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+--- Thread: fzs missfire (/showthread.php?tid=64731)
fzs missfire - xrigger - 27-07-13
Hi all,
Four months ago my '98 fazer died on me on the by pass doin about 80.
Fiddled with the choke an dropped down to 3rd and it picked up again but wasn't running quite right. managed to limp home 4 miles, by which time it it was back to normal.
No probs since then apart from tickover so, 3 weeks ago, took off the tank and drained off quite a bit of water. Cleaned thoroughly an flushed carbs out till they ran clear. Have had no trouble till today, when the same thing happened on the same by pass!
Got home again with the help of the choke and low and behold its now running 'normal' again.
However there is a bit of a missfire when revving steadily up to 7-8000 rpm and tickover is a little erratic, the rev counter fluctuating 9-1000 rpm.
Seems like a fuel issue but would be glad of any advice.
Re: fzs missfire - darrsi - 27-07-13
Do a quick TPS check to eliminate it.
Re: fzs missfire - xrigger - 28-07-13
Sorry Darrsi, what's TPS ??
Re: fzs missfire - xrigger - 28-07-13
Just realised, TPS would be on injection engine, mines '98 carb. Apologies for the confusion.
Re: fzs missfire - elbrownos - 28-07-13
The FZS600 does have a TPS.
Follow steps 2-6 of http://foc-u.co.uk/index.php/topic,91.0.html
Re: fzs missfire - darrsi - 28-07-13
Hope i'm not too late, but a word of warning if the needle goes to 10,000rpm do not turn the key to the off position.
If it goes to 10k then turn the ignition on so that the needle goes back to normal, otherwise the needle drops to the right then you'll have to take the clocks apart to spin it anti-clockwise back to the correct position.
Obviously if you have the correct T25 torx tool at the ready then it's okay to attempt to adjust the TPS if needs be.
I had a faulty TPS recently and my bike felt jerky, and also the RPM needle was all over the place, that's why i'm suggesting eliminate it first, because it's a very quick test.
Re: fzs missfire - xrigger - 28-07-13
Thanks for the correction. Havn't done anything yet. Could you explain what I would be doing by setting the tacho at 10000 rpm and exactly how I eliminate the TPS from the list of possible problems
Re: fzs missfire - darrsi - 28-07-13
Basically you just want to test firstly that it's okay, and also if it's in the correct position.
Turn ignition key on (no need to start the engine)
Unplug the TPS, which is the black thing on the right side of your carbs. I normally use a key to help with the catch.
The rev counter will then display a code to say that it's either unplugged or not working. It will go from 0rpm to 3000rpm (3000rpm is a faulty code)
Then simply plug it back in and see what code it gives next.
5000rpm is good, and where you want it to be.
0rpm or 10,000rpm means it needs adjusting, which involves undoing the 2 screws with a T25 tamper proof torx driver, and literally twisting the TPS sideways until you see the needle land in the 5000rpm position.
4000rpm means a dodgy speed sensor, but i doubt very much this will apply to you.
And if it goes to 3000rpm then your TPS is likely to be knackered.
As i said earlier my bike definitely misbehaved before i changed my TPS so it's worth a quick check.
Also the erratic tickover and fluctuating RPM needle could be symptoms of a dodgy TPS.
If you need to adjust the TPS then the bike must be at operating temperature, and the tickover speed should be around the 1200-1300rpm mark.
And don't forget, if it hits 10,000rpm turn the engine on until you are ready to adjust it to put the needle back towards the left side, otherwise it's front fairing shield off, then remove clocks and take it all apart to move the needle back. It's not difficult or anything, it's just time consuming and avoidable.
WORTH A QUICK READ: http://wiki.seloc.org/a/Throttle_Position_Sensor
Re: fzs missfire - xrigger - 28-07-13
Cheers Darrsi, if I don't cure the probs I will post again
Re: fzs missfire - darrsi - 29-07-13
(28-07-13, 07:55 PM)xrigger link Wrote: Cheers Darrsi, if I don't cure the probs I will post again
I'm not saying this is your problem, but it's certainly a possible cause, and also the quickest and easiest place to start.
Re: fzs missfire - xrigger - 29-07-13
TPS ok, went to 5000rpm. Just been out on the bike and it seems ok apart from erratic tickover and I think a slight loss of power. Going to get the carbs balanced next week but in the meantime, any ideas as to why it would suddenly cut out the way I described ?
Re: fzs missfire - darrsi - 29-07-13
If you're using the choke then it sounds like not enough fuel.
Maybe your carbs are well out of sync and just need levelling.
When i was balancing my carbs this morning if i turned the screw the wrong way the bike sounded like a tractor!
Re: fzs missfire - darrsi - 29-07-13
Make sure you have no kinked fuel pipe at all, and also make sure your fuel tap is fully switched on.
Re: fzs missfire - xrigger - 29-07-13
Thanks Darrsi
Re: fzs missfire - Thorn - 29-07-13
If it was raining in both cases the bike died on you, it might be plug caps, I've had the exact same experience lately. Easy to check, pull the plug caps off, and check if they're damp, shaking the caps around a bit will certainly get the water out.
Re: fzs missfire - unfazed - 30-07-13
Faulty TPS or out of synch carbs will not cause it to die like you describe. Most likely electrical issues, If it was raining it is almost certainlly electrical and the most like culprit is arcing or loose plug caps. Remove the caps from the coil wires and cut about 10mm off the wires. Spray abot 30mm of the ends of the leads with WD40 and screw the caps back on. This should prevent moisture getting in again. Hopefully it will solve the issue.
Re: fzs missfire - Fazerider - 30-07-13
Unfazed's suggestion is a good idea anyway and his point about TPS and carb sync is valid, but it doesn't sound to me as though the cause is electrical if using the choke improves matters.
If you'd found a lot of water in the tank then there is probably rust present. The filters in the tank and after the fuel tap should prevent debris reaching the carbs, but water can still cause corrosion in the carbs themselves. I think it would be worth taking them off, cleaning them out and blowing the jets clear.
Re: fzs missfire - darrsi - 30-07-13
He said water in the tank, but no mention of it raining on both occasions when it died??
When i said not enough fuel earlier, what about the opposite, too much air, as in an air leak?
It would explain an erratic tickover, and also using the choke would obviously cut down on air intake.
Maybe cracked or loose inlet rubbers?
I'd be inclined to get a new inline fuel filter as well, for the sake of a few quid, it could be slightly clogged with rust particles.
Re: fzs missfire - xrigger - 04-08-13
Ta for the input everyone, am slowly working my way around the possible faults mentioned. Will tackle the carbs if all else fails !