear fuel lines from the tank to carb and a clear fuel filter in between. i can fuel flow through the lines. i havent pulled the plugs to check them that was my next stop. i can smell gas fumes coming from the exhaust also. i think when i get some time this sunday i will pull the carbs and fuel tank and start there along with checking the charging system. the only other issue i notice was my throttle cable was loose.

 

[Devon]

I'm going to stay tuned to this thread as it sounds exactly like what my 1980 450L does from time to time. I hope the below info doesn't read as a thread takeover, just extra information that may or may not be helpful or related.

On mine, I have done the full GSR-approved complete carb disassembly and dip in Berryman's for 24h and new o-rings from Robert Barr. Float heights were set with a digital caliper. Valves adjusted less than 1500 miles ago.

If I start the bike up from cold it will idle and warm up normally. If I then immediately start riding all will be well with no issues whatsoever. But, if I start and warm up the bike, then get stuck in stop and go traffic, or shut down and restart the bike before I've ridden a few miles, I'll have the same bogging and rich issue.

With mine, this issue only affects cylinder 2 (pull that plug wire and no change, pull cyl. 1 and bike dies), and it will resolve itself if I ride steadily at about 1/4 throttle for about 1/4 - 1/2 mile. Suddenly cylinder 2 will start running normally, and again all will be well until the next cold start. I've always suspected a sticking needle in that carb, but no amount of banging on it will affect any immediate change.

 

[Guest]

I'd probably suggest double checking your main jets are correct too... 115's from memory.

 

[Guest]

Letting it sit in the bed of your truck was most likely like putting it in an oven. I think I would start with the carbs. Sitting anywhere for a week without running is bad enough with the bad quality of gas these days.

 

[oldrookie]

I'm going to stay tuned to this thread as it sounds exactly like what my 1980 450L does from time to time. I hope the below info doesn't read as a thread takeover, just extra information that may or may not be helpful or related.

On mine, I have done the full GSR-approved complete carb disassembly and dip in Berryman's for 24h and new o-rings from Robert Barr. Float heights were set with a digital caliper. Valves adjusted less than 1500 miles ago.

If I start the bike up from cold it will idle and warm up normally. If I then immediately start riding all will be well with no issues whatsoever. But, if I start and warm up the bike, then get stuck in stop and go traffic, or shut down and restart the bike before I've ridden a few miles, I'll have the same bogging and rich issue.

With mine, this issue only affects cylinder 2 (pull that plug wire and no change, pull cyl. 1 and bike dies), and it will resolve itself if I ride steadily at about 1/4 throttle for about 1/4 - 1/2 mile. Suddenly cylinder 2 will start running normally, and again all will be well until the next cold start. I've always suspected a sticking needle in that carb, but no amount of banging on it will affect any immediate change.

I'm not sure which carbs you have on your bike. Mine has Mikuni 36's.
If it is your float needle, banging on the outside won't help. The float needle has a center post that is spring loaded. The float sits on top of the spring loaded part. The needle sticks down, the float doesn't work properly and too much gas enters the carb and cylinder. The cylinder floods out and the symptom you describe begins.

Any backfiring? Smell of gas? Gas in the airbox?

 

[81gs450l]

no backfiring, but i when the bike was in the bed of the truck i could smell gas fumes. when i fire it up and have it running the exhuast smells almost like straight gas fumes. i am not running an air box, the bike has K&n pod filters

 

[81gs450l]

i pulled the spark plugs today. when pulled the right plug it looked ok and no smell of gas. i pulled the left spark plug and it was wet and smelled like gas. when i started looking at the plug wire i realised that the boot wasnt making a good connection with the wire itself. so i need a new wire for the left plug. i am thinking i will just do new coils and wires. anybody know where i can get new coils and wires?

 

[koolaid_kid]

If you have the type of boot that screws into the wire you can trim the wire by about one half an inch and get to fresh copper. This works most of the time.

 

[oldrookie]

I'd spend the few dollars for the boots first. Might solve the issue for under $10.

Coils get a bit pricey.

 

[81gs450l]

the wire looks like its been trimmed before by the previous owner. if i take anymore off the wire it may be to short.

 

[Guest]

I just had a thought... have you had a timing light on it to make sure both sides are firing properly?

 

[81gs450l]

i havent had a timing light on it, but i pulled the plugs and the left plug was wet an smelled like gas. the right plug has no smell of gas and was dry. thats when i discovered the left plug wire was messed up. is there anyway to just replace the wires or do i need to replace the coils and wires? where can i find the replacement parts.