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2 stroke -plug keeps getting fouled


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I recently switched from a 4T 250 to a 2T 125. 2T are totally new to me but I'm getting use to the difference in the way the bikes handle. Although, I keep fouling the plugs. I do only trail riding. The bike is an 07 CR125 with a brand new top end. totally mint. The guys at the shop gave me some advice on keeping it rev'd out while riding b/c that's how 2T like to be treated. But even in doing that i somehow fouled the plug yesterday. I tipped the bike early in the ride trying to cross a gnarly river bed. But it was able to start right up after- but 10-15 min later it bogged and i had to change the plug. Trying to figure out if it was the tip over or my riding that fouled the plug?

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a properly jetted bike wont foul plugs...the easiest thing to do is raise the clip up one notch on the needle. see if that works B4 buying a bunch of jets...if its bogging right of the bottom, lean out the air screw a 1/4 turn at a time.

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Tip over could have done it, but unlikely. I've fell down many times(🤣), and never had a fouled plug issue from it

I'd say it's jetted too rich. A properly jetted bike can be lugged around all day and never foul a plug. When used for MX, richer jetting is the rule as they are screamed on the throttle stop all the time. Try to transfere that to woods riding, with more low and mid range usage, and it'll be jetted too rich, thus fouling plugs.

Jet it correctly, and it will seldom, to never, foul a plug.👍

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also it will foul when it is cold, they cool down really fast, blank off a radiator with duct tape, go out for a spin see what heppens, i have had a radiator blocked of for 3 months now, when it warms up a bit ill remove

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also it will foul when it is cold, they cool down really fast, blank off a radiator with duct tape, go out for a spin see what heppens, i have had a radiator blocked of for 3 months now, when it warms up a bit ill remove

Outside temperature also affects jetting. Colder temps, and the increased oxygen density, will in fact, make the bike run leaner, thus less prone to fouling plugs.

Blocking off radiators only promotes overheating and engine damage. Will have no real consequence at all on plug fouling.

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the radiators are capable of keeping the engine temp steady in 35degrees +

A enigine looses horse power when it gets hot because the air isn't as dense

Trust me my bike is jetted perfectly, in summer full radiators, and in winter i block one off, because if i dont it fouls plugs.

This advise has to me from the Husqvarna dealer who works close to the husqy team.

If the bike doesnt get to the right temp, the oil will not burn properly, thus fouling plugs (aprillia rs250 are really bad for this)

If you are on the trail there is no way in winter you can keep the motor singing to keep it at peak temp, 2 stroke cool much faster than 4 strokes

you dont have to follow this advise, this is just my 2pence worth, which in the bigger picture means Jack sh*t

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What pre-mix are you using? A high flash point MX/racing pre-mix like Klotz R50 or a castor oil will not burn off all the way when trail ridden, especially if it's cold out. Any of the modern synthetics with a flash point of 250* or less are what you want for trail riding. Also, while the bike is fairly new, it could be a clutch side main seal going bad, which would cause tranny oil to get sucked into the engine. I've seen that happen before, an obvious sign is if the bike puts out a lot of smoke, even on the pipe. But as other have said before, get it jetted properly first.

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All these guys are right but compaired to a 4 stroke a 2 stroke is a plug eating machine. Never ride without a spare.

This is the best advise some one can give you, saying that my dont foul plug's, post a picture of your spark plug end so we can see the burn marks??

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All these guys are right but compaired to a 4 stroke a 2 stroke is a plug eating machine. Never ride without a spare.

I've fouled a plug 2 times in my KTM and I've got 700+ hours on it. Both happened in weather that was below freezing. Having said that, I sure do carry a spare with me.

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I've fouled a plug 2 times in my KTM and I've got 700+ hours on it. Both happened in weather that was below freezing. Having said that, I sure do carry a spare with me.

when its freezing i blank off a radiator to keep engine at temp

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