Low speed missfire

[berko_lad]

I was out for my first big blast on my 'new' Storm last night (a mix of A roads and motorways) and as expected, it was awesome.

I stopped a few times and it started easily and ran faultlessly every time and then.... I parked up and wandered around a classic car show near me and when I got back, she fired up as normal then when I pulled away, it suddenly dropped onto one cylinder. I revved it and after a short time, it cleared and performed perfectly on the way home albeit with the odd missfire. It also idled perfectly when I stopped at lights.

I parked up outside the house and then when I went to put it in the garage, the same thing happened. Low speed on one cylinder, revved to above 2k and from then on, ran as normal.

The only thing I did differently at the car show was to take off the seat and I did notice that the sidestand plate I keep under there had moved a bit further back to where the connectors for the magic boxes are so having seen some mention of this in other threads, assuming it's still doing the same thing I'll be looking at these over the weekend to make sure they're all ok.

But other than this and the normal plugs/leads is there anything else I should be looking at?

[lloydie]

Cleaning the carbs would be my first thing to do on the list .

[VTRDark]

Are you sure it's a misfire, firing on one cylinder cutting in and out or are you mistaking this for a bit of carb backfire and popping on the overrun. Or it could just be some dirt in the fuel system/carbs giving you a bit of stutter, going flat then shooting off.

Check you plugs, ht leads and make sure everything is good there and connected properly. If you find it firing on one cylinder do a coil swap and see if the opposite cylinder misses.

There's also a PDF workshop manual for download in the workshop knowlagebase section.

(:-})

[Wicky]

Could be normal carb fart - cured with less beanz...

[berko_lad]

It's definitely dropping onto one cylinder and normally, the carbs would have been high up on my list. It was just that it happened after it had performed perfectly for almost 100 miles of a variety of riding and had been started five or six times. Just seemed odd.

[Kev L]

Where are you based mate? Stick your location in your details so people know whether you are close by, they may be able to loan spare coils etc to eliminate potential problems.

[berko_lad]

Where are you based mate? Stick your location in your details so people know whether you are close by, they may be able to loan spare coils etc to eliminate potential problems.

I'm in Hemel Hempstead.

Will do!

[VTRDark]

OK check to see if both plugs are getting a spark by taking them out one at a time and rest the tip close to the frame, turn the bike over and see if they are sparking. Or just replace them with some nice NGK Iridiums as they are a serviceable item.

The next thing to check would be the HT leads make sure they are secured properly. You could swap them around see if the opposite cylinder starts to miss. If not do the same with the coils, also make sure all electrical connectors are clean and secure.

It also worth checking the front cylinder where the plug sits as you can get debris in there that may need cleaning out.

The problem is if it is intermittent it could be hard to track down, so by swapping items around and if you can tell which cylinder stops firing, you may be able to narrow down where the fault lies. Once you have swapped an item If the opposite cylinder starts to have the misfire then there lies the fault with whatever you swapped over.

It may also be worth checking the ecu's and plug connection in the tail under the seat as it easy for water/moisture to get in under there. Maybe disconnect them give them a quick squirt of WD40 or contact spray and re-connect. Just disconnecting and re connecting can work wonders sometimes.

(:-})

[Kev L]

If you still have issues after following Carls guidance I have spare coils etc to use for elimination purposes matey.
I am over in Hertford fella.

[berko_lad]

OK check to see if both plugs are getting a spark by taking them out one at a time and rest the tip close to the frame, turn the bike over and see if they are sparking. Or just replace them with some nice NGK Iridiums as they are a serviceable item.

The next thing to check would be the HT leads make sure they are secured properly. You could swap them around see if the opposite cylinder starts to miss. If not do the same with the coils, also make sure all electrical connectors are clean and secure.

It also worth checking the front cylinder where the plug sits as you can get debris in there that may need cleaning out.

The problem is if it is intermittent it could be hard to track down, so by swapping items around and if you can tell which cylinder stops firing, you may be able to narrow down where the fault lies. Once you have swapped an item If the opposite cylinder starts to have the misfire then there lies the fault with whatever you swapped over.

It may also be worth checking the ecu's and plug connection in the tail under the seat as it easy for water/moisture to get in under there. Maybe disconnect them give them a quick squirt of WD40 or contact spray and re-connect. Just disconnecting and re connecting can work wonders sometimes.

(:-})

Thanks for the advice, I'll be doing all of that over the weekend.

The tail thing is where I'll focus on first as that's where my sidestand plate was and even though it's plastic, it might well have knocked a plug loose.

[berko_lad]

If you still have issues after following Carls guidance I have spare coils etc to use for elimination purposes matey.
I am over in Hertford fella.

Thanks Kev. Appreciate that.

[VTRDark]

If I was in London I could have popped over and had a look, but unfortunately I'm still stuck in Guildford house and Pet sitting

Good luck with it over the weekend. I doubt you would have knocked a plug out as they are clipped in there pretty firm. But a bit of moisture is a possibility.

(:-})