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Discussion Starter · #1 ·
i have a 03 660 with, a 686 bore, with a duncan racing hp4 kit, with a mega cycle drag cam. my raptor pulls hard up untel 4th gear and it seams to lose a little power, and when a hit fifth it falls on its face. with the x-14 cam it should pull like a train on the top. i still have the stock carbs, and ignition. me and my bro were thinking that the carbs couldnt keep up with the high reving cams.
 

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Very few recreational bikes are running that cam, it's just way too aggressive for rideability.

My guess is that no only can't your carbs keep up but your porting (or a lack there of) is a contributing factor as well.

Gearing is going to make a big deal here too, with that cam if you're too tall you wont have the torque to pull 5th.
 

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Discussion Starter · #4 ·
well my jets are 175 and 170, think i should bump them up a size

my engine has been ported by duncan

duncan thought the problem was the carbs, and maybe the clutch. they also told me that i should switch to there fatboy 4 exhaust, i am running ct exhaust. they said that i would get more power with theres because their hp4 kit they did for me was set up for that exhaust. would switching exhaust make that big of a difference
 

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It would make a little difference...you'd lose about 2 hp going to the Duncan.

Clutches are common, I've broken a couple. May want to look into a wiseco or GYTR/Hinson clutch basket.

I'd definately say you're too lean, I was running that jetting at 500' asl with just a pipe, open airbox/filter kit and a stage 1 hotcam all on an OEM head.
 
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