Sophomore Rider
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Post by dyoung1167 on Dec 7, 2019 16:26:46 GMT -5
I really really hate the style of boot that comes with these that only has the little spring wire to grip the tiny threaded end of the plug. I am having a hard time locating one like a car style (snap on) cap so i used one from a car ( and yes I added the hourglass style adapter to the plug). seemed great at first but I was also dealing with cheap crap muffler that fell apart after a week so the first bit of use of the plug wire was with straight header exhaust without muffler and seemed ok, now the new muffler wich really has no more resistance or backpressure (just takes the loud cracking sound out but doesn't really muffle the overall loudness) anyway, i now seem to have a bit of inconsistent spark/firing that i now hear and feel but didn't when no muffler at all. is the style of wire on my new plugwire ok or possibly a different resistance than the coil normaly expects to see or something? I know i need to address a bit of running lean but......?
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Post by chewbaca on Dec 9, 2019 0:05:58 GMT -5
I did the same thing with my spark after the original vibrated itself apart
it works far better than oem and won't shake apart
back pressure is only required inasmuch as you don't thermaly shock the valves and burn them out.
Also exhaust does not effect the mixture like messing with the intake side does
but the mixture does effect the exhaust
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Sophomore Rider
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Post by dyoung1167 on Dec 16, 2019 14:49:00 GMT -5
Yeah, I know lean gets to popping (backfire) and it's more the low end so I'm thinking my idle jet is a touch small and ran fine (still with backfire) for a couple of weeks with just open pipe where the muffler flange broke off while waiting the muffler and new header, this started about 3/4 days after the new exhaust that actually adds zero more backpressure than it was without. Seems oddly missfiring or something as it is not an even/steady sound, not counting backfire. also seems nice and even when first started though not necessarilly after giving throttle but a little irregular after warmed up even at idle. I've had pick-up coils go, but they just go as in runs then doesn't. no inbetween for me yet but that doesn't mean it isn't possible. Maybe I'll pull the flywheel and give it a look see as I have heard (long in the past) about dust and crap fouling the magnet or something to that effect. Going to try one the (high tech/performance though probably not really with the oddly even good bad reviews) cdi's I just received today.
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Post by wheelbender6 on Dec 18, 2019 20:27:18 GMT -5
The engine in my motorized bicycle was skipping, so I replaced the plug wire with a silicone wire from my Ford Escort. Looked stupid, because the Escort wire did not have an elbow in it, but it worked great. It was a 49cc 2 stroke.
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Post by chewbaca on Jan 8, 2020 12:31:12 GMT -5
backfire is when flame pops either from the pipe or the carb in a one cylinder motor it is caused by a leaking intake valve allowing fire into the intake plenum full of
mix, a leaking exhaust valve pumping mix into the pipe followed immediately buy hot exhaust usually won't even run if it is that bad as a single so not very likely, or if it is running rich do to the idle circuit being extra rich. A normal stock exhaust pipe is so long and bulky that the rich exhaust is either cool enough not to burn when it hits the O2 rich air or it has a cat.
so check cam timing and valve gap
its not likely to be caused buy an electrical problem
because with only one spark plug wire it can't cross fire and there is no adjustment to mess up on the pickup
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Post by grumpyunk on Jan 23, 2020 10:06:03 GMT -5
You get popping out the exhaust for two reasons that come to mind. Fuel/air mix that was not burned in the cylinder finding some glowing particles in the exhaust, and BAM. You also get popping when you close the throttle while running at a good high rpm. The mix can get too rich because airflow is limited by the butterfly, but apparently there may be enough extra air in the exhaust/muffler to light off a burnable mix.
Backfire from the carburetor is generally caused by a lean mixture. I have not had that one explained to me..., but have seen it occur on car & truck engines.
tom
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