How To See If A Two Stroke Is Running Correctly!

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

100 thoughts on “How To See If A Two Stroke Is Running Correctly!

  1. This is an awesome video. Very informative. Glad to say I've learnt something new again. Every day! Thanks buddy you are a wealth of information when it comes to bikes.

  2. I ride a 17 yz250 at 28:1 no matter what I ride. Dunes trails whatever. Never fouled a plug yet trail riding at that ratio. All in the jetting. I favor thinner oils at heavier ratios than "racing" oils at 50:1. You won't have residual oil at the bottom of the crank at 50:1 unless your off the pipe most the ride.

  3. Hey my 70cc bike doesn't start cold by kicking at all. It starts warm 1st kick. I have to push start it and it roughly starts. Top end is good and I've changed the plug. Any advice?

  4. I was told and want to know about the tip of the porcelain/insulator, being black means rich, or cold plug. tan just right etc. No ?

  5. If I fully open the throtle, my engine holds out, does this mean my mix is too rich? Since it can't be ignited the right way anymore?

  6. When you're doing the chop test after you ran it wide open through the gears and shut the engine off you need to hold the throttle wide open for a correct plug reading, just saying

  7. WC !!!


  8. I like two strokes but I mean I wouldn't be surprised if they get banned in the the next 4 years because of all the gas they use and smoke they let off

  9. I got an 08 kx100 and iv tryed everything and bike keeps bogging down when I give it gas its not the carb I thing it might be the pickup coil but im so done now

  10. I have a Husqavarna te250 and itโ€™s a used 2016 model. I found little pieces of aluminum inside of the spark plug and the plug was not working either. My uncle says it means the top end is most likely destroyed or going to be but does anyone know what this means?

  11. Hi cameron, I was wondering if you could advise me, I was doing wheelies when my bike cut out and wouldn't start unless I bump started her. She won't idle just cuts out. The chain is looser than it was, I thought it might be a bearing but haven't really got a clue. Please help

  12. Great video man, lots of valuable information in here. Two questions about your bike: Where did you get your graphics kit for this bike? Also, the red anodized washer between the gas tank and the rubber frame isolator, where did you get this washer? Just curious as I would like to purchase these pieces for my 01 cr125.

  13. So basically since u didnt let the bike run long enough the first time u couldve just explained it with the old plug

  14. What are the differences of rich and lean soundwise? Im having a problem with my two stroke but im nor sure that is it running rich or lean..
    Thanks for the help!

  15. Yeah thanks I'm cheating I have a racing go kart and I was eves dropping to learn a little about jetting a two stroke and mainly looking to see what tips u could give on reading the plug,ah plugs I see I must sacrifice at least one wow,thanks…my go kart a rotax 125cc two stroke some of the info mite apply,I was going to buy a 7 8 9 plugs and work the pilot and the main a little I'm really looking to get a cleaner low end response,my mid to top is insane,but low end is pretty boring,thanks for the help dissecting a spark plug read I mean really…piece

  16. Hey would love too see a jetting video. Just getting back into dirt biking with my son. Working on making his CR85R rip

  17. Ist it running just right? Easy, take out your earplugs, put your head near the expansion chamber and if when you rev it up it makes the back of your throat itch, it's spot on.

  18. I have a 1989 CR125R , love this bike ,and your video taught me lots about ignition and fuel mixtures . I dont see many bikes of this year ,why is that ?

  19. Ahhhhhh if it where only that easy to get to my plug. I have to take my seat and tank off to get my plug out. 01 Service Honda 500af. I spent 10 minutes my 1st time changing a plug before I finally took the seat & tank off.

  20. When it comes to spark plugs… what would you say is going on, if the tip and insulator are slightly green in colour?

    Itโ€™s definitely not headgasket/coolant as itโ€™s still all clean in the rad and overflow .

    Any help would be awesome! ๐Ÿ˜Ž

    Love the vid. ๐Ÿ’จ๐Ÿ’จ๐Ÿ’จ

  21. Would love to see the jetting video I have been Struggling to set my carb on my 1995 Honda cr125 i did a complete rebuild of this bike and it bogs at the end of each gear st full throttle love your videos you make wrenching look easy

  22. If anyone noticed he said a little lean for power on the track like32:1, in which case rebuilds are gonna need done anyways. Riding mix 40:1. Basically if you aint racing pro a runnig the shi out of it go 40:1 and it will run for years as long as you change plugs and open it up once in a while.

  23. Hi friend I am a fanatical subscriber the truth left me unpredicted as you disassemble and arms your motorcycle without problems. I would like to ask you a question Do I have a CR80R HONDA that Mixture of Gasoline and Oil is the one that carries correctly? Thank you friend, God is great!

  24. Hey bro appreciate your videos,
    Question: Kick back / Timing my Husqvarna 250 (1994) some times fastveasy kick start and then leg whip, your thoughts?
    Note Iโ€™ve had CR 500s and never had this happen but other then said โ€œ u better be careful kick backโ€ Iโ€™d always laugh because it would start easy for me n no kick backs ever ๐Ÿ‘๐Ÿผ Appreciate the expertise bro๐Ÿ‘๐Ÿผ
    Iโ€™m 52 now, saving my leg lol

  25. Wc ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผโญ•๏ธ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ๐Ÿ™๐Ÿผ

  26. When you started reving i thought i could smell the 2 stroke through the screen realising i got a spark plug in my hand, always great info Cameron thanks againโœŒ

  27. It gets hard with NGK with all the resisted plugs when most of their plug caps are resisted why do we need both? I'm not watching tv when I ride and I don't care if my engine is interrupting my neighbours scat porn to be honest…..why resisted plugs and resisted caps especially on 2 strokes? And fuels these days have messed up plug readings as well good video comming from someone reading books with black and white photos in books when fuel still contained lead lol

  28. Hey Cameron, your cr 250 is looking mint;
    Trying to convert mine from mikuni to keihin pwk , struggling to cure its bad jetting (low end ) tried swapping pilot jet etc, itโ€™s at 55pilote , 172 main , second clip

  29. ุฃู†ุง ู…ูŠูƒุงู†ูŠูƒูŠ ุฏุจุงุจุงุช ุŒ ูˆู„ุง ุณูŠู…ุง Panchi ู…ู† ุงู„ู…ู…ู„ูƒุฉ ุงู„ุนุฑุจูŠุฉ ุงู„ุณุนูˆุฏูŠุฉ ูˆุฃุชุงุจุน ู…ู‚ุงุทุน ุงู„ููŠุฏูŠูˆ ุงู„ุฎุงุตุฉ ุจูƒ ุฃูˆู„ุง ุจุงูˆู„ ุดูƒุฑุง ู„ูƒ | I am a tank mechanic, especially the Panchi from Saudi Arabia and I follow your videos first Powell thank you โ™ฅ๏ธ ๐Ÿ‡ธ๐Ÿ‡ฆ

  30. In one of your videos you said something about a slow return to idle being affected by slow jet was that to big or to little of slow jet?

  31. Your oil/fuel mix of 32 to 1 is in liters or gallons? Kidding, rsrsrs … Very fat. I use 50 to 1 on syn. And kindda wastefull way to read a plug, by ruining a brand new iridium one.

  32. Man my cousin worked in a shop for years and he did my bike fully blown bottom and top rebuild project. It starts first kick when it's cold everytime without the choke. It idles and never fouls plugs unless it's my fault. Just get a good mechanic and you'll be good as gold.

  33. I don't think it's worth checking all these kinda unecessary things and ruining a perfectly good spark plug when you can just tune it by sound, RPM and smoke and forget about all this other BS.

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