Please read my plug

[yzrider383]

06 yz250. This plug was taken after a wot 5th gear pull yesterday. The bike feels lean with a kind a deep bog or just throaty sound at any throttle other than when i clutch it and its sceaming. ...but has spooge in the end of the silencer and at the joint between pipe and silencer. I apologize for starting another thread just about my plug but I'm not getting many replies on my help thread. PS this is bone stock jetting (50,n3ew-2,178) at 70°f around 1200 feet elevation. Thanks in advance...

[Cynictis]

I'm kinda bad at doing this, but it looks hot / "frosty" - is it hanging RPMs? Also, this shows my level of ignorance to the subject, but did you cut the threading / ground tab off?

[Bremer120]

Yeah to me it looks lean. Maybe go 180 on the main. I just had to raise my needle from position 2 to 3 last time I went to practice. Maybe try that too.

[BDubb106]

Slightly lean but not by much. 

[yzrider383]

OK I will go up on to 180 on main and probably also move the needle to the 3rd clip. I just found it hard to believe that I would need to be richer at these warmer temps.. Especially since 50,n3ew-3,180 main was where it was when it ran awesome at 30°f

[yzrider383]

I'm kinda bad at doing this, but it looks hot / "frosty" - is it hanging RPMs? Also, this shows my level of ignorance to the subject, but did you cut the threading / ground tab off?

Sorry didn't see your post last time. Yes that is the plug with the threads cut off. And no that's what seems so strange is it doesn't having a hanging rev at all in fact it actually seems the revs fall quickly because the bike is always working to rev..

[mrjata]

really looks pretty good, I would lean toward a bit more of a wet cardboard color.  In 2 strokes, error on the rich side.  Plugs are cheap, top ends are not.

[yzrider383]

I also wanted to add that my threads were wet...but the pic I posted I don't feel do the plug justice. To me it looks a lot whiter than the pics show

[yzrider383]

[MANIAC998]

With today's questionable fuel, most of us adjust our jetting by feel, not plug color. Today's fuel has so many crappy additives, that they can dis-color a sparkplug and throw off your judgement as to which way to jet your bike if you go by the sparkplug color.

[YZerman]

When's the last time you had your muffler off and looked at the packing? If it's saturated with oil etc, that can affect how your bike runs and make it hard to set up your jetting. At your elevation and stock jetting, I would think running rich would be more likely. What's your air/fuel screw set at?

[BDubb106]

With today's questionable fuel, most of us adjust our jetting by feel, not plug color. Today's fuel has so many crappy additives, that they can dis-color a sparkplug and throw off your judgement as to which way to jet your bike if you go by the sparkplug color.

You are correct. The head and piston will tell you more than the plug. 

[SellYour4Stroke]

Plug readings arent a very accurate way to jet unless you run them at a constant throttle and load for extended periods. And even then its completely subjective. "Oh thats not chocolatey brown enough" "oh mine looks like a paper bag, so its good"

 

It takes experimentation, time and experience. Jet it until it you lose some performance then come down. Something worth noting is that our YZs dont need a huge jetting change in most cases. A couple sizes or so.

 

Lots of people run jetting recommended by pipe manufacturers, buy a jet kit, or run jetting set up by another person with similar performance mods.

 

You may have another problem, my friend. Ive had a 99, 01, 05, ,13, and havent had any weird bog under those conditions with stock jetting.

 

Hard to diagnose over the internet. Run er til she blows then buy a DI '15!

Edited June 1, 2014 by jeffdanger

[yzrider383]

When's the last time you had your muffler off and looked at the packing? If it's saturated with oil etc, that can affect how your bike runs and make it hard to set up your jetting. At your elevation and stock jetting, I would think running rich would be more likely. What's your air/fuel screw set at?

Packing is new I just replaced it last week. I have tried all different settings with the airscrew and with different pilots. Edited June 1, 2014 by yzrider383

[yzrider383]

I definitley rack my brain with this bike trying to find out if there is something else wrong. But I've done everything I know how to find an answer and come up dry. I went to the 3rd clip on the needle and a,180 main for this mornings race and it ran better I think....it seemed to light up quicker for the most part but still had the bog until i got on the pipe but under a load it seemed to be hard to get it to come onto the pipe. I don't know guys I'm sorry I'm just about done with it. I've had the bike for a good while and even tho I love yzs this one has never ran great no matter what I do....especially compared to everyone else's. Do you think there is any chance that I've got an electrical problem somewhere?

[mrjata]

Hummm????  Just a SWAG here, check the timing.  Might make sure that the power valves are free and working.  Tons of variables here, what reeds do you have?  Any modifications?  Gearing?  

 

Stay with us, we all, here, will get it figured out for ya.  Eliminate one ting at a time.  Optimize it and move on.  DOCUMENT everything!!!!!!!!

 

Keep plugging.

[yzrider383]

Hummm???? Just a SWAG here, check the timing. Might make sure that the power valves are free and working. Tons of variables here, what reeds do you have? Any modifications? Gearing?

Stay with us, we all, here, will get it figured out for ya. Eliminate one ting at a time. Optimize it and move on. DOCUMENT everything!!!!!!!!

Keep plugging.

The timing is set to stock .007btdc with a dial gauge, it has boyesen pro series reeds on the stock block with stops removed, power valves are all new parts and work good, gearing is 14/51, and the only mods are a 3mm pipe spacer , FMF shorty silencer, and rb designs head mod (corrected squish). I appreciate your enthusiasm bud but I've been plugging away at this bike for a good while with nothing making much sense.

[mrjata]

just grabbing here.......try this simple test...pull the choke out just a little bit when you wick it open and it sounds "boggy".  might be able to tell you if you need to fatten  it up a bit, which I would anyway.

 

I just re-read your initial post....fatten that sucker up!  I have never run stock jetting on anything except my Stihl weedeater.  Up 2 on the main, maybe up 1 on the low speed and maybe up one on the needle, maybe 2.  All pipe mfg. tel us to fatten up.  Now your goal is almost dry dirt color,

 

 

Remember you want dry brown, not wet brown.  Dry is burned, wet is , well un burned.  I think you might be flirting with a lean out condition.  2cy should almost blubber and spit.  Ok, not as bad as an alcohol motor, but that is bifferent.

 

Get that girl off her diet!  Feed that thing, FEED IT!

[yzrider383]

Its weird it seemed like going to the 180main and 3rd clip on the needle helped power and less of that deep thraoty sound while opening the throttle all what seemed like all openings..but it also seemed as tho it was harder to get it onto the main jet if the bike was under a load.... Make any sense. BTW I pulled the plug again last night and it was still really really light colored. But the threads were wet.. Just remembered yesterday that lately I just recently tried not using race gas. I usually mixed at least 1gallon to 3,sometimes as Much as 50/50 always at 40:1 with klotz r50. But lately I tried using straight 93. Maybe I should go back to mixing some in because I don't know how much richer if will make the bike but maybe it was enough for me to question why I have had to go richer this summer. Idk nothing makes sense as I said before. Bike seems to have characteristics of lean and rich at times. Can any of u hold your bike wide open on a stand? Seems others can do it and it will only go so high and then smoke like crazy as the main is rich enough to bog it down. I still won't do that on mine...itll rev to the moon. Just some thoughts.

[tribalbc]

You're lean especially since you say it is worse under load. I would test for an air leak.