spark plug fouling

kantoniak

Posted 01 June 2012 - 06:33 PM

#21

schrode, on 30 May 2012 - 10:26 AM, said:

i gotta disagree. plenty of people run yamalube with no problems whatsoever.

if the bike ran ok at some point but now fouls plugs then it's a reed, intake, crank, etc. leak of some sort. if its' always fouled plugs then it may be jetting. you shouldn't have oil outside of your motor. figure out where it's coming from and fix it. once the leaks are fixed if it still fouls plugs then rejet.

i'm betting you've got a leaky powervalve cover. they tend to warp when the bike gets too hot.

Just going on experience. ONce the Yamalube was gone no more fouling plugs (2) on a 09' YZ 250. No jetting changes. Eitherway, I won't use it again.

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schrode

Posted 01 June 2012 - 08:26 PM

#22

kantoniak, on 01 June 2012 - 06:33 PM, said:

Just going on experience. ONce the Yamalube was gone no more fouling plugs (2) on a 09' YZ 250. No jetting changes. Eitherway, I won't use it again.

fouling plugs is a by-product of poor jetting. when you use a race oriented oil with a high flash-point your jetting problems become more obvious particularly if you're not ringing its' neck all the time. there are tons of good oils out there and any one of them can be used successfully if you set the bike up to utilize it. it's that simple; bean oil, synthetic, blend, hi/low flashpoint, 16:1 or 100:1.

yz125r

Posted 03 June 2012 - 08:30 AM

#23

okay so i went riding yesterday for a few hours and i couldnt see the oil becuase there was too much mud. and i foulded to plugs and my current plug is very oily.. im kinda tired of fouling plugs.. should i take my carb apart and put smaller jets in? i dont know what size are in there right now. is there a chart anywhere that will tell me what size i should use for my elvation?

ThumpinAway

Posted 03 June 2012 - 08:50 AM

#24

yz125r, on 03 June 2012 - 08:30 AM, said:

is it oily or wet like fresh mix gas getting on it? mine was getting fresh mix gas on it to fast to burn off and alls i had to do was adjust the floats to spec because it was allowing too much gas in

yz125r

Posted 03 June 2012 - 09:36 AM

#25

it was gas till i lowered floats but now its just oil crap

yz125r

Posted 03 June 2012 - 12:00 PM

#26

alright so i pulled my carb... main jet 360 and pilot jet 45

kiwi86

Posted 03 June 2012 - 01:02 PM

#27

I google searched stock jetting for my 2002 YZ because mine was running a bit rich, stock is a #410 main and #40 pilot. Mine is running a #430 main and #30 pilot and still running rich, so you may need to go down a few sizes on the pilot.

yz125r

Posted 03 June 2012 - 03:06 PM

#28

mine for stock is main 350 so im going to try 340 after 350 and my pilot is at stock right now 45 im going to get a 40 and 35.. i cant find any of these in stock anywhere where do i get them?

ThumpinAway

Posted 03 June 2012 - 03:35 PM

#29

bike shops dont stock most carb parts. i had to order a float gasket and this place is cheapest and cheap shipping.
http://www.powersportsplus.com/

yz125r

Posted 03 June 2012 - 04:44 PM

#30

thanks hopefully get it by this weekend!

schrode

Posted 04 June 2012 - 05:30 AM

#31

yz125r, on 03 June 2012 - 03:06 PM, said:

mine for stock is main 350 so im going to try 340 after 350 and my pilot is at stock right now 45 im going to get a 40 and 35.. i cant find any of these in stock anywhere where do i get them?

call these guys and tell them what carb you have and what you want.

http://www.sudco.com/

they have everything, but the website is kind of annoying. very helpful on the phone. $25 minimum though so get some oil or something if you don't hit the minimum with jets.

Theeebalz

Posted 04 June 2012 - 05:42 AM

#32

i had about the same problem with an old atc250r at work last week, after re doing the carb top to bottom, i finally decided to pull the plug, and would you guess what happened? the plug boot fell off, cut a piece of the plug wire put a new boot on it and it fired right up and ran great. so if you haven't try that. OH and switch to a br8es ngk plug, they're like 3 bucks at autozone. i use em and dont foul any plugs.

yz125r

Posted 05 June 2012 - 04:58 PM

#33

o and a little side note i dont know if this has anything to do with anyting but when i first got the bike i just rode it around the yard all the time and went trail riding with it and never had a problem. but when i went to the track it started fouling seems like it should be the other way around :cry:

Theeebalz

Posted 05 June 2012 - 06:30 PM

#34

yz125r, on 05 June 2012 - 04:58 PM, said:

not really, that would seem to me that your main is toorich

yz125r

Posted 08 June 2012 - 09:16 AM

#35

so should i change pilot or just main?

Dirtymutt9

Posted 08 June 2012 - 09:31 AM

#36

dont just go down one size on your main. if you are fouling plugs you are WAY rich. go down at least 2 sizes on the main. drop at least 1 on the pilot.

If i were in your shoes i would buy 3 main jets. 2 sizes down 3 sizes down and 4 sizes down. then i would also buy 2 pilots 1 size down and 2 sizes down.

dont forget that you have a needle jet in there too. make sure you adjust the needle to the middle of the clip range when you start swapping jets.

Ah the joys of jetting! I spent a solid day jetting my bike about 2 years ago and still to this day i have NEVER fouled a plug. thing runs wonderfully.

take you time, its totally worth it

yz125r

Posted 08 June 2012 - 10:17 AM

#37

well i ordered a 350 and 340 thats the smallest i could find and got 2 sizes smaller with pilot too and the needle clip i dont really know how to work with it

Dirtymutt9

Posted 08 June 2012 - 10:25 AM

#38

the needle sits inside of the slide. you access it by pulling the top of the carb off. there is a c-clip that rests in little grooves on the needle. make sure the clip is in the middle groove when you start changing your jetting.

BTW your needle is partly/largely responsible for midrange throttle response so dont neglect it.

Edited by Dirtymutt9, 08 June 2012 - 10:25 AM.

yz125r

Posted 09 June 2012 - 11:05 AM

#39

me being a &%$#@!ing dumbass i over torqued main jet and the head broke off that was the 340 i gonna put thge 350 in it for now till i get another 340.. i have no idea how to0 get it out now

yz125r

Posted 09 June 2012 - 12:34 PM

#40

okay... got it out so i have no 340 anymore so i put the 350 in and most of the spark plug but the very bottom was pretty oily a good solid coat on it.. can i ride while i wait for my 340 to come in or will this foul on me too... the bottom part of the plug was shiny clean looking brand new.. by the way i just started it and revved it for a little bit so i could get a reading of the plug

kantoniak

schrode

yz125r

ThumpinAway

yz125r

yz125r

kiwi86

yz125r

ThumpinAway

yz125r

schrode

Theeebalz

yz125r

Theeebalz

yz125r

Dirtymutt9

yz125r

Dirtymutt9

yz125r

yz125r

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