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Discussion Starter · #1 ·
Hey guys so I got a 03 660 raptor and I got the spark problem all fixed thanks to you guys but now I’m having another problem the bike idles perfect shifts nice and I give it throttle and it runs fine till about quarter throttle then acts like it’s hitting a rev limiter or something and backfires out the exhaust and spits and sputter where should I even start on this ?
 

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Assuming your jetting isn't wildly off, sounds like a classic parking brake issue. QM and the others will have more info on how to fix it.
+2, parking brake or reverse sensor issue. For parking brake, join the 2 terminals that go to it so it's a closed connection. For reverse sensor, now this is from memory, if you unplug the connector from the sensor it should display reverse, so needs grounded. Might be the other way around, but can't honestly remember. If it is the other way around just unplug and see if that solves your issue.

Mike
 

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Master of the Electron
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PB limiter is right above idle, reverse limiter is near 1/4 throttle. My bet is on reverse. Can I guess your reverse light doesn't work?
 

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Discussion Starter · #5 ·
Ok so it was the jets I’m pretty sure main was at 175 and the second carb was at 145 and the pilot was at 57 this is all from the old owner so I bought brand new carbs from Yamaha dealer near me just to cancel the carbs as a problem in general but it is having the same problem but doesn’t backfire as much just bogs at about half throttle now but does have a k and n air filter and white brothers exhaust would that cause it to have any problems
 

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Discussion Starter · #6 ·
And I’m assuming the barking break sensor is the one that is in the clutch lever with the parking break lever 😂 and if it is then it has already been removed
 

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Yes will need jetted for the K&N and Exhaust, I'll look up what I had in my 660 when I had mine. Also try lifting the needles slightly, try 1 notch at a time. Both the switches for clutch and PB should be in the clutch perch as this is where the PB is too. Wouldn't surprise me if they are gone, most are from my experience
 

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Ok well that would make sense I’m just not sure on the jetting I will need
So let's talk about this carb you got from the dealer...is it an OEM mikuni or a Chinese knockoff? Seems kinda weird to get a "new" 660 carb from a dealer, never heard of that happening at least in the last 10 years. If they sold you a Chinese knockoff without disclosing it as non OEM for more than $50 you should take it back for a refund.

As far as jetting for your mods, if your airbox lid and snorkel are not modified, you'll want mains 145 left and 150 right. Needles in center position and 22.5 pilots at 2.5 turns out.

If your airbox is modified in any way, you'll want mains 160\165, Dynojet needles 1 notch rich of center (very important for needles to be DJ brand), and pilots size 25 about 2.5 turns out. Without the Dj needles, you'll always be too lean for most of the throttle positions except maybe WOT.

These suggestions are for OEM carbs, you may have significantly different jetting with a Chinese carb, and it's very possible you'll never get it to run right.
 

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Hi I have a similar problem I’m at 1080 elevation and Im running a full hmf exhaust with stock air box, what should I have my carbs tune, what size Jets and what placement on the needles, I’m having trouble
 

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Hi I have a similar problem I’m at 1080 elevation and Im running a full hmf exhaust with stock air box, what should I have my carbs tune, what size Jets and what placement on the needles, I’m having trouble
For your mods with an OEM carb, mains 145L\150R. OEM needles in center position. Pilots 22.5 and fuel screws about 2.5 turns out.
For a Chinese carb, all bets are off and good luck to you.
 
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