97 rm125 fouling plugs

[MillerfamilyRacers]

Hi all I posted this in my local forum but I was told to give it a try here in 2 stroke. Well here is the problem I have been having.

Husband bought son a RM 125 from a local seller. the problem with it when we bought it is the kid that rode the bike blew the cylider and it needed to be re honed and all the bike was in parts when we got it.

Here is what we did:

Cleaned the bike up took the bike completely apart. cleaned out everything and bought the new gaskets and the whole nine yards. Got the cylinder re honed and dipped. then we put the bike all together after a full clean through of everything from tank to all hoses.

Things we added to the bike:

A fatty Pipe and a FMF muffler.

stock sproket

and a new filter

After all that done the bike was put back together and the plugs keep fouling after a hour into the ride. we noticed that the pipe will not get hot at all and it sounded as if the bike was floodin out. made sure the choke was not stuck it was all fine just keeps fouling plugs @ 28.00 a pop!

Ok I just was informed that it may be the jetting? because I replaced the muffler it may be that? So I changed the jet to a 168 from a 170. I also checked the float and the seat it was fine.

STILL FOULING!!!! ANYONE please help me! I have exhausted all my knowledge on what is making this bike keep fouling plugs?

Thanks for reading!

Mom in need of help

[Dirtymutt9]

use an NGK iridium spark plug, they are much harder to foul, also, make sure that your crank seals are good. you could be burning tranny oil!!!!!! check your crank seals.

what premix are you using at what ratio? what is the position of your needle jet. are you fouling plugs when lugging the engine out of corners? need alot more info to figure your problem out

LOve

dirty

[zuuk]

I actually have the same bike and have gone through the same process. Basically, after installing a new piston I have been having problems with wet fouling. I have just replaced the reed petals, and have yet to run the bike to get the jetting dialed back in.

Also.... and I am thinking this might be a source of my problems... I changed spark plugs from an NGK BR8ES to the Iridium BR8EIX with the fine wire. Once this fine wire is fouled, there is just no getting it cleaned and operating properly again... very weak spark. So I am also going to go back to the BR8ES plug that was in it when I first purchased it (used).

Either of the plugs above will work for you and are much cheaper than the $28 ones. Iridium ones are around $11.

I am going to dial in the jetting this weekend and confirm that the fine wire Iridium plug is part of my problem. I will definitly get back to you on this and let you know what I find.

[MillerfamilyRacers]

Hi Thanks for the reply! Ok this is what has yet happened after posting the help needed. I am using a NGK R6918B-8 And it is a new plug I installed. I replaced the carb after changing the jetting from a 175 jet to a 168 jet and I checked and just replaced the seals. and the setting I am not sure what that is but here is a shot in the dark I set it at 4 that is the stock setting. Well since then I started it up and there has been some new changes! I did not fould the plug right away we will go riding tomorrow I will let you know how it goes. It seemed when riding it up and down a few times it ran much much different than before.

Before the pipe would not even get warm to touch at first even after a 1/2 hour ride and it seemed like it was holding back. now It feels like lightweighted and running great we will see though it may take a hour or more to break it in. Well thanks again I am sure I will be posting another help me thread very shortly! lol Thanks!

[MillerfamilyRacers]

yeah that would be of great help! I got the bike back together and we will take it for a ride in Walker Valley tomoorow and test it out. Let me know I have heard alot of similar prolems with the RM 125 fouling plugs probs! Picky picky picky bike lol But it is all good! I learned that when u change the pipe the jets really are finicky when doing that! that I learned! Thanks again for your inquiry

[MillerfamilyRacers]

Ok I took the bike for a test ride @ walker this weekend. After changing out all the things I bought over the week and all I thought my days of fiddling were over. Ahhhhh yeah not a chance! ? Ok here is what happened. Ok The bike started right up and we were off riding the trails. after an hour into riding again!!!!!! ? the bike fouled! ? towed bike back to the trailer got home pulled the thing apart again!

NEW FOUND: Drained the oil and what do u know WATER!!!! water all over the spark plug junk! Oil fouled! crank was filled with dirt and water and oil! oh god I just about giving up on this bike! So I have one question I tried to take off the main drive not the one where the basket is but the other one the main one how the heck do I take that off? is it reverse threaded? help me!!!!!!!!! I need to change out the crank seal. but I can't get that bolt off!

whish me luck please help!

Mommy Mechanic lol

[iamspencer]

use an NGK iridium spark plug, they are much harder to foul, also, make sure that your crank seals are good. you could be burning tranny oil!!!!!! check your crank seals.

what premix are you using at what ratio? what is the position of your needle jet. are you fouling plugs when lugging the engine out of corners? need alot more info to figure your problem out

Hey, i saw this lady way upset at the cost of the 28 dollar plug, for some reason its 38 at my local shop and i canot find it on the net fo cheaper, is there a number to this iridium plug you say works? and is it realy true if the 38 dollar plug gets oil on it and fouled its dirt and will never work again?? please im freakin out because all i wanted was to sell this bike and now its got a fouled plug im not willing to buy another 40 dollar plug

LOve

dirty

[Theeebalz]

you're going to need an impact or impact driver to get that bolt off, are you getting water in from the cooling system? this is one of the years where the pump was inside the cases if im not mistaken. did the gasket maybe break around where the impeller sits in the cases? or is the head warped? cylinder warped maybe? how much coolant left is what i really wanna know.

[92rmx250]

The jetting is sensitive its worse if you add a rad valve had lots of problems getting it sorted after that great bike dont give up