Help!!! with spark 4

[Guest]

I started sputtering in 1st and 2nd gear. on my way home. My #4 exhaust was warm, not hot like the rest. After check of spark etc, it looks as though spark plug four sparks sporatically, ...spark, spark, spark, no spark, no spark, spark, no spark, spark spark. Also, when the engine is idleing, it runs smooths, thed the tach dips, sporatically, then runs smooth again...right in line with the failing sparl.

So..... I'm guessing it's the plug (which I just cleanded during my troubleshoottin) or the wire. I put a new wire cap on, and the problem continues.

Please guide me with what to do. I really want to ride this week-end. Is this common. Am I going to need to order a part. I hope not..takes too long. errrrrr, just when things were going good.

thanks for the help

[seuadr]

first thing i would do is get a hayes or clymer manual. there are multiple tests in there to help you narrow down the culprit. it could be a coil, or a short in the sparkplug wire. try pulling the boot off, cutting the wire a half inch or so above, and reattaching the boot. use dielectric grease. the book will tell you how to test the coils, the ignitor, and the electrical system. it could potentially be any one of those.

[Outlander]

Since your bike is missing on number 4 cylinder, and not 1 as well, I would say it is the wire. It is either shorting out somewhere, or there is a break in it. I don't think it would be the coil, as the coil controls banks 1 and 4. Since one is hitting fine, I would deduce that it is a wire, cap or plug problem. Turn her over at night, see if you are grounding somewhere, gas tank, cylinder head or even at the connection going into the coil itself.

[maro]

How hard would it be to replace the wire. It looks as though if I cut any more wire off the end of 4, the cap won't reach the plug. Will a local cycle shop carry wires for these bikes.

I'll check my manual tonight, It's with the bike in the garage. I find it best to post here as well as to get multiple opinions...

thanks

[JTsGS650]

Well, at least you know that it's definitely a spark issue. These guys have given you some good advice. I'd make sure that your spark plug cap is on nice and tight. Then clean and regap the plug, if it's still sporadic then replace the plug. If the new plug is sporadic, pull the cap and hold the coil wire 1/4" away from the head and see if it's still sporadic. If it is it may be a bad wire which, are not (easily) replaceable. Then, it may be time to source a good used coil or upgrade to 3-ohm Dynatek green coils.\\/

[maro]

solved

Solved, it was faulty plug caps. I had a spare set of inside caps (the longer ones). I replaced the faulty short one with a long one. I'm assuming, other than aesthetics, nothing will be harmed by this. Time to buy a new set all around, for back-up

[flyingace]

I hope it is electrical as pundits say. All you have to do is swap wire/cap #1 with wire/cap #4 and see if the problem shifts to cylinder #1. These wires fire from the same coil at the same time.

If it doesn't, you may have dreaded #4 carb syndrome. If the bike has been parked on the sidestand in the rain, water pools in the recess of the #4 idle mixture screw. Over time, this corrodes the spring and gunk gets in the idle and off-idle circuits. The symptoms can be intermittant, as in it idles OK once, then next time you stop, it's idling 25% slower due to #4 not firing. What happens if this continues too long is the plug gets loaded with carbon, fouls and then #4 won't fire at all.

A bunch of us ran into the same problem a couple years back, but that was with 850s with CV carbs. If you don't have CVs, ignore the above. If you do, you'll need to clean #4 carb idle circuit and replace the corroded spring if symptoms persist.

I will add that a new plug may temporarily solve the problem, but it's just a matter of time before the carbon fouls it too. Hopefully, you don't have #4 syndrome.