Misfiring on takeoff in first and second gear

[Exitaph]

I've got 77 xs650 and it recently started acting sluggish and misfiring randomly. It only occurs during takeoff in first and second gear. After I get to third and up it's fine. I'm still new to this and don't really have a clue where to start. I've done some searching but couldn't manage to find someone with the same problem.

Any ideas?

 

[weekendrider]

Does it happen at lower rpm only in first and second? Say above 3K rpm it runs well but getting there is a struggle?

 

[Exitaph]

That sounds about right. I'm not sure of the exact rpm but it sound like it's happening around 1500-2500. I took it out today with my gopro to show what it sounds like.

 

[weekendrider]

You don't wind them up much. You are shifting at 3,500 - 4K tops?
6 -7K doesn't hurt them, promise.
I would revisit the pilot circuit, it doesn't take much fuzz/ grit/ grime to interfere with fuel delivery

 

[Exitaph]

So you're saying I should be shifting around 6-7k? My bike revs crazy loud after 3k. Feels like I'm over working it.
If it wasn't getting enough fuel wouldn't it also misfire/sputter while in neutral?

 

[5twins]

No, not always, but you can occasionally wind it up high like that without hurting anything. Idle doesn't need quite as much fuel as trying to rev it to 2500. I have to agree with WER, start by cleaning your pilot circuit. Also, your idle speed in that video sounds high. It should be 1100 to 1200. If you can't set it that low without the bike stalling, that's another indication that your pilot circuit is clogged.

 

[Exitaph]

I just cleaned out the pilot jet and blasted the circuits with an air compressor. Still misfires in the same way. I have pod air filters and I went up to a 27 pilot jet. Maybe that too low still? But it only started doing this recently.

 

[weekendrider]

Did you spray carb cleaner through the body
passages and check flow out the holes in the throttle body just behind the throttle plate? Also through the pilot jet hole in the float bowl checking flow from the main jet chamber? Your video seems to have the stumble after the throttle plate is opening but before the needle is fully lifted. What I hear isn't a misfire but lack of fuel stumble. Maybe others will chime in and we will both get schooled.

 

[TwoManyXS1Bs]

It reminds me of skipfire, ignition interruption. Possibly caused by vibration.

Could check the condition of your kill switch.

Check the integrity of the ignition connections under the tank.

Maybe condensers, check for points arcing...

 

[Armin]

I'm with 2M ... to me it sounds like an wiring issue and beside the topics he mentioned I would also check the condition of the battery and charging system as well as the wiring in and around the headlight bucket.

Furtheron, if your bike is stock beside the pod filters or you didn't change anything recently, I would go back to the previous/original jetting. Especially because you said it started recently ... sounds to me like it worked before.

One more thought to the pod filters..... If the problems starts with the installation of the filters I would also check if they really fit on the carburetor, some of them partly covers the air intake of the idle/enrichment circuit