Fazer 600 - Cylinder #1 Issue

[NJD]

Hi,

So will be phoning local shop tomorrow, but posting for ideas / more places to look.

My MK1 Fazer 600 has developed a running fault that has worsened over the past few rides. May be related to the damp weather as was fine before temperatures dropped below 5, but seems to be struggling since.

Started out as small lumpiness under throttle at random then progressed onto sounding like it wanted to stall at idle with the clutch pulled in if sat at lights for an average perid of time, and sounded funny after a ride (on one occasion) in neutral and is now causing the bike to bog down / struggle to pull away below 3,000 rpm or from a dead standstill. Bike requires a lot more throttle to pull away even close to smoothly and often jerks in the process like its going to cut out but doesn't and then gets going.

Exhaust #1 (sitting on bike, far left side) is the problem as its not as warm as the others after a ride (tested by spraying water on downpipes). Its getting warm, but not as warm as it should.

Bike runs fine above 3,000 rpm and starts fine first time on the button without issue. Gears changing fine. Clutch adjusted as it should be.

Spark plugs are fairly new, caps are original. Cap #1 fitted tight and golden part inside looks shiny (not rusted).

IMO based on the fact I've only had it a few months and was serviced by the shop before that (including going back to have the fuel sender replaced) its either something intermittent (coil, but not a complete failure since the one beside #1 is warm and runs fine?) or a slowing failure.

Any ideas?
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[Bhud]

Remove the spark plug and have a look

[Kawasaki Jimbo]

It does sound like an ignition coil failure. Correct functioning at speed sounds counter-intuitive because you'd expect demand to be greater, but I've had a similar problem with the car. A coil swap would be more conclusive than a multimeter check IMO.

The two coils probably supply 1 & 4 and 2 & 3. I guess #1 could fail intermittently while the same coil might still be working for #4? (I don't know that for a fact though. Interested in other people's thoughts.)

Although the symptoms don't totally fit I wouldn't discount carb-icing. Silkolene Pro-FST in the tank, and check the carb heater pipes if Fazer's have them.

[NJD]

Photo of plug from problem cylinder.

I realise there are charts to compare to, but if someone could spell it out in layman's terms:

https://i.postimg.cc/Vk4yhbZh/20201206-144645-1702.jpg

edit:

There is a mark on the ceramic part, but I've never pulled them in the months I've owned it so cannot be sure if it was there before the problem / and if this is an indicator of a problem from the HT lead / damage?

https://i.postimg.cc/K8Gwt8cD/20201206-144842.jpg
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[F18]

Usually wasted spark ignition would affect both to some degree or other, time to test its 'other half' (#4 ?).

/edit:

Cross-posts, I hadn't seen your photos.

If that has been tracking, a good fault. Clean it up fully and if clear ceramic below then clean the inside of the cap and re-try it.
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Summer is just around the corner

[weasley]

Had the same on my Thundercat, it turned out to be a failed plug cap, diagnosed only by testing the resistancec(should be 10kΩ from memory). Cap just unscrews from the HT lead.
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[Nobby the Bastard]

I would assume a knackered carb rubber for stalling at the traffic lights.

I wouldn't consider an ignition fault because you typically lose two cylinders on a modern four because wasted spark, but.... If a plug or lead is breaking down it is possible for the spark to jump from the breaking down lead and the other cylinder to still work perfectly.

Start it up when it's dark and see if you have a spark jumping somewhere between the coil and the plug.
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Sprint ST 1050

[Arfa__]

Had same symptoms on my FZS600 few years ago, turned out to be a crack in the spark plug cap.

Was hassle to replace HT leads in coils, so just trimmed original leads slightly then shoved them into some new NGK caps. Job done.
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Yamaha FZ6 S2 2007

[NJD]

[oilyrag]

They are prone to arcing from the spark plug caps. You could unscrew the caps from cylinder 1 and 2 and swap them and see if the problem moves to cylinder 2. You could do the same with the spark plugs. Do one thing at a time.

[NJD]

[andys675]

chop 1cm off the end of the ht lead in case there's no copper core in the end of it, screwing the cap in actually damages the core over the years so trimming it back will give a better connection.
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[Nobby the Bastard]

[A100man]

Treat the old girl to a new set of plugs while your in there.. Cost is only a few quid.
carb rubber looks quite bad. standard trick of wrapping with self-amalgaming tape will eliminate that possibility.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[oilyrag]

[NJD]

[Tdibs]

Yep my money is on tiny hairline split in plug cap. As other have said, trim 1cm off HT end, screw into new cap. You have already identified the problem cylinder.

