Hesitation, surging and crap mpg.

[gryphongryphon]

Yes that would have been my next move if changing coil hadnt have worked,CDI , some on Ebay for about £25 when I looked, good luck with it, I assume you have changed plug leads and caps already.
Edit . There seems to be lots of bits for sale in the forsale /wanted section.


Edit 2 drained carbs as well first thing I did didnt help me , but may help in other cases.

[Lawrence]

Just tested for a good spark on all cylinders.  Pulled each HT lead off in turn, stuck a spare plug in it and held against the head.  Got a white/blue spark but not a 'fat blue' spark as they describe in Haynes.  Oddly though, it started up exactly the same with only three plugs connected (any three) as it does with four.  Took the reg/rec off and checked with a meter, all appeared to be ok; lowest 660, highest 685 with the others spread out between.  Also tried it with the reg/rec disconnected and it still misses occasionally at 4k in neutral so it's not that.

What next?  Anyone got a spare CDI I can borrow to test?

[Torque]

[size=78%]What next?  Anyone got a spare CDI I can borrow to test?[/size]

I've bought one and seller does not want returns, so if you are still interested PM me.
Unfortunately for me it works the same as my old ECU.

Just sorted my Fazer from stuttering and hesitation , it was a coil, I detected it by pull off plug leads at idle 1 at a time, 2 and 3 when removed one at once the hardly caused a deterioration in idling.When I pulled off 1 or 4 plug cap, engine at idle speed nearly stalled. So changed coil to plugs 2 and 3 , problem solved ,genuinely runs better than ever because it has had a slight stutter from low revs ever since I have owned it.

Did you measure that bad coil? I am curious if ohms are correct. I've got similar issue I think, I measured the coils (and they are fine), but I am curious if they can be broken even if resistance does not show it.


EDIT

I've changed coils already, I thought they might've been ok at low revs and unable to provide enough juice to spark at high revs but it made no difference :/  I'm going to get the reg/rec and cdi off today and see if I can get them tested at my local dealer.

Maybe we can temporarily exchange ECU for coils?
I did not replace mine yet, but I did not want to buy a spare since ohms are correct.

[Lawrence]

I've just tried a cdi and it's made no difference :/ I've changed:

Carbs
Coils
Plugs
Plug caps
Cdi
Reg/rec unplugged (which should rule out the generator too I think)
Tps
Removed air filter

Rubber intake pipes/joins all seem to be ok but that would cause too much air/not enough fuel anyway.

What else can it be?

[Fazerider]

Defective wiring or poor connections in the ignition circuit? Pick-up coil?

[Lawrence]

Defective wiring or poor connections in the ignition circuit? Pick-up coil?

I've checked wiring (what I can get to, at least) and there was nothing un-toward.  Where's the pick up coil and how can that be tested?

Ta

[Fazerider]

It's inside the generator cover detecting the lump on the edge of the flywheel. The pickup coil is pretty much integral with the generator because the wires exiting the cover are all bonded together in a rubber seal. Since the generator/pickup is a bit fragile when removed from the cover, getting hold of the whole assembly is probably the best solution.
A resistance test is unlikely to show a problem. You know it's working most of the time already, an intermittent short between two turns isn't easy to spot without specialist equipment. If there's an obliging foccer near you, swapping generators would be the easiest way to check.

[Lawrence]

Thanks for that, I'll see what I can do

[Torque]

@Lawrence
Hi mate, any update on your FZS?

[Lawrence]

Not yet, I've not really had time to look at it lately.  I'm going to check cam timing at some point too.