Misfiring

Omar · 30-03-2021, 04:04 PM

Hi,
Just been out for a ride and the bike (1100 Evo) developed a sudden severe misfire. Like its running on one cylinder or suffering fuel starvation. I stopped the bike and had a quick look around with nothing untoward found. The bike then started and ran normally. With a lack of confidence I rode home OK.
I am thinking perhaps the fuel filter, but the bike has only done 3,000 miles. Any other ideas folks?

Ron1000 · 30-03-2021, 04:10 PM

Loose spark plug, loose HT lead, bad fuel or maybe it just had a tantrum.

Martin C · 30-03-2021, 04:53 PM

Start with the most obvious possibilities: blocked fuel-tank filler-cap vent; corroded or loose battery or ignition terminal; loose or dodgy spark-plug cap/lead. If there's no sign of a problem, change the spark plugs anyway, and see if the old ones both have the same colour deposits.

If the fuel filter was changed fairly recently, make sure the fuel hoses are securely attached to it, I've known one to come loose.

Intermittent problems can be a right bastard to locate the cause, so best of luck with this one!

Luddite · 30-03-2021, 05:30 PM

I doubt it would be the filter after only 3,000 miles, even if it is 8 years old. When I changed mine after 9 years and 10,000 miles, it showed little signs of use other than some discolouration.

http://www.ukmonster.co.uk/monster/s...ad.php?t=58075

If the bike's been standing over winter, perhaps the fuel's gone off a bit. Try a tank of fresh petrol if you haven't already done so.

You flashed your ECU recently if I remember correctly. If you've not done more than 200 miles since then, the ECU's autoadaptive parameters may not yet have relearned all the relevant values. Put a few more miles on and see if it happens again.

If it does recur, you may have disturbed something or pinched a hose when refitting the ECU so it might be worth lifting the tank and checking all electrical and fuel connections are secure, including the relays.

Omar · 30-03-2021, 08:25 PM

Thanks everybody for your suggestions. I have now done around 400 miles since winter storage and so the tank has had a few fills with ESSO's best stuff and the re-map should have settled down I hope. I will slowly go through the suggestions and hopefully find the fault before I get stranded. Now have 600 miles of riding the bike and really enjoying it.

Mr Gazza · 30-03-2021, 09:40 PM

It sounds like a loose connection to me, probably on or to do with the coils, but it could be lots of things.

My brother fitted electronic injection to his '72 Reliant Scimitar complete with learning ECU. Unfortunately he suffered a faulty sensor halfway through the ECU's learning curve and it tried to learn round it until the problem was spotted and sorted. The ECU had to start learning all over again.
Just mentioned that because it may have some relevance to you?

crawsue · 01-04-2021, 02:04 PM

If an Optimate cable has been recently attached it could be a loose battery connection, happened on a pals Multistrada....fitted by local dealer, went into “ limp home mode” similar to your single cylinder feeling....screwed up a good run into the bargain....��

Darren69 · 01-04-2021, 02:58 PM

Do they have coil sticks or normal coils? In either case it could be a coil failing, usually when they get hot. So coil sticks are more prone to this than the regular coil/ht lead type.

slob · 01-04-2021, 04:25 PM

They have 'normal' (very compact) coils

damien666 · 01-04-2021, 10:12 PM

Crank position sensor?

Darren69 · 02-04-2021, 06:35 AM

You would get an error code if the crank sensor failed or miscounted.

chris.p · 02-04-2021, 06:49 AM

I would suggest giving Neil a ring at Cornerspeed and see what he thinks it could be.

Omar · 02-04-2021, 10:09 AM

Thanks once again all for your suggestions. I have had a look under the tank and the only thing I have found is a relay / electrical connector that was swinging via a tie wrap. According to the manual it is for the fuel injectors? but it is actually in a different position to that shown in the manual's photograph. Hopefully a pic of it below?

I have made it more secure and will now put things back together and try again. Fingers crossed.

Darren69 · 02-04-2021, 10:18 AM

Dreaded DPO mods. Someone recently (Rob S maybe) suggested swapping over the 2 relays because if the other one is faulty the bike would then be dead.

fastnfat · 02-04-2021, 10:39 AM

I had something similar a few years ago, a misfire that didn’t clear though. Cheapest and quickest option for me was replace the plugs. Fortunately, for me, that cured it. Must have been one was breaking down which was a bit surprising as they had only done about 2k miles!

30-03-2021, 04:04 PM	#1
Omar Registered User Join Date: Jul 2019 Location: grimsby Bike: M1100evo Posts: 95	Misfiring Hi, Just been out for a ride and the bike (1100 Evo) developed a sudden severe misfire. Like its running on one cylinder or suffering fuel starvation. I stopped the bike and had a quick look around with nothing untoward found. The bike then started and ran normally. With a lack of confidence I rode home OK. I am thinking perhaps the fuel filter, but the bike has only done 3,000 miles. Any other ideas folks?

30-03-2021, 04:53 PM	#3
Martin C Bronze Member Join Date: Jun 2006 Location: Burton on Trent Bike: M900 Posts: 244	Start with the most obvious possibilities: blocked fuel-tank filler-cap vent; corroded or loose battery or ignition terminal; loose or dodgy spark-plug cap/lead. If there's no sign of a problem, change the spark plugs anyway, and see if the old ones both have the same colour deposits. If the fuel filter was changed fairly recently, make sure the fuel hoses are securely attached to it, I've known one to come loose. Intermittent problems can be a right bastard to locate the cause, so best of luck with this one! __________________ Owning a Monsta is not the beginning of the end, but it may well be the end of the beginning....

