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riding with no fuel screw?


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last time I rode my bike was not starting when hot.

so before todays ride I turned the idle and the fuel screw out 1/4 turn to see if that would fix it and go from there.

25km later I decide to check the fuel screw and turn it again... hmm, either its not there any more, or I really am a retard like BBA says and I cant see it.

so I get off my bike and what do I see? nothing!! my damn aftermarket screw rattled itself out of the carb! and I had been riding it like this!! I didnt notice any performance losses in the bike, so I continued to ride all day and put another 40 or or so km without the fuel screw. bike ran fine but it would idle high sometimes.

so I am wondering... did I hurt anything by riding it in about 60km (2 engine hours) of trails with no fuel screw in my carb?

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It's very unlikely you hurt the engine. Although the idle circuit is part of the fuel mixture throughout the rpm range, once you're on the metering rod and main jet, it's rich enough to survive unless you were at WOT and hitting the rev limiter all day.

Did you have the spring, washer and oring on the new mixture screw?

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It's very unlikely you hurt the engine. Although the idle circuit is part of the fuel mixture throughout the rpm range, once you're on the metering rod and main jet, it's rich enough to survive unless you were at WOT and hitting the rev limiter all day.

Did you have the spring, washer and oring on the new mixture screw?

no I wasnt WOT or rev limiter all day.. but there was a few times on a hill climb or down the gravel road where id have her screaming. I was putting in the trees/tight single track and it got pretty hot for some reason, was up to 105C on the vapor computer and its usually never above 100C so I thought it might have something to do with the fuel screw, but I doubt it.

yes I had the spring, and o-ring on... I dont recall there being a washer on there, but im positive I installed it correctly, its idiot proof. I think it was just bad luck + the fact that I unscrewed it about 1/4-1/2 turn before I started riding. that probably left it hanging on by 1 thead and it rattled itself out.

and TBH, I probably would have never noticed the fuel screw even missing other than it idiling high sometimes🤣

but guess ill just have to guy buy another one for like 45$ 👍

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yeah, that happened to me once too but it started running funny so I stopped and the needle was sitting right under the carb. I think the spring was gone so it would not stay in anymore. I bought a new one and a spare. Carry the spare in my tool pouch just in case. I think RockymountainMC has one that is like $11 or $12.

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Sounds like you were way too far out with the fuel screw to begin with. You shouldn't be any more than 3 turns out, at which the spring should still have enough tension on the screw to keep it from backing out. If the bike was running alright without it, then you have the wrong pilot jet in it. A new extended fuel screw is only $17-$25 depending on what brand you get.

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Sounds like you were way too far out with the fuel screw to begin with. You shouldn't be any more than 3 turns out, at which the spring should still have enough tension on the screw to keep it from backing out. If the bike was running alright without it, then you have the wrong pilot jet in it. A new extended fuel screw is only $17-$25 depending on what brand you get.

yes you are completely right, I thought about it all day and you summed it up exactly.

but I dont get what you mean about the pilot jet... which jet is that? I have the JD jet kit and am 99% sure it is jetted accordingly for my bike, temp, altitude, etc..

it has a 68 or so jet in it, I have no idea of anything else but could tell ya by looking at my JD jet kit 👍

thanks.

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yes you are completely right, I thought about it all day and you summed it up exactly.

but I dont get what you mean about the pilot jet... which jet is that? I have the JD jet kit and am 99% sure it is jetted accordingly for my bike, temp, altitude, etc..

it has a 68 or so jet in it, I have no idea of anything else but could tell ya by looking at my JD jet kit 👍

thanks.

Your carb has multiple jets in it, each one metering fuel for a different range of throttle. The pilot jet is what meters fuel from closed throttle to about 1/4 throttle. Since this range is the fussiest range, the fuel screw is added to further adjust the fuel metering in this throttle range. The fuel screw basically blocks off part of the pilot jet, making it seem like there is a smaller jet in there, but not enough to be like having thenext size smaller jet. Generally if you take out the fuel screw then the carb will suck air through the hole it left, making the bike run lean below 1/4 throttle. If your bike ran fine with no fuel screw in, then it would seem to me like you have too large of a pilot jet in.

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so how do I check the pilot jet then? all I know is the main jet and needle 👍

thanks.

I'm sorry, thats entertaining. You question my knowlege:thumbsup:

haha wow Santan9, you are the true character. Thats a fact. All im going to say is. WoW.

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I'm sorry, thats entertaining. You question my knowlege:thumbsup:

haha wow Santan9, you are the true character. Thats a fact. All im going to say is. WoW.

yeah this is coming from a guy who says "duh" and "I could be wrong" in the same sentence 👍 and I didnt question your knowledge, but you can keep telling yourself that if it makes you feel better. I said you are an as*hole, to which several people agreed and you jumped from arguing with me to arguing with them, AND THEN goes and edits his original post and tries to lie about it even though someone quoted the original, unedited first post. goes to show the kind of person you are. now youre ruining my thread.

at least I got the balls to admit when im wrong and dont know the answer, you on the other hand have yourself convinced that youre prefect and know everything🤣 you just go ahead and keep following my posts talking smack, its all youre good for.

you can access the pilot jet thru the drain plug hole on the float bowl...it is off to the side of the main jet. it has a flathead/slot.

thanks for the info, Ive only been in my carb once or twice to change main jet + needle, so I dont know everything about it like mxn4life does. I will go tinker around with it after supper when theres some room in the shop and report back.

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I'm sorry, thats entertaining. You question my knowlege:thumbsup:

haha wow Santan9, you are the true character. Thats a fact. All im going to say is. WoW.

Are we 5?

The question has already been answered, but yes, the pilot jet is right next to the main jet, it sits up a bit higher in the carb though.

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