Author Topic: Mysterious misfire (Read 5548 times)

taksi · « **on:** 17 December 2011, 11:57:36 am »

I ride a '58 plate FZ1 Fazer and have had it for around 18 months during which it has beeen faultless. Last Tuesday, however, I went into town and found it had developed a weird misfire. When moving from a standing start or when filtering on a closed throttle, then opening up there was a severe miss as the engine virtually stopped then picked up, then stopped and picked up again before flying off up the road. Disconcerting! If the revs are anything over closed throttle (ie 1800rpm) there is no problem. Had the fairings and tank off to see if a connector was making/breaking, especially the throttle position sensor, vac pipe adrift etc but couldn't see anything so opened them up sprayed with WD and reconnected all the ones I could see (except ECU) and went for a ride. Got to the end of the street, still the same. BTW plugs changed about 2k ago. Any ideas gratefully received before it goes to Mr Yamaha and my wallet takes a beating. No fault codes on the dash either. Baffled!

Ta very much in anticipation.

Taksi

Taksi

oldmotherfoccer · « **Reply #1 on:** 17 December 2011, 12:11:04 pm »

bit of dodgy fuel perhaps, have you let it run down lower than normal before filling right up ?? might be a bit of dirt somewhere, take her for a nice blat and then around town and see if she has calmed down a bit

taksi · « **Reply #2 on:** 17 December 2011, 12:47:58 pm »

Thanks for the reply. Use the bike for daily commute so gets new tankful of fuel every 4-5 days. Last thing I did was put the bike away after washing the commute crud off it last Friday and then put her in the garage over the weekend. Next time out of the garage was the Tuesday, that's what led me to think maybe I'd got water in the electrics but can't see anything wrong. Sprayed connections with ACF 50 as well. Hey Ho.

taksi

Falcon 269 · « **Reply #3 on:** 17 December 2011, 01:37:49 pm »

Misfires seem to come up often in discussion on the FZ1OA forum.

http://www.yamahafz1oa.com/forum/forumdisplay.php?f=10

Coil failures seem quite common.

taksi · « **Reply #4 on:** 27 February 2012, 09:45:39 am »

Many thanks Falcon. Looked at the link and then bought 4 coils from e-bay for £100 quid. Sorted. Multimeter readings all ok but I suppose they're not under load conditions then. Process of elimination nailed down no2 coil so now I have three spares. Still, I'll recognise the symptoms straight away next time and any new knowledge is always a bonus. Still disappointed it has failed at 12,340 miles though, thought they'd last longer than that. Looking through that link it seems to be a regular occurance and something maybe Yamaha should be looking at.
Thanks once again, buddy

Taksi

Falcon 269 · « **Reply #5 on:** 27 February 2012, 05:07:44 pm »

That's a relief, eh? I agree that coil failures at this sort of mileage isn't acceptable. At least you've got replacements ready for the next time, though.