30-03-2021, 08:25 PM	#5
Omar Registered User Join Date: Jul 2019 Location: grimsby Bike: M1100evo Posts: 95	Thanks Thanks everybody for your suggestions. I have now done around 400 miles since winter storage and so the tank has had a few fills with ESSO's best stuff and the re-map should have settled down I hope. I will slowly go through the suggestions and hopefully find the fault before I get stranded. Now have 600 miles of riding the bike and really enjoying it.

30-03-2021, 09:40 PM	#6
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,815	It sounds like a loose connection to me, probably on or to do with the coils, but it could be lots of things. My brother fitted electronic injection to his '72 Reliant Scimitar complete with learning ECU. Unfortunately he suffered a faulty sensor halfway through the ECU's learning curve and it tried to learn round it until the problem was spotted and sorted. The ECU had to start learning all over again. Just mentioned that because it may have some relevance to you? __________________

01-04-2021, 02:58 PM	#8
Darren69 Transmaniacon MOC Join Date: Sep 2013 Location: Sutton In Ashfield Bike: Multiple Monsters Posts: 6,023	Do they have coil sticks or normal coils? In either case it could be a coil failing, usually when they get hot. So coil sticks are more prone to this than the regular coil/ht lead type. __________________ Roast Beef Monster! Termignoni and Bucci - Italian for pipe and slippers! S4 Fogarty, S4R 07T, 748, Series 1 Mirage

30-03-2021, 04:10 PM	#2
Ron1000 Registered User Join Date: Jun 2015 Location: Livingston Bike: M1100evo Posts: 863	Loose spark plug, loose HT lead, bad fuel or maybe it just had a tantrum.

30-03-2021, 05:30 PM	#4
Luddite Registered User Join Date: Aug 2011 Location: Southampton Bike: M1100evo Posts: 2,465	I doubt it would be the filter after only 3,000 miles, even if it is 8 years old. When I changed mine after 9 years and 10,000 miles, it showed little signs of use other than some discolouration. http://www.ukmonster.co.uk/monster/s...ad.php?t=58075 If the bike's been standing over winter, perhaps the fuel's gone off a bit. Try a tank of fresh petrol if you haven't already done so. You flashed your ECU recently if I remember correctly. If you've not done more than 200 miles since then, the ECU's autoadaptive parameters may not yet have relearned all the relevant values. Put a few more miles on and see if it happens again. If it does recur, you may have disturbed something or pinched a hose when refitting the ECU so it might be worth lifting the tank and checking all electrical and fuel connections are secure, including the relays.

01-04-2021, 02:04 PM	#7
crawsue Bronze Member Join Date: Nov 2016 Location: Glasgow Bike: M1100evo Posts: 258	If an Optimate cable has been recently attached it could be a loose battery connection, happened on a pals Multistrada....fitted by local dealer, went into “ limp home mode” similar to your single cylinder feeling....screwed up a good run into the bargain....��

01-04-2021, 04:25 PM	#9
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,712	They have 'normal' (very compact) coils

01-04-2021, 10:12 PM	#10
damien666 Registered User Join Date: Dec 2010 Location: Leeds, West-Yorks Bike: S4Rs Posts: 497	Crank position sensor?

02-04-2021, 06:35 AM	#11
Darren69 Transmaniacon MOC Join Date: Sep 2013 Location: Sutton In Ashfield Bike: Multiple Monsters Posts: 6,023	You would get an error code if the crank sensor failed or miscounted. __________________ Roast Beef Monster! Termignoni and Bucci - Italian for pipe and slippers! S4 Fogarty, S4R 07T, 748, Series 1 Mirage

02-04-2021, 06:49 AM	#12
chris.p Gold Member Join Date: Mar 2004 Location: lincoln Bike: No Bike Yet! Posts: 876	I would suggest giving Neil a ring at Cornerspeed and see what he thinks it could be.

02-04-2021, 10:09 AM	#13
Omar Registered User Join Date: Jul 2019 Location: grimsby Bike: M1100evo Posts: 95	Fault Thanks once again all for your suggestions. I have had a look under the tank and the only thing I have found is a relay / electrical connector that was swinging via a tie wrap. According to the manual it is for the fuel injectors? but it is actually in a different position to that shown in the manual's photograph. Hopefully a pic of it below? I have made it more secure and will now put things back together and try again. Fingers crossed.

02-04-2021, 10:18 AM	#14
Darren69 Transmaniacon MOC Join Date: Sep 2013 Location: Sutton In Ashfield Bike: Multiple Monsters Posts: 6,023	Dreaded DPO mods. Someone recently (Rob S maybe) suggested swapping over the 2 relays because if the other one is faulty the bike would then be dead. __________________ Roast Beef Monster! Termignoni and Bucci - Italian for pipe and slippers! S4 Fogarty, S4R 07T, 748, Series 1 Mirage

02-04-2021, 10:39 AM	#15
fastnfat Registered User Join Date: Aug 2014 Location: Birmingham Bike: M1100evo Posts: 124	I had something similar a few years ago, a misfire that didn’t clear though. Cheapest and quickest option for me was replace the plugs. Fortunately, for me, that cured it. Must have been one was breaking down which was a bit surprising as they had only done about 2k miles!