Ignition coil life?

[Likesbikes]

Hi guys. Generally how long do the ignition coils/leads last on these bikes?

Got a ‘99 that is having some issues, suspect it’s the pilot circuit on the no.3 carb but they’ve already been out and cleaned. Just investigating other things before the PITA of taking them out again (more specifically the PITA of putting them back in).

The coils didn’t seem to match the Haynes manual specs although I’m not particularly good with a multi-meter so that could be me, the bike runs fine once revving but misfires on the 3rd cylinder at idle.

Cheers in advance

[Gnasher]

That's almost a how longs is a piece of string question.  Some can fail in a matter of years others still working fine and everything in between.  As a general rule it's more mileage related than time.

As there's only two coils with 2 HT leads it would be 2 cylinders not firing, not just one, if you had a coil issue.

If you've had issues which prompted you to remove the carbs and clean he pilot circuit? Chances are it's still that, that's the issue.  Does the cylinder fire and run/rev above 4k?  If so it's not the HT circuit, it's the carb.

[Likesbikes]

Hey cheers from the reply.

Just back in from the garage for further exploration, on further examination my substandard ears seem to still hear a misfire at high revs and the feel of the exhaust flow at the tailpipe against my palm support this. Realise it’s not particularly scientific.

A spray of water on the downpipes reveals that #3 is running much cooler. Swapped the leads over between 2 and 3 and still running cool on 3  so I’ve eliminated that I think. Leads have been trimmed back and caps replaced in the last year or so. Checked gaps on all the spark plugs then swapped them around, still the same so I’m thinking the ignition is good.

The intake rubbers are nearly new, so I reckon it must be the carbs. They were out after we bought it for another issue and we had them cleaned while they were out. I do wonder if they only got a cursory clean at a local place.

[Likesbikes]

Oh forgot to say, it’s got just over 48k on the clock.

It’s not my bike, it’s the wife’s. We bought it cheap and there was a lot to tell me it’d never been looked after particularly well. Think it’s just a dog if I’m honest, trying to convince her to buy a Tracer lol

[BBROWN1664]

sounds like a blocked jet on #3

[Likesbikes]

sounds like a blocked jet on #3

Unfortunately it would seem so. As said I’m just trying to eliminate simpler things before resigning myself to that. Swapped the coils over and #3 cylinder is still missing/cold so it’s not that. The primary resistance is also a touch high on both, so they might be on their way out anyway. However it doesn’t seem to be the cause of this problem so they can stay for now.

As an aside I notice the replacement NGK caps are 5k rather than the specified 10k, what difference would that make?

[BBROWN1664]

if #2 and #3 are still working/failing whichever way round the leads from the coils are, the problem is fuel or air, not ignition. #2 and #3 both use the same coil and both fire at the same time.

So, its either the carb not supplying fuel or the valves not allowing air in/out of the cylinder. My money is on the carb

[Likesbikes]

That’s what I said, it’s not the ignition side as I’ve swapped the coils over completely from cylinders 1/4 and 2/3 and nothing has changed.

The coils resistance is a bit over spec but they’re working so they can have a reprieve. The question re the resistance of the caps (which also seem to work fine) is more out of curiosity.

Will be removing the carbs for a clean out next weekend, it’s not the first time with this bike but I’d rather have avoided that. This bike is the bane of my life and it’s not even mine haha

[unfazed]

Your plug caps will  give trouble long before the Coils ever will.Thankfully the caps can be dismantled and cleaned out. The biggest issue is the carbon resistors which can go faulty taking the resistance up to Meg Ohms which cause the caps to track on the outside and can be seen clearly at night.
I like the look of the original caps and usually buy a cheap set of NGK caps and break them open and use the resistor as it has a stainless outer wire wound resistor and will usually last as long s the coils.When dismantling the originals there is a tiny brass spacer which is usually corroded and breaks if you look at it the wrong way, but can be discarded when using the NGK resistor. The spring should fall out but may be corroded and stuck. Inside the cap there is a flat brass part which is part of the screw which needs to be cleaned usually scratched clean with a sharpened screwdriver.  Clean the spring and reassemble. Use Dielectric grease on the boots and all will be well for years.
On the carb front it is as you said most likely the pilot jets. I gave up trying to clean them and now replace them. The reason being that the internal of the pilot jet has a web type structure which is virtually impossible to clean properly.Replace the O-rings on the float valve and main jet with Viton/FKM or FFKM ones and it will save taking them apart  for a while again. Sizes are in the download section https://foc-u.co.uk/index.php?action=downloads;sa=view;down=93

[Likesbikes]

Hi again chaps and cheers for all the input.

Had the carbs out this evening and the bike is now mostly back together. Together enough to run anyway. Think I’ve got somewhere with the pilot jet and associated passages, the engine really picks up when blipping the throttle however the idle is rougher than ever now, although I also tinkered with the balancing screws while everything was out. The suspect number three was the only one where you couldn’t see a sliver of daylight through the butterfly and I couldn’t help myself 😖

Will get the vacuum gauges out tomorrow, bit late now to be annoying the neighbours. Will update when I get round to it

[Likesbikes]

After all that it’s the fuel level in the #3 float bowl, that’ll teach me for assuming!!

Can’t be bothered with it tonight, carbs out again in the morning. Any easy shortcuts to setting this up?

On the plus side, this morning we put a deposit on a very nice Fazer 8. This 600 might still end up in the river 😆

[unfazed]

After all that it’s the fuel level in the #3 float bowl, that’ll teach me for assuming!!

Why did you adjust the float levels?

[Likesbikes]

Why did you adjust the float levels?

I didn’t. But I didn’t check them either, just drained them

[unfazed]

Very unusual for float levels to be out on the 600, unless somebody before you tampered with them or replaced the float valves with spurious one. Did you use a clear pipe to check the levels? If so it can be easy to get it wrong. When you open the float drain to fill the pipe you may get an air bubbles and put the reading off. With a long pipe and it has filled lift it up tap it a few times and then drop it down below where you had it. This will normally dislodge any air bubbles.

[Likesbikes]

Cheers for the reply I’m on it. Just tweaked the little tang and refilled in the bench with the aid of spirit levels etc. I’ve already noticed the bubble issue you mentioned but we’re getting there, a mm or so within the mating surface now so a cuppa now while they’re draining. The only concern is if that bubble was there when it was tested on the bike I may still be chasing a non-problem 🤬

It was previously examined by a ‘professional’ due to time restrictions. Hoping this is it sorted because the bike needs to be gone soon