Power expectations and Jetting - Yamaha Raptor Forum
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post #1 of 3 (permalink) Old 12-20-2016, 11:52 PM Thread Starter
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Question Power expectations and Jetting

I just came home with a 2011 Raptor 125 with only 12 hours on it for my daughter. It has a FMF powercore 4 slip on and nothing else, airbox lid on. I took it out for a little test ride and am worried. Her younger sister has a TRX90 and as it sits now the 90 is much more powerful. The Raptor won't even pull all the way through third gear with me on it and just bogs in 4th and 5th. It seems to have no torque at all, especially in the middle of the powerband. It idles rough, with the rpms raising and lowering randomly. I haven't had much time to troubleshoot, but I am also admittedly not very knowledgeable. I adjusted the air screw to calm down the idle as much as I could, and I checked the plug for air/fuel ratio. It seems lean to me, and with the exhaust and no other mods that would make sense.

First I want to get my expectations in order. This quad should be at least marginally faster than a trx90 right? I read some reviews that all said it was a very torquey motor for a mini, but I am not getting that impression. Am I expecting too much?

Second, where should I begin to troubleshoot the idle and mid band power issue? Move the needle up? does anyone know of a tutorial or video showing how to do it? I am mechanically inclined, I just have no experience with carbs at all.

Does anyone know the stock jet sizes and have a recommended changes?
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post #2 of 3 (permalink) Old 12-21-2016, 02:35 AM
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You're prolly lean, you should bump up your jetting. Start with your main jets, bump a few sizes till it runs better, then play with the needle position. Your carb info will be in your manual.

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post #3 of 3 (permalink) Old 12-22-2016, 11:45 AM Thread Starter
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I didn't get the manual with the bike. I ordered the HMF jet kit which comes with a few main sizes and a new pilot. I'll figure it out. Anyone know of a video or even pictures of the easiest way to pull the carb out and do this without tearing the whole quad down? It doesn't seem like there is any space in there to take it out especially on the air side.
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