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Discussion Starter · #1 · (Edited)
i have a 01 raptor 660r uni filter, lid off the box, lexx slip on quiet core removed. had from the factory 135l 140r mains. i had the quiet core in with factory jets and it was really rich. then took out the quiet core and put the larger mains in brand new plug went for a spin and plug is white... could it still be this lean or am i missing something idk.. thanks for the insight. let me also add im at 4500 feet elev...
 

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Master of the Electron
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With lid off, you need at least 155L/160R Mikuni jets... the numbers you are stating sound more like DJ jets, if those are Mikuni numbers you are WAY too lean -

Stock jets 'from the factory' are Mikuni 140L/145R - not what you had.
 

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With lid off, you need at least 155L/160R Mikuni jets... the numbers you are stating sound more like DJ jets, if those are Mikuni numbers you are WAY too lean -

Stock jets 'from the factory' are Mikuni 140L/145R - not what you had.
I believe he said "then took out the quiet core and put the larger mains in" but never said what size mains he installed? I have not seen a Raptor with anything other than 140-145 stock main jets so something strange is going on.

Removing the airbox lid requires quite a bit more fuel than stock jetting, so just as quad said 155-160 is a good starting point.
A description of what the bike is doing at idle and various throttle positions will help in getting you closer to the proper jetting.
Good luck.
 

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I believe he said "then took out the quiet core and put the larger mains in" but never said what size mains he installed? I have not seen a Raptor with anything other than 140-145 stock main jets so something strange is going on.

Removing the airbox lid requires quite a bit more fuel than stock jetting, so just as quad said 155-160 is a good starting point.
A description of what the bike is doing at idle and various throttle positions will help in getting you closer to the proper jetting.
Good luck.
It doesnt necessarily mean you are using more fuel when you change the properties of the stock air box, you are changing the vacuum level in the carbs by changing the airbox and to compensate you must install larger jets to compensate for the decreased vacuum to get the proper amount of fuel..............
 

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It doesnt necessarily mean you are using more fuel when you change the properties of the stock air box, you are changing the vacuum level in the carbs by changing the airbox and to compensate you must install larger jets to compensate for the decreased vacuum to get the proper amount of fuel..............
I simplified my understanding by thinking more available O2 would require more available fuel....but I see how vacuum is the determining factor.

Here's a brain teaser. If I were running 150-155 jets at 500 feet and removed the airbox lid --at the same time I moved my bike to an elevation of 4000 feet --would that require more jet? Seems the vacuum would be the same but the available O2 would be less...anyone?
 

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I simplified my understanding by thinking more available O2 would require more available fuel....but I see how vacuum is the determining factor.

Here's a brain teaser. If I were running 150-155 jets at 500 feet and removed the airbox lid --at the same time I moved my bike to an elevation of 4000 feet --would that require more jet? Seems the vacuum would be the same but the available O2 would be less...anyone?
Oxygen level is usually around 21 %..............just the higher elevation you go, the less dense the air is............
 

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It doesnt necessarily mean you are using more fuel when you change the properties of the stock air box, you are changing the vacuum level in the carbs by changing the airbox and to compensate you must install larger jets to compensate for the decreased vacuum to get the proper amount of fuel..............

Exactly - with less restriction to air flow, there is less of a vacuum difference across the carb throat, so there is less 'sucking' on the jets... bigger jets returns you to the proper amount of fuel with the lower vacuum.

However, running at 5000 feet causes the bike to run richer so you need to go down about 10-15 or so in jet size.
 

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Discussion Starter · #9 ·
successs

ok so here it goes testing it all day and waiting at rockymountain atv for 2 damn hours for jets lol they lost the order 3 times on the conveyer belt... anyways 160l 165r with 25 pilots 2 turns out and it is a completely different machine. no hanging idle nothing and with stock gearing it pulls up in second on me 240 lbs i love it sorry for all the problems dumb questions etc its amazing though
 

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Discussion Starter · #10 ·
i lied looking at the plug today it still looked lean so i went to 165l 170 r and its perfect color and runs really good but i bought this bike from my dads friend and he has not done anything to the bike since he bought it from the factory sohere is the questions why the 135l 140r jets and a 12t front sprocket was on it...
 

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Seemingly a bit rich, even for sea level, but every engine is different... if it works, it works!
 

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stoopid cerbaraughters
 

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Discussion Starter · #13 ·
thats what i thought too but the spark plug reads good. here is a question if i have the wrong heat range for the spark plug it will read wrong right what heat range should i run in this.?
 

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Discussion Starter · #14 ·
ok...

looking at the plug i went to 165 170 and it runs even better now how the heck but the plug is still reading lean the heat range is black on the outside ring the resistor is white and where it sparks to idk what its called is burnt white... what the heck is going on man and as it is set up now it beats my uncles banshee with the big 3 so idk man should i not pay attention to the plug or what?
 

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looking at the plug i went to 165 170 and it runs even better now how the heck but the plug is still reading lean the heat range is black on the outside ring the resistor is white and where it sparks to idk what its called is burnt white... what the heck is going on man and as it is set up now it beats my uncles banshee with the big 3 so idk man should i not pay attention to the plug or what?
Please show a picture of the plug.
How long have you driven the bike to determine your conclusion that the plug looks lean?
How much of the center electrode is silver, if you are using either an EIX or an EV plug
 

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Here's a brain teaser. If I were running 150-155 jets at 500 feet and removed the airbox lid --at the same time I moved my bike to an elevation of 4000 feet --would that require more jet? Seems the vacuum would be the same but the available O2 would be less...anyone?[/QUOTE]

Oxygen level is usually around 21 %..............just the higher elevation you go, the less dense the air is............
Yes O2 is always at 21% regardless, unless we travel to another planet, but density changes so the amount of O2 at 4000 feet is much less than 500 feet.
 

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Master of the Electron
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Here's a brain teaser. If I were running 150-155 jets at 500 feet and removed the airbox lid --at the same time I moved my bike to an elevation of 4000 feet --would that require more jet? Seems the vacuum would be the same but the available O2 would be less...anyone?


RE the teaser - If I recall , a jet change of -5 per thousand feet elevation is typical, and an increase of around 15-20 is necessary when removing the lid. So, 4000ft = -20, lid off = +15 to 20. It would be a close call.
 

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I don't believe in plug checks - they require specific procedures to make any sense, when done properly they only tell you about mixture at WOT (which we are at only a small percentage of the time) and I can't verify that an online pic has been generated using the proper procedures.

How does the engine RUN? If you are concerned, bracket each of the circuits - richen until you notice a change, lean until you notice a change... you want to be right in the middle between those points, IMO.
 
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