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fouled 3 different plugs/please help

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Ive gone threw 3 different plugs on my 97RM250, hotter plugs and normal plugs and fouled them all. My latest plug is the NGK R BR8EG, it worked fine for one FULL day ride, next day ripped around for an hour and bogged and died and couldnt get it to start again,same thing that always happens. My plugs all look identical when i take them out, basically looks like i dipped my plug into a cup of oil that goes down all the threads, and where the spark happens its dryed black. The second shop told me the computer says my year bike needs a hotter plug, the third place sayed the same thing but recommended the BR8EG:banghead: Im VERY frustrated and wanted to see if there was any reason behind this. I do all the normal maintence and run 32-1, please any help is appreciated...

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You need to rejet your carb. Start with your float height and go from there, you should be running a BR8EG.

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I had my carb re-built and rejetted at Screwie Lewies in AZ about a month ago, it runs fine when it works, i would believe they made sure everything was fine before finishing...? I am running the BR8EG plug

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Is there a lot of splooge coming from the exhaust? What type of oil are you using? Did the shop set up your carb to run 32:1? Alot of shops recommend 40:1 for 250 2t so see what they set up for you. Good luck!

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Did the temps change? rejet your carb then

Did you change brands of premix oil? Rejet your carb then.

Anytime temps or elevation changes or even switching brands of gas will cause jetting changes.

The only other thing I can think of is you are lugging the bike or your inner crank seal went bad and its just sucking in large amounts of gear oil, but more than likely not.

Just for the hell of it go 1 jet size smaller on both the pilot and the main and see if the plugs last a little longer.

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I re-packed my pipe a month ago so no more splooge from the pipe, ive always used Yamalube 2R premix mixed with 91.

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Do you know your jetting numbers? If not you should double check the shops work. It wouldn't be the first time an error has been made by a dealership.

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With the year of the bike, it very well could be a crank seal. I would start with all the free jetting advice on here first though. Get the numbers and make sure its in the ball park. And I would not run the eg plug until you have your jetting figured out. Just run the standerd BR8ES. Running EG's or EIX's can get expensive if your fouling all the time. The EG's do resist fouling better than the standard plug, but you are only masking the problem, thats probably why it went a full day. If jetted correctly, with good main seals and compression, you should be changing your plugs when YOU decide to change (maybe every 6 months?? depending on how often you ride)

Tom

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My rear fender is BLACK and the back of my jersey is speckled with oil spooge....and I don't really foul plugs. I run 32:1 and 40:1 regular pump gas SuperM premix.

The spooge is annoying but I really don't foul plugs so I figure it is just getting lots of lube. :moon: I couldn't find any shots of the spooged fender but this one....

l_4f30e238079e474ead91302690dddf70.jpg

The FMF TCII exhaust is right at the fender. WD40 melts the spooge off the best. :cheers:

Hmmmm I am the last to give jetting advice, but I have fouled 2 plugs in 4 years on my bike. Once was constant stopping and helping little kids and it fouled, never got more than 20ft it was annoying.....the other was a full day of riding in silty conditions and my airfilter was terribly blocked and I was riding up high in the Cascade mountains. Sucky thing on that one is I gave away my spare plug 2 miles before I fouled mine. Doh! ....never again. Had to bum one off a random trail rider that passed me.

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My rear fender is BLACK and the back of my jersey is speckled with oil spooge....and I don't really foul plugs. I run 32:1 and 40:1 regular pump gas SuperM premix.

The spooge is annoying but I really don't foul plugs so I figure it is just getting lots of lube. :moon: I couldn't find any shots of the spooged fender but this one....

l_4f30e238079e474ead91302690dddf70.jpg

The FMF TCII exhaust is right at the fender. WD40 melts the spooge off the best. :cheers:

Hmmmm I am the last to give jetting advice, but I have fouled 2 plugs in 4 years on my bike. Once was constant stopping and helping little kids and it fouled, never got more than 20ft it was annoying.....the other was a full day of riding in silty conditions and my airfilter was terribly blocked and I was riding up high in the Cascade mountains. Sucky thing on that one is I gave away my spare plug 2 miles before I fouled mine. Doh! ....never again. Had to bum one off a random trail rider that passed me.

Yeah you could lean out that jetting a little unless you do alot of open throttle runs. That SuperM isn't helping either since it has a high flashpoint.

For what you are doing probably Spectro or even Castrol 2T oil would do. Low flash points and low ash.

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When I rejetted my bike, it went from nice and snappy to NICE AND SNAPPY. You are loosing power for sure running the motor that rich. And remember, the oil does not cool the engine, it lubricates it. So on hot days it would be possible to overheat your engine. (not that it gets that hot in our neck of the woods.)

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I used to have the same problem with my 96 rm250 and it turned out to be the spark plug boot . It has a resistor inside and when it went bad it was harder to start when hot and would constantly foul plugs . The pluggs would look exactly the same as you are describing . Try a new boot (8-12 bucks) or you can test w/an ohm meter . After replaceing mine it idles, starts easy and have not needed a plug in 2 years (I used to carry 2 brand new ones with me every time i rode) Good luck :moon: I use a br8eg as it way less expensive than what the stock plug 8$ vs 25$ plez sign the petition at http://carnegieforever.org

Edited by still2smokin
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still2smokin i cant seem to find this SPARK PLUG BOOT anywhere online, ive used google and my normal 3 dirtbike sites and cant seem to find them anywhere? do i need to go to my local shop?? any help is appreciated

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I found mine at my local mx shop and I believe it was a nippondenso brand or something like that . It was not model specific just a 90 degree resistor spark plug boot/cap . I hope it works for you ,this problem plaged me for 2+ years .I tried new ignition box, stator and crank seals but it was just a damn spark plug resistor which of course i didnt even know there was one in that boot.

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I believe what you need is a tb05ema (Im going off of memery here....) I have not worked in a bike shop for over 4 years...Im thinking that should be the ngk part number. Should be about 5 bucks.

Tom

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Alright fellas i just ordered that #8 part, 4-7 days ill let ya know if thats the solution, thanks for all the help so far!

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A friend of mine is the original owner of a '97 RM250 and he use to foul plugs all the time. He fixed it by dropping the needle one clip posistion. That is, he went from the stock 3rd slot to the 2nd one down from the top. No more fouling.

I recommend that you try that.

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I fouled a few plugs on my 98 RM250 when I first got it. In an act of 7am desperation, I screwed in a BR8ES from my spares pack for my 81 PE250, and completely forgot about it after it quit fouling out. I believe it lasted about 15 hours, give or take about 15 minutes.

So, trying a different heat range might help. Or it might just have been sheer luck, a crap shoot in the dark that came up 7s.

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