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metalm0

450 wont even try to fire

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Ok I know this would be technically the wrong section since its a yfz450 rather than a yz450f but the question is on a cousins quad so didnt want to register for a new forum just for one querstion. Anyways, the bike will crank and crank and crank and not even a sign of trying to fire. He never rides the bike so I figured I would take it out for a spin and this happened. Plenty of gas, maybe bad gas from sitting for so long? No spark? Didnt think this ever happened to 4 strokes with spark plug problems, just wanted to see what you all could throw out there. Thanks.

Josh

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How long did it sit?...Todays gas goes bad faster than it used to. Take the plug out and replace it (most likely fuel fouled by now with all the cranking over) Drain the float bowl and tank, fill with fresh fuel charge the battery and give it a try......

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My WR450F won't fire if gas has sat in it too long. +1 on changing the gas and charging the battery (that seems to help as well). I use an irridium plug; CR8EIX. That seems to help the bike fire and feels like it runs better.

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Since the Quad engine/electricals are nearly identical to the WR, I'm going to move this over there. The advice you've gotten so far is good.

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Ok I will have to run and grab a plug and drain all the fluids. I will give that a go tomorrow night. Thanks a lot.

Josh

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Couple ideas:

1 - I don't want to sound like a jerk, but is the fuel petcock on? I drained a battery and kicked myself into a frenzy one time before I realized the fuel petcock was off :doh:

2 - My WR 250F used to have a terrible time starting if it sat for a week or so. I found out if I tip it on it's side to get fresh fuel in there, it would fire immediately.

I agree with the ideas above about the plugs, and would suggest you check the float bowl for gum - If it sat long, it may need to be cleaned.

Good luck

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Ya fuel was on. He literally hasnt ridden the bike for a few months so I am guessing bad gas. I am gonna buy a new plug and drain the carb and tank tonight. Now with these 4 stroke carbs, whats the best way to drain them? Thanks.

Josh

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Ya fuel was on. He literally hasnt ridden the bike for a few months so I am guessing bad gas. I am gonna buy a new plug and drain the carb and tank tonight. Now with these 4 stroke carbs, whats the best way to drain them? Thanks.

Josh

Pull the fuel hose, drain the tank.

Put the fuel hose back, fill with fresh gas.

On the float bowl, open the 3mm drain screw (it's pretty obvious) and flush a couple of bowls worth of gas into a tin.

Sometimes, just draining the float bowl a bit with old gas refilling the carb will get the engine started.

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Haha this is going to sound like a newb but I swear there was gas in there when I was trying to get it to fire. I pulled the hose from the petcock to drain the tankl, not a drop of gas. I threw some gas in there and first touch of the start button she fired. Battery is having trouble keeping charge though through the night.

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Heheh, isn't that always the way things go? :doh:

After 2 years, I had to replace the battery on my WR250F. If the vehicle sits with the battery connected, the battery sulphates and then it's a goner.

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Haha ya thats for sure. Another thing I am not sure this is like how it is on the wr's, but I am used to 2 stroke, but do you actually have to take the tank off to change the plug? doesnt seem like too much room in there, I dont have to do it, just was curious.

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Haha ya thats for sure. Another thing I am not sure this is like how it is on the wr's, but I am used to 2 stroke, but do you actually have to take the tank off to change the plug? doesnt seem like too much room in there, I dont have to do it, just was curious.

I take it off. Just a few bolts and a clip. Takes 5 mins. But tbqh, I don't think that I've ever just changed the spark plug.

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My father always told me...GAS, SPARK, AIR! In that order...something that simple is frustrating, isn't it!

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