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Discussion Starter · #1 ·
My uncle just bought a 660 we wnet over all the wireing and cleaned the carbs but I can't get it to hold an idle. If i adjust it up to idle it will idle but if i wack the throttle it takes a few seconds for rpm to drop bake down. I had it idleing for about 5 mins and it just revd up realy high. and i will idle up and down a little bit just sitting but if i shut it off n let it cool and try to start it it wnt start without throtle like 1/2 way open. 55/50 mains 22.5 pilots needles on 2nd clip up K&N filter no lid and a yoshi slip on
 

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I am unique
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My uncle just bought a 660 we wnet over all the wireing and cleaned the carbs but I can't get it to hold an idle. If i adjust it up to idle it will idle but if i wack the throttle it takes a few seconds for rpm to drop bake down. I had it idleing for about 5 mins and it just revd up realy high. and i will idle up and down a little bit just sitting but if i shut it off n let it cool and try to start it it wnt start without throtle like 1/2 way open. 55/50 mains 22.5 pilots needles on 2nd clip up K&N filter no lid and a yoshi slip on
First, you need #25 pilots, and aftermarket needles with no lid and you could need mains as high as 160s, You may also need to clean the carbs internally................
 

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Master of the Electron
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1st, those mains must be 150 in the left and 155 in the right. Regardless, they are too small. With the lid off of the airbox, you need more like 155L / 160R with a slip on. You do need 25 pilots, as Willy said, with the lid off also.

But, as Willy also said, it is very likely that your carbs are plugging up internally, especially the pilot jets. Any area in the carb that is wetted with fuel from the float bowl will get plugged up with varnish from evaporating gas.

The carbs need to be removed and cleaned, inside the float chamber, down to the individual jet - rodding out with copper strands (stolen from speaker wire) if necessary and sprayed out with carb cleaner to get the tiny passages in the pilot jets completely cleaned out, along with all the other passages.

To avoid this problem in the future, turn the fuel petcock off and let the bike idle till it dies whenever it's going to sit for more than a day or two.
 

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Discussion Starter · #4 ·
I cleaned the jets and passages with torch tip cleaner. I had the whole carb apart and cleaned it with the tip cleaners carb cleaner then blew it out with compressed air. If i put the lid on will it make a difference and whats the difference between aftermarket and stock needles. I put the jets outa my vitos jet kit in his quad they look the same as the stock jets do they have a different taper where the needle seats? and whats with the goofy jet sizes for DJ I have some of those
 

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Discussion Starter · #5 ·
I think I have 160s in my raptor its a 686 with an 11:1 cp piston n a fmf power bomb with whit bros e series, no lid with a pro designs foam filter. you said 160s in my uncles with just a slip on n no lid. wheres should i be
 

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Master of the Electron
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Where we told you. Doesn't matter what compression or displacement is... only how much air flow from intake to output of the carb and exhaust flow has been modified.
 

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Discussion Starter · #7 ·
So on my quad with a full exhaust and foam filter should be jetted the same as his with just a slip on and no lid
 

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You know this is not an exact science, a bit of experementation is necessary, the numbers that are given are approximate, aka a good starting point. once you modify something, it will require you to try different jets until you find what works best with your combo and altitude.

Good luck and love your Raptor!!! Because it will kick your but if you mistreat her!! LOL
 

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Master of the Electron
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Slip on will generally be jetted a bit leaner than full exhaust - the largest change in jetting (relative to stock) is due to opening up the airbox.

Usually, with open airbox and slip on, I suggest 155L/160R, with open airbox and full exhaust I suggest 160L/165R or larger. Difference between foam and K&N style is small, but may move you up or down one jet size. As Click said above, it does require iteration unless you luckily hit it right-on the first time.
 
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