1980 GS850GL Need some advice

[Uncamitzi]

Ok...all back together... and I had a momentary sense of elation ...after getting the carbs back on, and the airbox tightened back on.... I hung my temp gas container, and pulled the choke... set the spark to it and waited for about 4 seconds of crank..and it fired right up.... and purrred in idle.....

so I let it idle for a bit to warm it up... about 5 minutes of idle and then I revved it a bit. dark smoke out of #3 & #4.... ...

When I bip the throttle it seems to flood out. If I increase the throttle steadily...it revs up ... but a bip kills it...

Where am I ?

[Uncamitzi]

Never mind...pulled the plugs and I'm not getting spark to #1 & #4.... back to the drawing board...

[Uncamitzi]

back together, some coil problems threw me out of time today. But I did get things fired back up. Sad to say #3 #4 got all soot covered again after just a short run. I'm beginning to think my spark plug problems aren't carb related.

[jeffgs]

Coil windings qill weaken over time, add heat and they will definately breakdown. Can you switch the coil and see if the issue follows? I can on mine but it is a twin.

Heat and rpm take out weak ignition components and can cause random spark and early or late combustion. It is common to see flames in the exhaust from unburned fuel igniting when you get ignition back

[Uncamitzi]

The odd thing and the thing that makes me not really believe that it's coil related is that #3 AND #4 are the ones ...if it were 2&3...or 1&4... sure.. and I wish I knew why I'm not getting a reading in the secondary coil and the bike still runs...

I'm going to tinker with it a bit more today...

[81GS850]

back together, some coil problems threw me out of time today. But I did get things fired back up. Sad to say #3 #4 got all soot covered again after just a short run. I'm beginning to think my spark plug problems aren't carb related.

How do you get black soot without spark firing?

[Steve]

I was about to suggest that you verify that 3 and 4 are on the proper plugs, but you said some time ago that the engine "purrs" at one time or another. If those two wires were switched, it would not "purr".

.

[Uncamitzi]

All the plugs are firing (after my little solder job)... but #3 and #4 plugs are building up carbon almost immediately after firing. A motor run of only a couple of minutes produces a thick layer of soot (carbon) on both plugs. I did measure the float heights during the first and second reassembly and all 4 were within spec. stuck float? dyno needle valves set wrong? two bad float valves?... that's the agenda today.

[Uncamitzi]

I was about to suggest that you verify that 3 and 4 are on the proper plugs, but you said some time ago that the engine "purrs" at one time or another. If those two wires were switched, it would not "purr".

.

Ok.... that's actually not a bad point to bring up... while I know that 2&3 are on the right coil and 1&4 are on the left coil... does it matter if you are on the right or left HT lead off the coil?

[Uncamitzi]

Progress!! the airscrews take a VERY light adjustment. I just ran for about ten minutes with little carbon build up... with one turn out on #4 ...it's really techy...ain't it?

[81GS850]

Ok.... that's actually not a bad point to bring up... while I know that 2&3 are on the right coil and 1&4 are on the left coil... does it matter if you are on the right or left HT lead off the coil?

Yes it does, but the plugs for the coils to the harness can only plug into their respective coil. Now the wires from the coils should be going to the correct spark plug. Mine are oe and were numbered on the wire.

[Uncamitzi]

Yes it does, but the plugs for the coils to the harness can only plug into their respective coil. Now the wires from the coils should be going to the correct spark plug. Mine are oe and were numbered on the wire.

I don't understand what you are saying there... If you mean that the coil has to plug into the correct 12volt and trigger wire from the igniter... yes..they've taken care of that with the reversed connectors for the most part. however I was asking if FROM THE COIL it matter which lead goes to which plug. Right side coil goes to plugs 2& 3... Left side coil goes to 1 & 4...but are the two leads FROM the coil interchangeable. on each coil you have a right and a left side HT wire to the plug. So for example... Left coil... # 1 & #4.... Left coil left HT lead to #1 Left coil RIGHT lead to #4? Right coil Left HT lead to #2 Right HT lead #3.... or can /should they be swapped?

[60ratrod]

The ignition system is what's called a wasted spark system, meaning that both wires on that coil fire at the same time, regardless of whether or not it's that cylinder's turn to ignite the fuel. Swapping wires is only for trouble shooting, seeing if one wire is bad, ect. Otherwise it doesn't really matter which wire is going to which cylinder, just so long as the wire is going to the correct coil for that cylinder. The important connection is from the wiring harness.

[Steve]

If you compare carefully, you will find that one wire on each coil is a couple of inches longer than the other. That is to account for the offset of the coil mount. Other than that, it doesn't matter which lead goes to which plug. As mentioned, you can swap them for troubleshooting. If you are having problems with just #4, swap the leads from 1 and 4. If the problem is still with #4, your problem is not with ignition. If the problem is now with #1, your problem is related to the wire or plug cap. Just part of systematic troubleshooting.

.

[81GS850]

If you compare carefully, you will find that one wire on each coil is a couple of inches longer than the other. That is to account for the offset of the coil mount. Other than that, it doesn't matter which lead goes to which plug. As mentioned, you can swap them for troubleshooting. If you are having problems with just #4, swap the leads from 1 and 4. If the problem is still with #4, your problem is not with ignition. If the problem is now with #1, your problem is related to the wire or plug cap. Just part of systematic troubleshooting.

.

What he said.