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odds are it will not help may even hurt, you have to be able to get extra air through the engine which means exhaust system and cam may also need to be improved with fuel curve also being increased.
 

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Discussion Starter #3
Already running the RJWC exhaust and dobeck tuner. The rest is why I put this post up. To see what I wasn't thinking of. Cam was one of those
 

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If you bore the throttle body you will also need a larger butterfly plate

DON'T DO IT!

Buy a larger throttle body if you need more airflow
 

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Yea that's what I'm talking about. You didn't actually think someone is stupid enough to drill out a throttle body do you.
 

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Oh my.. why would you want to drill out a throttle body with a hole saw and loose throttle response?





Just kidding lol there really isn't much in the way of polaris ATV performance. I doubt seriously that anyone knows if boring the the throttle body will make more power or not on an xp 1000. It certainly does make more power on yamaha YFZ450s stock carb is 39mm and it's now common to go to 43mm or bigger. The same is also common on other 450cc sport quads. From a little research it is also common for can am guys to swap the bigger 2016 and up throttle body on to older bikes. The throttle body (or carb venturi) seems to be a choke point on many engines. Unfortunately it seems nobody has tried to really make power with these xp engines yet.
 

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Yea that's what I'm talking about. You didn't actually think someone is stupid enough to drill out a throttle body do you.
It a carry over from the 70's when we bored out carburetors to increase the venturi size and air flow. We also experienced a decrease in throttle response coupled with a higher top speed. This has been a goal since increased performance was conceived. 4 barrel carburetors............ two barrels for throttle response and economy and two more barrels for increased acceleration and higher top speed. And all the combinations you can think of; dual quads, tri-power, a separate carb for each cylinder. You can only go as fast as you can afford.

If you have the desire, get a custom manifold, install a second throttle body and work out the programming of the EFI. You might nearly double the output of the engine. Never mind that the engine will break due to the added stress, it's a cost of racing.
 

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The XP twins do have dual throttle bodies from the factory.. unlike the CAN-AMs interestingly.

136168
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That's a link to an ebay posting for a used one. Can confirm on parts diagrams as well. Polaris has changed the part # of the throttle body on the 850s over the years a couple times, as recently as '17 model year for 850s. But I don't know what changes were made. The only visibly obvious change in the parts diagrams is the electronic throttle on '17 and up 1000s.

Latebird, I see you all over this furum and wanted to say thanks for helping so many people out. I'm not being intentionally argumentative, just trying to spread information.

Boring the XP twin throttle bodies would be a bit more involved than some just because of the oval intake runner shape and the injector recession on the intake side of the throttle bodies.
 
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