And yes, those boots wont last forever. Dog of a job, good luck
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Previous : 09 Vanvan 125| 02' Sv650s || Current: 1999 Xj600n | 1992 DR650 RSE | 2005 Fazer 1000

[oilyrag]

[NJD]

Bingo.

Replaced the O.E.M cap with a brand new NGK SD05F cap and the exhaust got hot, as it should, straight away. Only realised how much power I'd lost when I attempted to pull away to test ride after fitting.

For what its worth the O.E.M cap looks to be in perfect condition and is crack free all over, and the gold bit that the HT lead screws into is shiny and free from debris or marks (bright gold). So it may be internal, or it may be that the HT lead was slightly mangled due to age / not forming a good connection. In either case I'm glad its a cheap fix, as I'd hoped, as the bike now continues to run like a dream in weather worse than what other bikes have left me at the side of the road.

Used the same spark plug so was definitely the cap or the HT lead needing cutting.

Will replace other three when I can go back and pick them up because why not. Assume their the ones that the bike rolled out the factory with so can't hurt.

Regards those cracked boots I've realised -- if it makes a difference -- that they're the "carb intake stubs" not the ones that go from carbs to airbox (rubbers). Still will need replacing at some point, but neither part looks to be particularly expensive via eBay second hand for average - good condition ones. A job for the future, but not yet.

Many thanks for all the advice.
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[oilyrag]

If there's no change in rpm when you spray carb cleaner around them don't change them. It won't make any difference to how the bike runs.

[weasley]

[oilyrag]

They don't fail. They just crack on the surface. The cracks don't go through. The next time you see a square headlight Fazer 600 parked have a look at the intake manifolds. I can pretty much guarantee they will be all be cracked on the surface. The main reason they get replaced is people don't like looking at the cracks or they think replacing them will fix a running problem but it usually doesn't because the cracks don't go all the way through. If you want to replace them you can get genuine replacements from Yamaha but they are mad expensive. You can get good quality after market Tourmax ones for around £100 or you can get cheap ebay ones for £20.

[NJD]

I've seen the el-cheapo twenty-pound ones on eBay, but have since purchased a job lot that had some genuine ones in from a bike that had been stripped for twenty quid. I can see one has a crack, and the other three look to be in good condition. For the price I can't complain at whatever turns up.

Wont be something I do anytime soon as the bikes running mint in this cold climate without fuss, and also is a lot of stripping parts just to replace something that -- for me at least -- is only a visual issue at the moment; but is worth chucking in a spares box.

You could probably build the bike for a tenner based on the mass cheap parts available via eBay.
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[NJD]

[BUMP - Fazer 600 1999 MK1].

To recap: in December 2020 I had a running issue that turned out to be a coil related issue and appeared on #1 cylinder. I solved this issue by fitting new NGK spark plug caps to all four HT leads and trimming the original HT lead a little to give it a fresh lease of life.

Today, three months on, the poor running appeared again but this time was on #2 and #3 which is on a separate coil to last time. Both exhausts were running noticeably cooler than #1 and #4.

I fitted four new spark plugs, but that made little difference. I trimmed back the HT lead on the problem cylinders and they came back into life. They were tight to the cap before I trimmed them, but trimming them worked for whatever reason.

I went for a ride after trimming the HT leads on the problem cylinder (#2 and #3) and it ran as good as I'd expect it to. The exhausts were hot and spraying water on them caused the same amount of smoke as #1 and #4. So, for now, all four exhausts are at the same temp and it works (omitting that it will be one or two rides before I'll be convinced its fine and working as it should without issue).

I can't do anything but play the waiting game for now, but would replacing the coils be your next investment? I'm baffled by (a) why the other coil failed to last time, and (b) why trimming the lead fixed the issue when they were trimmed three months ago and have worked okay since.

I did also charge the battery today (removed it as I didn't want spilt fuel from removing tank hose to get on it) and it read 90% when the charger first started charging it. I can't be 100% sure that translates into anything as you can charge the battery and plug it in again straight after and it doesn't read 100% (Sealey branded charger).

Anything that may cause the coils to play up that trimming the HT leads solves?

Bit of an odd one to be honest.
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[Robby]

My best guess is that the whole ignition system is a bit borderline, and a bit of corrosion in those HT leads was the straw the broke the camel's back.

Personally I would be going through the system to eliminate any corrosion first - CDI connector, any wire going into the coils and where they earth onto the frame, and new HT leads and plug caps. In fact if it was me I would likely fit new coils as well, unless they cost silly money.