The riding season is passing me by!!!

[Brown Bomber]

I am in dire need of some guidance. I have a 81 GS850G. Problem: One and three are not firing. It does idle steady on 2 and 4 around 1500. It has done this since I have had the bike. The spark plugs on 1 and 3 are wet and smell of gasoline. This is everything I have done to the bike so far. I have replaced the o-rings to the carbs. Bench aligned the carbs. I have replaced the cylinoids. I have checked for sparks...there are sparks (this sent me to the hospital once a few years back...lesson learned). I have checked the float height and they seem to be within a millimeter of each other (this was not with a digital caliper). Compression of all 4 cylinders is around 140-150. I have also replaced the stator and rectifier. I do have a mystery green striped white wire and red striped white wire from this replacement. I was blowing head light fuses like roman candles before I replaced the stator, and sent all the stator wires to the rectifier. This has since been able to solve the fuse issue. Did I do something weird to the ignition system? I am just baffled about what to do!!! I feel like I am really close because I am running out of parts to replace!!!!Any help would be appreciated.
This forum is awesome by the way. This is my first mechanical project. I never would have made it through the carb cleaning without the training wheels provided through this forum.

 

[SqDancerLynn1]

I would start by replacing the spark plug boots & make sure you have 12 V on the coils

 

[Brown Bomber]

Thank you

Thank you

If spark plug boots are what the spark plugs plug into, then they have been replaced. I will check the voltage tomorrow. Thank you for the reply.

 

[duaneage]

After you check that proceed to the right side of the engine and remove the DOHC labeled cover and see what the pickup coils on the crankshaft look like. It could be there is a lot of water or junk that damaged them.

Next stop is the ignitor box, this triggers the coils and while they are very reliable they are not foolproof. Check all wires connected to this box, especially the blue and green wires from the pickup coils/


Here is something to check, make sure the ignition coils that feed 1 and 3 are secured tightly and that the screws holding them down are not corroded, painted over, or loose. This can cause problems with firing since the secondary of the coil needs this ground to complete the circuit to the spark plugs. The plugs are screwed into the engine and this forms a path up to the coils where the mounting screws act like wires to complete the loop. 25,000 volts has to flow through the coil wire into the top of the plug, but the voltage has to get back to the coil somehow.

Don't handle a loose coil with the engine running or your liable to get zapped.

 

[Brown Bomber]

Thanks again

Thanks again

I did check the crank case. Everything seemed to be fine. There is 28,000 miles on the bike. There was no noticible pitting on the two contacts for 1,4 and 2,3. The inside looked brand new/undisturbed.

 

[duaneage]

Are the mounting bolts that hold the coils on the frame under the tank in good shape? Are they loose or corroded? If you remove them and clean off the surface real good that might be it.

You can measure the coils too. The spark plug side is around 5000 ohms, the other side is about 3 ohms. You can get an idea of how much they step up 12 volts by that ratio of one side to the other.

try swapping the 2-4 coil for the 1-3 coil, if you move the problem then the coil is at fault. If 1-3 still does not work it is either the igniter, the pickup coils, or the wires between these three devices.

 

[tkent02]

Doesn't one coil go to 1-4 and the other to 2-3 on this model?

Something wired wrong here?

 

[bwringer]

Doesn't one coil go to 1-4 and the other to 2-3 on this model?

Something wired wrong here?

My thoughts exactly.

It sounds like someone was looking at an old Chevy manual instead of a Suzuki manual.

1-4 are on one coil, and 2-3 are on the other.

 

[Brown Bomber]

yep

yep

That is why I am baffled!!! 1 and 3 are not working, yet 1,4 and 2,3 are supplied by the coils respectively. I can't imagine that one wire out of both coils is bad...and I have checked for sparks and they are present. I will check the voltage going in. I have swapped the plugs that were not working, thinking maybe the firing order was backwards on just those two because the other two were firing. That did not work. I switched them back. ALL FOUR HAVE STRONG SPARK. Are the carbs so sensitive that they are the problem?

 

[joshua]

back to the top for a guy that still needs help

 

[Guest]

That is why I am baffled!!! 1 and 3 are not working, yet 1,4 and 2,3 are supplied by the coils respectively. I can't imagine that one wire out of both coils is bad...and I have checked for sparks and they are present. I will check the voltage going in. I have swapped the plugs that were not working, thinking maybe the firing order was backwards on just those two because the other two were firing. That did not work. I switched them back. ALL FOUR HAVE STRONG SPARK. Are the carbs so sensitive that they are the problem?

strong spark and fuel getting to them at the right time = engine running on ALL cylinders :-s

carbs sure are sensitive but as long as they are clean and all the parts are there you should get all cylinders fireing