Im never buying another 2 stroke ever again, Spark Plug problems....

[Dirtykid]

Hey everyone,

I just got my 2000 RM 125 back from the shop and it seemed to be running perfectly, well it was. I rode it and it was good, then left for a week in my garage, went to start it and nothing, so I checked i had some spark but the plug was gooey and black. I changed the spark plug and it ran good again, another couple of days, and same problem, i have an irregular spark it goes super good sometimes, then not at all other times.......

WHat should i do ? my gas mixture is 32:1 and everything should be jetted right according to the shop guy..... I hate this stupid bike everyday theres something new thats wrong.....

Thanks

 

[JTT]

If your plug is fouling that bad, your jetting must be too rich and/or plug too cold. I suggest you do some reading on "how to jet" and don't just believe some guy who's never even ridden the bike. There's a great article on Eric Gorr's website on jetting and LOTS of information around here if you do a little searching.

If you think tuning issues are strictly a 2 stroke thing, your sadly mistaken.

 

[CaptainObvious]

WHat should i do ? my gas mixture is 32:1 and everything should be jetted right according to the shop guy..... I hate this stupid bike everyday theres something new thats wrong.....

Thanks

Well, there are several things that could be causing you trouble. First, despite what your dealer has told you, your jetting might be too rich. I have yet to come a cross a dealer who is willing to take the time to properly jet a bike. You'll have to take the task on yourself.

Second, 125's like to be ridden hard. If you baby the thing it's going to eventually foul plugs, even if it's jetted correctly. Keep the bike on the pipe - as often as you can. You'll be rewarded with great performance and a bike that will be kind to its spark plugs.

If you "hate the stupid bike", perhaps you're not ready to own powered equipment.

 

[Bodge]

Isnt this the kid who ran with no radiator fluid and 2x as much tranny oil in his bike then wondered why it didnt run too well? Never trust a shop to jet your bike. Go to erics site, or use the search function to learn how to jet your bike. If i were you i would check the float height.

 

[marcusgunby]

do you turn off the fuel tap between rides? as the carb might be filling the crankcases with fuel if the stop valve isnt working properly.Then when you try to start it , it will foul the plug.

 

[kx134]

"I hate this stupid bike everyday theres something new thats wrong....."

/\
I reccomend you take the time to learn how to work on the machine yourself. A late model 125 is pretty standard to work on. my 99kx, like someone else's 99cr, lights first kick every single time. You are fouling plugs most likely b/c your bike isn't correctly jetted. I think it may be time, at the very least, for
1.a shop manual
2.a new "shop guy"

good luck and like someone else said, keep her on the pipe! john

 

[jrg]

most shops that i have seen dont have enough riding area to properly jet a bike..cant jet on the stand, most shop mechanics just look up the stock jetting and figure thats close enough...i worked on a bike not long ago, kinda the same boat you are in, he had it in the shop a couple differant times..ended up with way to small of a pilot and a WAY to LARGE of a main jet..go to fmf's web sight, it will atleast get you in the ball park and you can fine tune from there. ;)

 

[Porstala F9]

-Switch to an 8 Heat Range plug instead of a 9

-Lean the jetting. Start out by one step increments. (ie: if you have a 40 stock pilot, go to a 37.5 and if its not good enough, go to a 35, 32.5, 30.. shouldnt be lower than that) Main jet = 420 stock, so try 410,400, and maybe 390. Go as rich as possible to where it is at a good point. When in doubt go rich, and of course raise the jet needle clip to the second position. Post back if you need instructions on doing these things.

-As noted, dont forget to turn off your fuel tap when you turn the bike off for the day, or for a while.

-Dont listen to dealers. They told me back in February or so when I called them regarding jetting information and they tried to tell me not to do so as if it were against their religion. Of course, I went ahead anyway and havent fouled a spark plug since then! Most of the newbies behind the counter around here dont even know what a spark plug is.

 

[CaptainObvious]

Lean the jetting. Start out by one step increments. (ie: if you have a 40 stock pilot, go to a 37.5 and if its not good enough, go to a 35, 32.5, 30.. shouldnt be lower than that) Main jet = 420 stock, so try 410,400, and maybe 390. Go as rich as possible to where it is at a good point. When in doubt go rich, and of course raise the jet needle clip to the second position.

Glad to see you took the time to learn the black art of jetting. :cool:

 

[showtime586]

Some 2 stroke are more difficult to properly jet than others. Take your time, and keep notes. Believe me, this makes the process much easier.
32:1 is a conservative ratio used by the manufactures. Most 2 strokes that I have had, were 40:1, or higher.
These are competition bikes that are meant to be ridden on the pipe. If you lug the around, you will foul plugs.
Do a little reading, and don't be so quick to get irritated. Your bike has a jetting problem, it needs your help.

 

[Dirtykid]

Cool thanks a lot everyone, Im writing this all down as i go... im gonna try get around to everything, I always turn off the fuel tap, and I think i could play around with the jetting a bit ive taken my carb a part enough times to know where everything goes, but im gonna check the plug situation cause i dont think i have the right one, maybe i should ride the girl a lil harder too, theres just not that much tracks around me, mostly trails....

thanks again everyone, ill comeback with some results......

Dirtykid

 

[MX-727]

Check this out too:

Carb Tuning Link

 

[YamaB]

I went as lean as I could safely go on my yz250 and it STILL fouls plugs... I do ALOT of woods riding and have to lug it quite a bit which I believe to be part of my problem... I've just decided to live with having to replace a $1.50 plug (buy the regular ES plugs from auto parts store) each time I ride...

- BA

 

[JTT]

Have you tried running a slightly hotter plug? I used to always run one hotter in my CR250 in the woods.

 

[fuzzy]

as I could safely go

Than you can safely go leaner! :)

 

[Porstala F9]

I went as lean as I could safely go on my yz250 and it STILL fouls plugs... I do ALOT of woods riding and have to lug it quite a bit which I believe to be part of my problem... I've just decided to live with having to replace a $1.50 plug (buy the regular ES plugs from auto parts store) each time I ride...

- BA

Thats a terrible waste of money!

What plug # are you buying? 7, 8, 9? Switch to the next smallest number heat range (hotter for ngk)

 

[MikeT]

Once you get it jetted correctly, you should never have a problem. I go through maybe 2 plugs a year and that is just because. Not due to fouling, just because I wanted to change them. You will have a distinct advantage over all your fellow riders when your bike is jetted properly. I used to get 3rd and 4th in the holeshot on a 1996 YZ125 (and I weigh 205lbs with my gear) against 2004 bikes with 150lb riders on them.

Jetting will help you more than you think!

 

[Dirtykid]

Well I played around with my air screw and ever since the last post and i havent had to change my plug yet everything seems to be good, and my plug isnt all gooey and black anymore, so i think its good for now..... thanks

 

[YamaB]

FYI -

When I bought the bike, it was already jetted at 38/160 which is CRAZY lean... I've been running the br8es plugs, but I might try the br7es ones...

- BA

 

[CaptainObvious]

How clean is the inside of your pipe and when was the last time you repacked the silencer? While 160 sounds OK for a main, 38 seems a bit thin on the pilot circuit. However, if you have a combination of a dirty air filter and a clogged exhaust system, a 38 pilot jet seems plausible.