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M2 popping backfiring favouring front pot.
https://ukbeg.com/forum/viewtopic.php?f=8&t=18617		 Page 1 of 1
Author:  sloppy [ 13 Apr 2014 16:53 ]
Post subject:  M2 popping backfiring favouring front pot.
OK guys now I need more help....

Fitted a new exhaust the other day.
Previous owner has cut the elbow off a Vance and Hines pipewhich means I can bolt on anything. Bought off eBay with a removable baffle. Fitted it, OK but a bit quiet, took baffle out and I got dreadful running, backfires etc.
Back home and refitted old exhaust, still ran like a dog back fires and running on one cylinder, the front one.

Scratched head. Checked all pipe connection and tried again the next day. Ticks over runs lovely , no back fires hooray.

Turned it off, got me gear, testride....dreadful again running on one cylinder won't tick over didn't even leave the garage. :cry:

Definitely running on front cylinder and intermittent on the back one, seems to get worse the warmer it gets. I'm now thinking electrical, coil breaking down,duff leads or the like.

Bit fed up now. Any pointers gratefully accepted.......

:headbang:
Author:  FerrisBueller [ 13 Apr 2014 17:02 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
Sorry I can't help, but just adding another question to increase mine/everybody elses knowledge;

Do the ECUs on a Buell adjust themselves a bit when you add a different exhaust?
Author:  Dunno [ 13 Apr 2014 21:11 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
I had intermittent and then no firing on back pot on my M2... turned out to be the rear plug lead chafing where it goes through a P-clip by the choke/enrichener lever. Wasn't easily visible until the clip was removed.
Author:  pash [ 13 Apr 2014 21:22 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
:yt:

If the rear cylinder doesn't want to fire then you need to look for something specific to the rear.

The fuel system is shared
The air system is shared
The ignition system is shared up to the plug leads (it is wasted spark so can't be the coil)

So, that leaves:
Plug leads
Plugs
Dropped valve
Broken rings

But if you get good performance when it does run, mechanicals are unlikely to be the cause.
Author:  deepsix [ 13 Apr 2014 23:06 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
does an M2 use a engine temp sensor on rear pot?
Author:  sloppy [ 14 Apr 2014 07:35 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
Thanks for that.

Interesting about the chaffing lead.....I Think I am going to try some new leads anyway as the ones I have are the originals so 13 years old.

I did consider swapping the leads around on the coil to see if that improved the rear cyclinder but wasn't sure if this was a single fire or double fire coil. I guess if the front starts breaking down then it may point towards the coil.

Ill try later and see where we get to.

Frustratingly yesterday morning bike was running lovely at a standstill, ticking over and blipping no problem. I reckon it is something and nothing.

Cheers.
Author:  pash [ 14 Apr 2014 08:03 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
deepsix wrote:
does an M2 use a engine temp sensor on rear pot?

Later ones did, not sure if the ignition cuts the spark to front or rear or both but you could be onto something...
Author:  sloppy [ 14 Apr 2014 10:25 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
Interesting.

I have heard about the temperature senser and it does operate off the back one.

Anybody know where it is and what it looks like?? I imagine it is along the same lines as a water temp senser and sits in the oil flow somehow.

Cheers.
Author:  kevmean [ 14 Apr 2014 14:11 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
It just screws direct into the alloy of the cylinder head and picks up the heat from that, later bikes had it directly on the top with the single wire leading up out of the centre of the rocker cover earlier bikes had it to one side of the head.
And it does make the bike run like a bag of spanners if they start to play up, check first that it isn't just a bad connection at it's plug or the lead to it chafing and shorting out ;)
Author:  deepsix [ 14 Apr 2014 14:11 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
The sensor goes through the rear rocker box cover. You need a cut down the side socket to remove it.
This site has much useful info. It's for the X1 but a lot is common.

http://www.thex1files.com/
Author:  Maz [ 14 Apr 2014 18:53 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
Sloppy.....PM for you :)
Author:  jay irons [ 02 Jun 2014 20:00 ]
Post subject:  Re: M2 popping backfiring favouring front pot.
It was the rear cylinder temp sensor on mine. if you earth the wire to the sensor it will retard the timing on that cylinder to the point of it running like a single. Disconnected the sensor on mine and had no trouble since. The sensor was about 85 quid if I remember. mines a 2002 cyclone ;)
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