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2017 Yz 125 fouling plugs and climbing idle

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I recently bought a brand new yz 125 and as it has been a fun bike it seems im changing plugs every other day, im running 32:1 mixture the whole carb is stock, the only thing i have done to the carb is turn the idle screw in, im riding the bike in the band and hard so thats not a problem but if i ride out of band for just 30 seconds to get through a bunch of trees or something itll start to load up and when i take off itll be a little blubbery then take right off and go when i come to a stop sometimes it will idle a nice steady idle but sometimes when i come to a stop itll act like it wants to die and feel like its on the lowest possible idle setting, that bothers me alone bc im ocd but then if i get off of it for 10 minutes to get a drink and come back to get on it i have to let it sit and give it gas for about a minute before i take off or it will foul a plug, thanks for any advice i can get

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Also if i start it in 1st with the clutch in and give it gas and get it started it wont even try to idle it just revs and goes all the way down and dies it does the same thing in neutral sometimes

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Stock brass is pretty fat. Also, check the air mixture screw and see what it is set at at. Not sure about the 17 125 but a good start (and depending on your altitude/humidity/temperature) 1.5 out from softly bottom is a good start. 

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4 minutes ago, medalheatpistons said:

Tempature is 90 degrees in us i have no idea about the altitude or humidity i dont really believe in those things playing a big role

:jawdrop: 0-5,500 and 5,000 to 7,500-10,000

Bikes come out of the factory 0-5,500 but your stock jetting is fat for even that.

Ok, Let others chime in...

Carry on. 

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I have a 16. I run a pro circuit system and have been running Sunnoco110/93 with Yamalube at 32:1. I am coming off a 450 and ride in the sand so my right wrist stays locked. The plug is a nice brown color with stock jetting. I fully expected to rejet the bike as they come a little rich but it wasn't necessary for the factors stated above.

Rejet your bike and rethink your statement on altitude and humidity.

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11 hours ago, P84ONE said:

:jawdrop: 

I'll second the :jawdrop:.  Don't let science get in the way...

That said, if you don't know your conditions, knowing where you ride gets us most of the way there.

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13 hours ago, medalheatpistons said:

Tempature is 90 degrees in us i have no idea about the altitude or humidity i dont really believe in those things playing a big role

I'm 3,000 feet above sea level. Bike came with stock carb settings (obviously), and for the bike to run even relatively close to decent in 95 degrees I had to go from a 40 pilot to a 37.5 and 430 main down to 405. Air screw varies.

I don't know where you got this idea that altitude and humidity don't play a role but if you stick with this notion get used to your bike never running well. Or worse, run it too long too lean and your bank account will feel the repercussions. 

Also, your posts are hard to understand. A period every now and then and basic grammar skills may help people understand you. 

Edited by 505 YZ125
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9 minutes ago, 505 YZ125 said:

I'm 3,000 feet above sea level. Bike came with stock carb settings (obviously), and for the bike to run even relatively close to decent in 95 degrees I had to go from a 40 pilot to a 37.5 and 430 main down to 405. Air screw varies.

I don't know where you got this idea that altitude and humidity don't play a role but if you stick with this notion get used to your bike never running well. Or worse, run it too long too lean and your bank account will feel the repercussions. 

Also, your posts are hard to understand. A period every now and then and basic grammar skills may help people understand you. 

I ususally give people the b of d in case they are on their phone. I ramble a lot, miss periods, eyes are not great, etc. but out and about I never miss a good set of

( . Y . ) 

:thumbsup:

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5 minutes ago, P84ONE said:

 

( . Y . ) 

:thumbsup:

^^^^^^ this. 

Edited by 505 YZ125
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23 hours ago, medalheatpistons said:

Tempature is 90 degrees in us i have no idea about the altitude or humidity i dont really believe in those things playing a big role

Haha.  You don't eh?

Your bike is too rich.  It's no mystery.  Either your jetting is too rich , or your float level is too high. 

For example, my YZ250X came with 178/48 main and pilot jets.  I'm not that high up, only about 4500 ft.  To get it to run right I had to drop one size on the pilot, 2 clips on the needle, and 2-3 sizes on the main depending on season and temperature.  Because science...

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15 minutes ago, medalheatpistons said:

Cleaned the air filter and threw a new plug in it and runs perfect now so that "because science" claims not really true for me as i said

Look man. You may be real close to sea level where you are and that's why the bike is running ok. 

But altitude, humidity, and temperature play a huge role in how jetting affects performance. That's a fact because... well... science. 

To suggest that they don't is acenine. Your suggesting that thousands of people on this site with legit experience are "wrong" for taking those factors into account when they jet their bikes. And not to mention plenty of reputable sources that put out jetting suggestions (like pro circuit, no need to discuss their credentials).

and anyways, you asked this site for advice/opinions. Do with it what you want. 

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24 minutes ago, 505 YZ125 said:

Look man. You may be real close to sea level where you are and that's why the bike is running ok. 

But altitude, humidity, and temperature play a huge role in how jetting affects performance. That's a fact because... well... science. 

To suggest that they don't is acenine. Your suggesting that thousands of people on this site with legit experience are "wrong" for taking those factors into account when they jet their bikes. And not to mention plenty of reputable sources that put out jetting suggestions (like pro circuit, no need to discuss their credentials).

and anyways, you asked this site for advice/opinions. Do with it what you want. 

A dirty air filter and a old fouled plug is science. :thumbsup::jawdrop:

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your first post mentioned fouled plugs , caused by..........what for it ...........

1: rich factory jetting

2: altitude and temperature

like it or not but altitude and temperature play a massive role in carb jetting and even more so on 2 strokes

0-1500 ft , 1500-3000 ft,  3000-4500 ft and so on all require different jetting then you add in temp and it gets even more fun

ALL factory bikes of any brand are rich , why....... because they dont want you to blow it up under the limited warranty they come with

all of them are jetted to run at sea level ( 0-1500 ft ) and 70-90 degrees

if you think this isn't true then you should by some shares in a spark plug company because you will be changing a few

my bike wouldn't last an hour on a plug  on standard jetting but jetted correctly ....2+ years and i only change it because i can

i'm guessing from you comments your a castor oil kind of guy as well

 

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That's a dirty a** filter.  Good lord.  If there's enough dirt in it to suffocate the motor, imagine how much of it actually got through.

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If you have an iPhone get the yz jetting app 

 

since yz125 are jetted fairly good from the factory this app is awesome.

No need to know what you are doing !

it takes your locations current temp/ altitude / humidity / and gives you the proper jetting.

Is jetting as good as it can be? But it pretty dam good especially if your bike is still completely stock.

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