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Dodgy Starting and Rough Running |
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Posted: 23 Jul 2018 at 09:12 |
Morning all,
The old girl has developed a bit of an issue over the weekend and I was hoping someone may be able to shed some light or at least advise where to start looking. When firing her up this morning, I had the choke on and instead of the usual firing into life and running at high revs until I knock it down, she fired up and stuttered / ran rough at 2.5k-ish and then stalled when I went to giver her a blip of the throttle. Second attempt it was back to normal. Once on the road and up to temp, I went to open the throttle to get past the first bit of traffic and there was a pretty significant hesitation at 4k-ish followed by a slight rough running up the revs and felt down on power. Further down the road I got the opportunity to open her up properly (on the stop 3rd / 4th) and she was slow to get going again but felt someway towards normal once into her stride, up the rev range a bit. Nothing has changed with the bike since having the throttle bodies balanced at AP earlier in the year and she had been running better than ever after with the EVO airbox mod and Gabro chip. Having suffered with the swollen tank issue over the winter, I have been leaving the fuel cap up (as in, resting closed, not wide open) overnight and over the weekend, so I'm wondering if this could have caused any issues with evaporation etc. but surely tanks vent anyway!? So other than a fuel issue, I'm at a bit of a loss as to why the sudden change...she's running much leaner now than ever before, so it shouldn't be the plugs, water and oil levels are spot on, temp looks good while riding (75-77 degrees at a constant / decent speed (rising in traffic obviously)). Anyone experienced a similar sudden change in running and able to advise? I was thinking of just filling the tank and having a good ride around, hoping that might sort it but I didn't want to do more harm than good... Any advice / guidance much appreciated.
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Ice-mille
Moto GP Alien Joined: 19 Aug 2016 Location: Iceland Status: Offline Points: 786 |
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fill her up with fresh fuel, and take it from there
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Shake'n bake
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426hemi
Premium Member owner of the big bore! Joined: 30 Mar 2012 Location: cannock Status: Offline Points: 5676 |
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I serviced mine a while ago and used iridium plugs about 350 miles later I got a misfire about 4000 rpm, changed plugs to new standard plugs and been fine ever since.
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Thanks for the replies.
My plugs are the originals, hemi; Griff advised that they'd not need changing when it was in at AP for the TB balance etc. Pre Gabro chip and TB balance she was running quite rich, which is the only reason I mention that the plugs should be good, thinking that they'd now be less likely to get choked up!?
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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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Leaving petrol cap ajar would let moisture from air get in tank. Try syphonin a liter from bottom of tank into a clear container to see if there's any ethanol gunk. Do you use esso/bp super unleaded no ethanol in those.
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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The bugger's still doing it!!
I ran the tank right down the day I posted my original message, filled her up with 10L of the good stuff yesterday morning, have now done approx. 60mi and on the way into work this morning the hesitation seemed as bad, if not worse than the first time I noticed it. Seems to be worse with small / partial throttle openings at between 4-5.5k-ish but if I give her a handful, she takes off as usual once up the rev range a bit... Any further ideas??
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Ice-mille
Moto GP Alien Joined: 19 Aug 2016 Location: Iceland Status: Offline Points: 786 |
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Airleak, small vacuum hoses?
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Shake'n bake
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Thanks Ice, I'll get the tank up / off at the weekend and have a dig around...are there any main culprits to check that you know of?
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Quick update...got the tank and airbox off at the weekend and had a good poke around, checking plugs, leads, hoses and everything else but couldn't see anything immediately obvious.
Then, while I was lubing the throttle body mechanism and attacking dirty looking bits with a toothbrush and some WD40, I noticed that one of the wires / pins on the ECU side of the air pressure sensor had pulled out of the connector. For some reason it doesn't seem to want to go back in, so I've ordered a new one and hopefully that'll sort it. I also noticed that the valve nearest the oil breather is looking a bit tarnished / gummed up, so I'll get some sort of cleaner and a test tube cleaning brush and see if I can get that looking a bit better (for what good it'll do I don't know) and fingers crossed, she'll be as good as new! |
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Update #2.
Air pressure sensor plug replaced, everything else checked, cleaned and put back together and...still the same...!! Any ideas what to check next?? |
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Plugs & HT leads changed this morning and side stand switch bypass mod done just in case and still no improvement!!
What to try next...could??...fuel pump...??
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wigginsjp
Premium Member Joined: 11 Feb 2008 Location: calne Status: Offline Points: 3460 |
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take pump out and look at the tea bag filter in particular. They get a load of gel like old fuel on them and grit that in my case looked like sand. Give the a clean and try with fresh fuel.
Sorted out a running issue on a gen2 I tinkered with once upon a time.
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Aprilia RSVR Factory 2007 V2 1060cc Big Bore
Aprilia RSVR Factory 2004 Race Bike Kawasaki ZX10R 2007 Race Bike Aprilia Tuono V4 1100 Factory 2020 www.apriliaperformance.co.uk www.apworkshops.co.uk |
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wigginsjp
Premium Member Joined: 11 Feb 2008 Location: calne Status: Offline Points: 3460 |
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you checked the state of the brown connectors on the reg/rec for burning or melting also
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Aprilia RSVR Factory 2007 V2 1060cc Big Bore
Aprilia RSVR Factory 2004 Race Bike Kawasaki ZX10R 2007 Race Bike Aprilia Tuono V4 1100 Factory 2020 www.apriliaperformance.co.uk www.apworkshops.co.uk |
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Thanks for the replies / suggestions.
Next step is to get the tank off again and check th pump assembly etc. so I’ll remember to have a look at that strain / filter. The brown connector is gone already and everything else wiring-wise looks good...
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David451
Moto2 racer Joined: 04 Jul 2018 Location: Lanark/rigside Status: Offline Points: 165 |
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try running it in the dark and look for tracking at the coils you might hear it as well it could be the Eprom that's died as well you keep your old one
It's a hard one to find if you don't have diagnostics
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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What am I like looking for at the coils if I run it in the dark?
If it was a coil issue, would that show in the plug condition on the corresponding lead? I’ve got a recent Gabro EPROM chip in it but I could swap the old one back in to test...
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David451
Moto2 racer Joined: 04 Jul 2018 Location: Lanark/rigside Status: Offline Points: 165 |
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looking for the current running down the component to earth you can see and sometimes hear it blipping the throttle to load it. If it’s a particular cylinder then yes it should show up on the plug
You have the eco kit fitted so look down the throttle bodies make sure the screws are tight on the butterfly’s also watch as it’s running ref fuelling one side to other and that they are both in sync in case some linkage has come adrift
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David451
Moto2 racer Joined: 04 Jul 2018 Location: Lanark/rigside Status: Offline Points: 165 |
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that’s evo fokin predict and yes swap chip back
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David451
Moto2 racer Joined: 04 Jul 2018 Location: Lanark/rigside Status: Offline Points: 165 |
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I note you mention tank issues previously just make sure the tank is venting mine has two one for the tank that vents through the cap and the other for water or spillage in the neck but if it was blocked you would get a big wish as you open the cap
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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Thanks for the pointers David, all added to the list of checks for this week’s evenings in the garage!!
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