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Discussion Starter · #1 ·
a friend has a 660 raptor that has a uni filter,stock air box,a yoshimura full exhaust(header and pipe).he got the recommended dynojet kit and followed its directions as far as jet selection and changed the mains and the needles.we are at 1000 feet above see level in pennsylvania.he took it out for the first time today(it has been installed for a couple of weeks just to cold to ride) and he went maybe a mile and the header was cherry red.i know it is way to lean but instead of just pissin in the wind at jet sizes to go to was wondering about some suggestions.in it knor i believe are 146 and a 148 jet.any help would be greatly appreciated.
 

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Someone feel free to correct me if wrong, but you are lean. Stock jetting is 140-145 and your increase to 146-148 is not really that much. Is there poping and backfire? I would try maybe 160-165's to start with depending on your variance in weather. Also you might want to change the pilots as well while you're in there. Have you treid calling the manufacturer and ask what they recommend? It's trial and era my friend, but stick with it and you'll get it. What does your plug look like? Are you running with or without a lid?

Oh! by the way. My CT system glowed like a car cigarette lighter when I first fired it up. But that was normal for my pipe. It stopped after the metals (i guess) got to peak tempatures and cured out. Now it's normal and slammin!!!!! 8)
 

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He's using dynojets, so 146/148 is more like 165/170 in mikuni (stock type) numbers.

Turn the fuel mixture screws out to about 2.5 turns or so and that should richen up the idle a bit for you.

As DONSRYD said, it's not uncommon to see glowing headpipes even with proper jetting.
 

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Ahhh...Young Grasshopper, good to know on the jet difference. I did not realize. I learn somting new ibby-day... :thumbsup:
 

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Discussion Starter · #5 ·
still having issues....would changing the pilot jet help????it is stock now i believe a 22.5....he does not want to run it for fear of blowin' it up.....yoshimura told him that his pipe setup should never glow unless very lean running.....the fuel mixture screw is already turned out 3 turns.any more help would be greatly appreciated.
 

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maybe you should jump to a bigger pilot (one size) and up one size on each of the main jets. did yoshi recommend a size of jet to you?
 

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Discussion Starter · #7 ·
yoshi told him (per the directions) that a jet change would not be needed.....he called dynojet and they told him otherwise....so we already did what dynojet said and are still lean.think he is going to get a pilot jet and try that.we already have the next size up jets that i will install when he gets the pilot.
 

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Discussion Starter · #8 ·
well......we changed the pilot jet to a 25....also put in a dynojet 148 in the left and a 150 in the right carb.....fired it up and within 30 seconds of it running the header was already cherry red......he took it for a short trip and it came back not as red as if the air cooled it somewhat but while sitting still idling it went cherry in 30 seconds again....any ideas guys???????the local shops are worthless they have no clue.....i have a real hard time still thinking it can be lean??????but my buddy is afraid to run it for fear that it is lean and blows up.........any suggestions or ideas would be greatly appreciated.
 

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jump up another size and check the spark plug...
 

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Discussion Starter · #10 ·
go up another pilot jet size or a main jet????i don't think one size main is gonna get it and was told a 27 pilot is to big for just a pipe upgrade???we have the fuel air mixture screw at 3 turns out.do you think i should turn it in to about 2 and see what happens???
 
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