Is this a misfire?

[dextersaurus]

https://www.youtube.com/watch?v=O_b-yVmN7WU

Got it running today and took it for a run, started this about 4 miles in. It's been sitting for a month without any wiring loom in it so maybe it's just needing the plugs cleaned up but i'm not sure.

Cheers

Dunc

[0l0dom0l0]

Hmm. Best bet is to do the downpipe trick tbh. Even when the bike is hot, leave it for 10 mins parked up and the pipes will be cold by then, but you've still got the coolant temp.

Spray the WD40 on all to check.

Its a difficult one because I thought it would be more obvious if it was running on 2.
____________________
CBT Passed: 30/08/2009, Theory Passed: 31/08/2010, Mod 1 Passed: 6/9/2010, Mod 2 Passed: 13/09/2010. Restriction ended 13/09/2012.

Bikes: 2007 Derbi GPR 50, 1998 Yamaha Fazer 600 (written off), 2002 Yamaha Fazer 600, 1994 CBR 600F, 2003 Triumph Daytona 600, Kawasaki ZX6R J1.....Current: 2006 Yamaha FZ6, 1998 Suzuki TL1000R and a Honda VFR 400 NC30.

[kal9001]

Sounds abit like my car did when it wasnt firing on two and three. The car was a problem with the coil pack, It has somehow come loose a little bit in the cold and just needed pressing back into place, Not sure how relevent this is for a bike though.
At the risk of sounding patronising all I could suggest is try the obvious thing of making sure everything is plugged in firmly where it should be and that there arent any loose or missing connections.
As the wiring loom has recently been worked on this seems the most likely culprit but it could just be coincidence and the issue may not be wiring at all.
____________________
Anyone stupid enough to think we will drag a load of wooden horses full of soldiers into our city is certanley stupid enough to drag all of ours into theirs!

[dextersaurus]

Just did a wee bit more investigating, and the bike runs perfectly when cold. it's only when it heats up that it starts misfiring.

It'll start fine, auto choke comes on, sits at 2.5k for a while, then drops down to 1.5k when the coolant reaches 50 degrees. can ride it for a while and the throttle response is spot-on, but when it gets to 75 degrees, it starts acting up.

No idea what the cause of that could be other than dodgy spark plugs.

Dunc

[SirEdward]

Can you restart the engine once it's at operating temp? (70*C+)
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"Beyond a critical point within a finite space, freedom diminishes as numbers increase. This is as true of humans as it is of gas molecules in a sealed flask. The human question is not how many can possibly survive within the system, but what kind of existence is possible for those who so survive.

Pardot Kynes in "Appendix I: The Ecology of Dune""

[dextersaurus]

Yes, but it struggles a bit and idles at below 1k. takes one or two tries before it will stay idling.

Dunc

[0l0dom0l0]

Could be your 02 sensor in the exhaust is broken. Is it connected?

Reason I ask is because these aren't active when the bike is cold. It runs of a different program until its up to full operating temp and would display symptoms exactly like this if its giving an incorrect afr reading.

You could try chris reds trick and buy yourself a lead off amazon and use easy tune software. It will show you any fault codes in the ecu and might help sort it out.

Also, go back to basics. Check all 4 cylinders have a spark when its warm. If they do its got to be fuel related which would make me think the sesnor is playing up.
Hope that makes sense!!
____________________
CBT Passed: 30/08/2009, Theory Passed: 31/08/2010, Mod 1 Passed: 6/9/2010, Mod 2 Passed: 13/09/2010. Restriction ended 13/09/2012.

Bikes: 2007 Derbi GPR 50, 1998 Yamaha Fazer 600 (written off), 2002 Yamaha Fazer 600, 1994 CBR 600F, 2003 Triumph Daytona 600, Kawasaki ZX6R J1.....Current: 2006 Yamaha FZ6, 1998 Suzuki TL1000R and a Honda VFR 400 NC30.

[dextersaurus]

please see this thread, proper one. https://www.bikechatforums.com/viewtopic.php?p=2886932#2886932

Dunc