Why "spare spark"?

[Rob S.]

Can anyone elucidate the "spare spark" arrangement? My Haynes manual ("4-valve Fours, 998, 1075, 1135cc, '79 to '88") states that,

"Two ignition coils are fitted, each coil firing two plugs in a 'spare spark' arrangement. In this system, plugs 1 and 4 spark simultaneously, combustion occurring only in the cylinder in which the fuel/air mixture is under compression, the remaining spark occurring in a cylinder on the exhaust stroke. The same arrangement applies to cylinders 2 and 3."

Is this for emissions purposes?

Also, is the "transistorized ignition system" in these bikes the same as the "electronic ignition" in current bikes?

Trying to learn.

'82 GS1100e

[sharpy]

For a start get a real manual. not a crappy one. Find one here on basscliffs website..... http://members.dslextreme.com/users/bikecliff/

[SVSooke]

Because it's easier to use 2 separate ignition systems than a distributor.For the second question yeah it's the same thing.

[tom203]

"elucidate" ? not so much of a "spare spark" as a wasted one. This saves money as one coil can fire two cylinders; when #1 is at TDC and looking forward to ignite, #4 is also at TDC but finishing up its exhaust stroke, so firing its plug doesn't do anything- 1 crank rev later they switch roles. Same for 2 and 3 cylinders.

These old critters have a simple electronic ignition system- an ignitor duplicates what points do (close and open)

[hampshirehog]

The usual term is 'wasted spark'. In these bikes the pistons rise and fall in pairs (1&4 and 2&3 are the pairs). However, while ,say, 1 is on the compression stroke 4 will be on the exhaust stroke (the upward movement of the piston is pushing the exhaust gases out of the engine via an open exhaust valve). At the top (actually a little before the top) of the stroke both plugs will fire - 1 is igniting the fuel/air mix and the other achieves nothing (it's wasted). Makes for a simpler ignition system.

Your assumption about electronic ignition is correct ( though electronics have moved on a bit since the 70s)

Sharpy is right about the manual.

[Rob S.]

Haynes no good?

Is it so that the Haynes "Owners Workshop Manual" is not up to snuff?

I went to the '82 1100e manual on the Basscliff site; it seems to be an online manual, not an old style book I can buy and leaf through with greasy hands.

At this point in my life, I'm not looking to save a few pennies, so I would spring for another manual. On the other hand, I haven't done anything more myself than adjust the drive chain. I leave the work to my local shop. I just like to read the manual to try to understand what makes my Suzi tick.

I just did a search, and could not locate an '82 1100e Clymer.

[SVSooke]

If you want a hard copy just print it off.I do that with pages I need.Found it's just as easy to go to the download on my commuter most times.

[Killer2600]

The wasted spark ignition is purely for simplicity sake. A 4 coil system (one coil per plug) or a distributor system could have been designed for the bike but it over-complicates and adds excess cost.

Emissions? When these bikes were new emissions was in it's infancy. The only emissions on these old bikes were caps on top of the fuel mixture screws to prevent tampering with fuel mixture.

[Rob S.]

No jack

Yes, printed out a few pages already. And it appears to be the official, original Suzuki service manual, as opposed to the Haynes, which is a Brit mechanic disassembling and reassembling accompanied by a photographer.

Already found a little discrepancy between the two. Suzuki says to jack up the front before measuring fork air, while Haynes just says to hook up the gauge with no mention of jacking. I know it's not Electrical/Ignition, but any ideas on how to get the front wheel off the ground without a jack?

If the bike ('82 1100e) had a center stand, I would just have someone sit on the rear of the seat. As it is, I just tried lifting the front wheel (it's on a rear "paddock" stand), but no luck. (Looking at where the stand lifts the swingarm, I see that's pretty impossible.)

If I was in sunny Green Bay I'd be out riding, but as it is I'm stuck in the snowy Big Apple. I appreciate all you guys helping this old man get back on two wheels.

[sharpy]

Or you can scan Gumtree or simular sites for a el-cheapo computer and put it in ure man cave with manuals and music on it. Works a charm

[twotimeGSr]

I like to think of it as an "after-burner"

[tkent02]

Actually it doesn't, it just makes twice as many sparks.

[bwringer]

If you've got the usual four-cylinder firing order embedded in your brain, as used on cars with distributors...

Just be aware that, um, it doesn't work so well when hooking up the wires on your GS.

Guess how I learned this long ago and far away.

[gs11ezrydr]

The wasted spark as I have heard it called is supposed to burn off any excess unburned exhaust gases. Clearing out the cylinder for the next clean fuel charge. Since it's not under pressure and only unburned hydrocarbons are left over. Seems to be an emissions thing. Just makes for a cleaner exhaust emission. I do stand to be corrected though

[trippivot]

the wasted spark event is just an after effect of simplicity. and by simple I mean directly off of the crank - not a gadget reducing ignition to 1/2 speed and sparking once every other time .

Running the ignition directly off of the crankshaft and a full combustion cycle taking 720 degrees or 2 revolutions of the crank, makes a spark during overlap that is wasted -

compression and overlap both happen when the piston(s) are at T.D.C. alternating one than the other.