misfire

what is misfiring and how do you know when a bike is misfiring? is it just when a plug(s) is not sparking or is there more to it? is there a way in daily use, w/o removing the plugs and checking?

not sure if i'm checking the plugs correctly anyway. i remove but keep hooked to the wire, and lay on the cylinder and turn engine over. that the way to check? i don't see much if any spark in any, and spark isn't blue - i tried all a few weeks ago. bike starts and runs though. i'm sure i'm doing something wrong ...

 

Not enough info , when do it , what rpm ect ect missfire?, but to remove a plug and earth it and not in bright sunlight or well lit room you should see a spark when turn over motor , ranging from a yellow to a blue coloured one , a engine will still generally run/start on a yellow spark , blue the better.....

 

What is misfiring?

Not a textbook definition, but it's when the fuel charge doesn't detonate for one reason or another. It can be because of bad/no spark, bad timing of the spark, lack of compression, and/or improper air/fuel mix (someone correct me if I missed some, it's early). Oh, I suppose predetonation might also count as misfiring.

How do you know when a bike is misfiring?

You can sometimes hear/feel it as an irregularity in the even tone/vibrations. Sometimes you can feel a change in power when a cylinider either drops out or comes back online. Though if you're not really familiar with a specific engine, you might not realize what you're hearing or feeling is abnormal. When I had 2 cylinders misfiring, I realized it but noticing those two heads/exhaust headers weren't gettign hot. Looking at the spark coming from the plugs won't necessarily show you a misfire (unless you can count really REALLY fast), but checking the condition of the plugs might indicate something. Like if one is fuel fouled, you can guess it's not all getting burned due to regular misfires.

that the way to check?

Yeah, as HooNz mentioned, that's how you check for a spark (make sure there is no fuel fume buildup in the area when testing like this). Depending on ambient lighting, it might be hard to see the spark. If its weak or not blue, it wouldn't hurt to gap the plugs to spec and/or just replace them if they're old. What color are the electrodes on the plugs? Black? Tan? White? Are they wet or dry?

I hope this helps in some way. Again, I'm not a textbook

 

thanks a lot. i actually replaced the pugs a few weeks ago, gapped (first time i did that but i think i did it right using a gapping tool, fairly simple). i replaced because i wasn't sure if the old ones were sparking and then checked the new ones when they were in and wasn't sure if they were sparking either. i remember seeing some tiny yellow sparks.

i posted a question a couple weeks ago about my clutch possibly slipping. when i give throttle, ususally in third gear or higher, bike starts to accelerate but then all the sudden the rpm revs high and bike barely accelerates. i thought this might be clutch, or missfiring. right side of bike also seems to get hotter than the left side. bike also seems to not accelarte quite as fast as it used to (which was pretty fast) even before the acceleration quits/rpm revs high begins. i adjusted the clutch cable before but didn't really know what i was doing, will probably try that again, maybe pull the plugs again too and check ...