All cylenders fire at the same time

[Anonymous]

I have been working on an '82 GS850GL with excessive backfiring. with a timing light, I found that all plugs are firing together. I took out the plugs an grounded them all and obsurved the same when manually moving the pickup. All four plugs fire at the same time with either pickup coil. I checked out the wiring and there is no short between the two ignition coil low voltage signal lines. The pick up coil resistance is on the high end of normal. I concluded that the ignition unit was bad. I replaced it with one from a local salvage yard at $100 and I still have the exact same problem. Is this a common problem with ignitions units? What else could cause this?

Dave

[Anonymous]

I should leave this one alone, but I can't. You must have the fastest eyes in the world to see them all firing at the same time . #1&4 fire together as do #2&3. Are you sure this isn't an air/fuel issue? These are notorious for carb boots cracking with age. Bob

[kz]

Never heared that all 4 plugs fired at the same time, shouldn't be possible by design.

Think it is a carb/carb boots-, ignition timing- adjustment/error or valve/camshaft issue.

I would do some more checking first.

[Anonymous]

I don't think there is any way visually to tell if all four are sparking at the same time. Our eyes don't pick that up. You'd have to be plotting this with something like an occilliscope or something like that that can trace more than one line of data. It just happens way too fast.

I'd be moving towards a lean burn condition myself. This will cause backfires. Also, excessive carbon glowing hot int he cylinders can cause a preignition scenario.

Roger Moore

[Anonymous]

Maybe I should have explained the timming light test in more detail. The timing light is a strobe that fires only when the cylinder with the pickup on it fires. For example, you should only see the 1&4 timing mark when the pickup is on cylinder 1 or 4 plug. The indication is independent of engine rpm.

[nigel]

You can test the igniter box with a simple multimeter.First remove #3&4 plugs,set meter to 1ohn scale,remove plug from ignition pick ups to ignitor box, turn on ignition,now contact the + lead to blue wire and - to the green wire(wires going to ignition box).As the probs touch the #4spark plug should spark and when the prob is removed the #3 spark plug should spark.This works for my `81 1000 so should work for you too.Hope it makes sense.

[kz]

Maybe I should have explained the timming light test in more detail. The timing light is a strobe that fires only when the cylinder with the pickup on it fires. For example, you should only see the 1&4 timing mark when the pickup is on cylinder 1 or 4 plug. The indication is independent of engine rpm.

What are you pointing the timing light at then you test?

Do you point to the same spot on the crankshat for all four cylinders?

Do you have an angle adjustment knob on the stoboscope lamp and is it always in the same positon?

[Don Lobacz]

I get that crossover effect with my timing light too. I think that the idle voltage is strong enough to trigger the strobe from the other lead wire (cheap timing light?). When I blip the throttle, however, I can usually see the correct timing marks.

[kz]

The indication is independent of engine rpm.

Interesting topic, only done that on cars....

I will test on my GS 1150 1984 and come back with what I found out.

I still don't know where to aim my strobe light?

[Anonymous]

Im not sure if this relates, but

Isn't the ignition on this bike electronic. You can not adjust the timing. I would think that the system can not be made to fire all 4 at once. You may be able to check the timing with a gun, but thats all you'll be able to do. As long as the coils and plug wires are not mixed up the thing should be all set.

[kz]

Re: Im not sure if this relates, but

Isn't the ignition on this bike electronic. You can not adjust the timing. I would think that the system can not be made to fire all 4 at once. You may be able to check the timing with a gun, but thats all you'll be able to do. As long as the coils and plug wires are not mixed up the thing should be all set.

Electronics or not, the timing must be set somehow, the only thing is that the springs and pointers are replaced by transistors and contact less sensors or? (and thefore not need adjustment?)

If there is no adjusting possibility on the GS, I can understand your comment (don't know myself)............

That would also be the reason for nobody knowing what point to aim the strobe lamp at, because it's not necessary to do this.

[Anonymous]

ignition timing

You can adjust the timing on the 1980 GS1100E by rotating the stator base if necessary (this bike has electronic ignition).

I recall reading somewhere that some bikes fire on every stroke. I do not think that it would hurt the bike to fire on the exhaust stroke.

Patrick

[earlfor]

Re: ignition timing

Wait a minute! :-) The stator is just an alternator and part of the charging system.(its located on the left side of the engine) I dont see how it could be involved with the ignition timing. I assume you meant that timing could be adjusted by rotating the base plate located under the rotor and ignition sensors that are beneath the right side cover of the engine?

Earl

You can adjust the timing on the 1980 GS1100E by rotating the stator base if necessary (this bike has electronic ignition).

I recall reading somewhere that some bikes fire on every stroke. I do not think that it would hurt the bike to fire on the exhaust stroke.

Patrick

[Anonymous]

ignition timing

Earl.

Yes, under the signal generator cover. I know you all knew what I meant so I erred on the side of brevity.


Patrick

[earlfor]

Re: ignition timing

I kinda thought so Pat, but ya never know when youre going to find there's something you thought you knew but didnt. :-)
Juss checkin :-)

Earl

Earl.

Yes, under the signal generator cover. I know you all knew what I meant so I erred on the side of brevity.


Patrick