all right what's happening guys today I'm gonna be talking about how to read a
spark plug on Artie stroke now this is more geared towards a two stroke but you
could apply it to a four stroke as well so there's a bit of confusion out there
where exactly to read the spark plug I and what are the indicators of a lean or
rich condition and there's also a lot more you can read from a spark plug to
like ignition timing detonation heat range see if the spark plug is too hot
or too cold for the bike so before we start definitely want to
make sure you have a couple new spark plugs on hand because old spark plugs
will not work for this and so let's jump right into it all right the first test
we're gonna do here is checking the overall JD the bike just see how the
bike is running overall and then later on we're gonna do a chop test as well so
to check the overall jetting of the bike we're gonna install a new spark plug
like I mentioned earlier run it for thirty minutes pull it out and we'll be
able to see a ton of information here on the spark plug it's really valuable
stuff so the first thing we're gonna look at is obviously air and fuel ratio
and then on to stroke the oil and fuel mixture and then we can also look at
ignition timing see if the spark plug is the right heat range if it's too cold or
too hot for this bike and then we can check for detonation as well so keep in
mind doing this test will only give you a general idea of how the bike is
running overall it's not going to tell you if your main jet is too rich or too
lean if your pilot's do extra to lien or mid-range you with your needle if that
is one way of the other and it could mask a really lean or
really rich circuit so by doing this test you're not gonna know if you're
really leaning up top or really lean down low but the test we're gonna do
later on called the chop test will tell you exactly where you're at with the
main jet whether it's to lean to rich or just perfect before I go any further I
got to give a big big THANK YOU to works connection for a spot through the
channel they supplied me with this bike stand and a ton of billet parts for that
cr250 bill that I'm working on so what I like about the stand is super well built
really stable and then it's got this block you can put it wherever but
especially on a bike like this 125 where the bottom of the brain
isn't flat and it doesn't want to sit flat from the stand you know a lot of
times I'll put the bike on a regular stand in the front wheel would be on the
ground yeah this is kind of kind of makes it difficult so I've got both
wheels off the ground which is obviously what you want with the stand and it
makes a lot easier for working on it's actually worth connections sent over a
bunch of sticker packs here for me to give away and so comment down below I'm
gonna pick some you guys just send these thicker packs off to you so comment down
below wc4 works connection and i'll go through and pick five you guys and send
you one of these thicker packs so good luck with that all right I'm gonna pop a
new spark plug in the bike run it for 30 minutes come back pull it out and take a
look at it
so after 30 minutes of running the spark plug in the bike there's quite a bit we
can look at here the first thing is gonna be the overall jetting of the bike
and we can read that here on the flat surface so a tan color is gonna indicate
a good mixture if it's black that's gonna be a rich and no color would be a
lean condition so this looks somewhat tan maybe leaning on the edge of no
colour so I would say that this bike is just a tad bit lean but that's where
it's gonna make the most power is on the leaner side of things so not a big deal
looks pretty good there and then next up is to look at the oil deposits from the
premix so I mixed my fuel at 32 to 1 which is great for 125 on tracks and so
wide open most of the time but on trails you definitely want to go like 40 to 1
or even leaner than that so there is a good amount of oil here on
the threads and a tip I wouldn't say it's too much oil so it looks like 32 to
1 is about right for this bike on the track but if there's any more oil than
what's on there right now I would bump it to 40 to 1 and obviously if you're
fouling out plugs you need to go with a leaner premix ratio another thing we can
look for is that nation or pre-ignition if any of that exists there's gonna be
some melting here between the electrode and the insulator on this spark plug I
don't see any signs of that so another sign of detonation is here at the bottom
of the insulator underneath the threads there's gonna be some black or silver
specks so you need to cut the threads off and I'll actually be doing that
later on in the video to do the chop test so I'll explain what I'm talking
about there what I'm gonna look at now is ignition timing and you can read that
from the tip of the electrode so the lighter colour should be less than half
a millimeter from the tip with this plug you can't really tell I don't think I
ran it long enough to get that lighter colour to show up but if the lighter
colour is more than half a millimeter from the tip you'll need to retard the
ignition timing and the very last thing I'm going to read here on this spark
plug is the heat range and we can check that out
here on the tip so if the plating is burnt on the end of the tip that means
the spark plug is too cold for that bike and if it's burnt here at the base that
indicates the sparkle look is too hot ideally it should be burnt right here on
the bend of the tip on this spark plug can't really tell exactly where the
plating is burnt once again I don't think I ran it long enough if anything
it looks like it's burnt more towards the base so that would mean this spark
plug is too hot for this bike and so how the heat range works on these NGK spark
plugs is the number here br9 eg the nine indicates this is a colder style plug
eight is standard and seven is the hotter style so this being the colder
style plug doesn't really make sense that the base here the plating is more
burnt at the base but I'll have to run this plug some more and then check it
out again see if this is too cold or too hot for the bike now it's time for the
chop test this is the absolute best way to see if your main jet is the right
size or not so what we're gonna do is have an old plug in the bike warm up the
bike take it out put in a brand new spark plug then go through the gears
shut the bike off and let it coast to a stop pull out the new spark plug cut it
apart and check it out
so the reason why I have to warm up the bike with the old plug is right when I
start the bike with a new plug to do the chop test I'll have to go wide open and
obviously you don't want to do that with a cold engine pop in this new spark plug
so like I was saying before I'm just gonna fire up the bike and immediately
take off go through the gears that full throttle and once I reached say a third
or fourth gear pull the clutch shut it off let it coast and pull the plug out
after that
it's gonna put some plug in the vise chop the end off so we can look at the
insulator at the bottom all right so you can see I've got the spark plug split
apart and what we're looking for here on the insulator is a brown or a tan ring
and that ring should be two millimeters thick if it's thicker or it's black
that means the manger is a bit rich or if it's whitish and less than two
millimeters that'll indicate a lean condition I'm gonna go ahead and measure
it with the set of calipers here I'll show you what two millimeters will look
like so it looks right about two millimeters pretty dead-on maybe a
little bit thinner which that's what I would prefer you know being a little bit
leaner like I said earlier a tad bit lean builds more power so yeah it looks
pretty good this is kind of a tannish a little darker than tan color so
everything looks really good on this insulator here and one thing I was
referring to earlier is detonation so you build the tail here on the base of
the insulator there's any black or silver specks that will indicate some
detonation see if this plug has any there's a little bit right here it's
hard to tell if that's from taking off the threads off the plug or if it's
actual detonation but not really enough to be worried about you guys enjoyed the
video make sure you drop a like down below and hit that subscribe button too
and don't forget to enter that giveaway for those works connection stickers as
well and another thing if you want to see me do an in-depth booster
getting video make sure you let me know down below in the comments section
alright thanks for watching guys and I'll see you in a future video
keep it Prime