gs850 MISS FIRE!!!

[nisom512]

So I have a 1981 gs850l and have tryed everything to get it running right. but it still has a miss fire on cylanders 2 and 4. I know this because the pull the plug wire and the rpms do not drop. I can take both of thos plug wires off and the rpms dont drop a bit. I tested the spark plugs by pulling them out and and turning the engine over to see if I had spark and it is a fire works display of sparks.

the list of things done to get the bike running.

-Thouroly cleaned carbs (diped, o-rings, intkae boot o-rings)
-new battery
-coilrelay mod
-dyna coils and ignition
-sparks
-it has a uni air filter
-tested plug wires by swapping the wire to the other coil and didnt change a thing.
-compression 125-130psi
-rejetted to match the uni intake and exhaust(4-2)main(122.5)pilot(42.4)
-valve clearances
-the #2 plug is soaking wet when I take it out.

There is fuel pouring out the left exhaust almost.

if I remember something that I forgot later I will add it.

Please help me I am at a huge loss now. and none of my michanic buddys have anything else to try.

Thank you
Jake

[ryonker]

Yeah;

Jake and I have been working on his bike for a while (mostly him, I have helped a little). It was doing this running on two cylinders thing, so he came over to my house last night and we dipped all his carbs for an hour and really blasted them out with carb cleaner then major blasts of compressed air.

So we are stuck. New coils, new ignition, good plugs, got gas, clean carbs, new air filter, valves clearances all in spec. So now what?

Rick

[rustybronco]

see if you have fuel in carbs 2 &4 by loosening the drain screws.

There is fuel pouring out the left exhaust almost.

what do you mean by this?

did you bench sync'd the carbs when you assembled them?

does it run on all fours at a higher RPM?

[ryonker]

see if you have fuel in carbs 2 &4 by loosening the drain screws.


what do you mean by this?

did you bench sync'd the carbs when you assembled them?

does it run on all fours at a higher RPM?

I am pretty sure they were NOT bench synced. Will that cause these issues? Visually, they didn't seem off by much but I know it helps to use a little wire or something consistant in the intake and exhaust of the carbs.

Rick

[nisom512]

see if you have fuel in carbs 2 &4 by loosening the drain screws.


what do you mean by this?

did you bench sync'd the carbs when you assembled them?

does it run on all fours at a higher RPM?

there is fuel going to cylanders 2 and4 I know this because there is a lot of white smoke(raw fuel) pouring out of the left exhaust I have a 4-2 so this means one of the cylanders #1 or #2 is not firing. and two because like I said when I pull the plugs after running it they are wet with fuel.

did not bench sync the carbs it but is started and ran just fine this morning just cyclanders 2 and 4 didnt run.

I am pretty sure that cyclander 3 runs at a higher rpm when I drive it around.

keep em coming.
Jake

[rustybronco]

I would suggest at this point, you try whacking the float bowls with a screw driver handle and seeing if you have stuck floats. I suspect you will have to take them apart again and check the floats and/or levels.

***edit*** also check for a cut o-ring(s) on the float valve seat.

[Nessism]

Did you guys remove the pilot jets and poke a wire though them to make sure the orifice is open? Another thing is that if your petcock has failed it may dump fuel down the vacuum line and into your #2 carb. Try installing a piece of clear tubing in place of the black vacuum hose leading to the petcock so you can look for dumping fuel.

[nisom512]

So I thought to my self a little bit ago and said ya know what screw this I just want to ride this thing. so I start it up and drive it a bit and I can see the trail for a long ways behind me of white smoke(raw fuel) and I just keep going I start getting on her a little more and more at a time until eventually to my surprise the smoke gets less and less and the thing gets fatser and faster. so I think what the crap?!!! and just again think screw it im gunna keep going so I do and now she runs like a champ. no Idea what was wrong with it and I dont frankly care at this point I just am happy I get to drive it. thats me right now.

Thank you guys for all your help with all my threads

JAKE

God bless

[nisom512]

Did you guys remove the pilot jets and poke a wire though them to make sure the orifice is open? Another thing is that if your petcock has failed it may dump fuel down the vacuum line and into your #2 carb. Try installing a piece of clear tubing in place of the black vacuum hose leading to the petcock so you can look for dumping fuel.

that is what was happening because I was just riding it and all the sudden I lost power in the middle of an intersection. and then it wouldnt really start. so I turned it to prime and the thing started right up. and ran great so I now know the pet cock is bad too.

jake

[bonanzadave]

Im guessing you had some crap in the carb causing a needle valve to stick open. Taping on the float bowl probably wont help that. Dump some seafoam in and keep riding......

[jjmaag]

Check the float levels again. I had one carb that leaked fuel after the carb rebuild, all were set to the low end of the float height limit with new needle and seat assys. I reset the levels to the higher end of the limit and the problem was solved.