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Discussion Starter · #1 ·
This will probably be one of the strangest questions but I need to know. I have been researching the Big 3 upgrades and have pretty much decided I want to go with a Pro Design intake, PCV and the DMC Force 4 Duals.

My concern/question is with this setup will my Raptor handle being riden at idle and just above up to about 2500 rpm in first gear?

Now to explain why I ask. My son got his Polaris Outlaw 50 this past Christmas and riding in the back yard has lost its appeal (and the grass should start growing soon).
So, today we went out for the second time to the other ATV park close to home and I noticed I never hardly get above 2500rpm. I figure this will be the range of our riding for at least another year maybe two.

I may get to go out with the other "Big Boys" occassionally and that is when I want the increased performance for!
 

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If you're in such a low gear at such a low rpm all of the time I would suggest changing your gear ratio so you can turn a few more rpms, it will also drop your idle speed which may make the task of following the little fella around easier on your brakes. A smaller front sprocket will also take a bit of the load off the engine.

As for performance, well at 2500 rpm you aren't really looking for any. You'll want to make sure you have a good tune, whether it be done on the dyno, a base map (you may need to modify it) or a map you get from one of the members here. I cite this because in the hunt for hp sometimes the a/f ratio at lower rpms can get over looked and might be a little too rich or a little too lean. The former will cause carbon buildup at these rpms, while the latter will cause it to run hot or even overheat. But properly tuned I see no reason why you shouldn't be able to run these modifications without any negative impact on your experience or performance.
 

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Discussion Starter · #3 ·
If you're in such a low gear at such a low rpm all of the time I would suggest changing your gear ratio so you can turn a few more rpms, it will also drop your idle speed which may make the task of following the little fella around easier on your brakes. A smaller front sprocket will also take a bit of the load off the engine.

As for performance, well at 2500 rpm you aren't really looking for any. You'll want to make sure you have a good tune, whether it be done on the dyno, a base map (you may need to modify it) or a map you get from one of the members here. I cite this because in the hunt for hp sometimes the a/f ratio at lower rpms can get over looked and might be a little too rich or a little too lean. The former will cause carbon buildup at these rpms, while the latter will cause it to run hot or even overheat. But properly tuned I see no reason why you shouldn't be able to run these modifications without any negative impact on your experience or performance.
Good to hear! I don't have to ride the brakes any and I am usually leading because I want to know what the terrain is like that he has to negotiate and if needed I stop him until I get across and then come back on foot to guide him and catch him if needed (Large ruts, steep hills, off camber tracks, off-camber across small ravines, etc).

I was thinking maybe a larger rear sprocket might be good, just didn't think about reducing the front one. Mainly because I like to have as many teeth available and engaged as possible for the few times I do hammer on it.

I probably don't even need the Big 3 mods but you all know how it is, men always want more!
My BD is in a few months so I was thinking that might be a good time to ask for the Big 3.
 

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A big 3 bike isn't going to overtax a 13 tooth front sprocket, there's no need to worry about how many teeth are engaged as you'll have plenty regardless of the setup. I would have suggested more teeth on the rear sprocket except for a few drawbacks; larger rear sprockets decrease ground clearance (whether itself or by requiring the skid plate to be shimmed) and they cost 3-5 times more money than a front sprocket. That said, if you can live with these drawbacks then increasing teeth on the rear gives you more control over the ratio as one tooth in the rear is only about 1/3rd of a tooth up front. The lower gearing will make negotiating those obstacles at low speeds easier on the clutch (as you won't need to slip it or engage it as much) and the mechanical advantage will be useful as well.
 

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Discussion Starter · #5 · (Edited)
A big 3 bike isn't going to overtax a 13 tooth front sprocket, there's no need to worry about how many teeth are engaged as you'll have plenty regardless of the setup. I would have suggested more teeth on the rear sprocket except for a few drawbacks; larger rear sprockets decrease ground clearance (whether itself or by requiring the skid plate to be shimmed) and they cost 3-5 times more money than a front sprocket. That said, if you can live with these drawbacks then increasing teeth on the rear gives you more control over the ratio as one tooth in the rear is only about 1/3rd of a tooth up front. The lower gearing will make negotiating those obstacles at low speeds easier on the clutch (as you won't need to slip it or engage it as much) and the mechanical advantage will be useful as well.
Good point about the cheaper front. As for the Ground clearance, the GYTR skid is already far enough away for a larger sprocket, possibly too far IMO.
 

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Discussion Starter · #6 ·
Would these be considered good brands? Both are Steel.

PBI Countershaft Sprockets
Sunstar Rear Steel Sprocket
 

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Would these be considered good brands? Both are Steel.

PBI Countershaft Sprockets
Sunstar Rear Steel Sprocket
They're fine. For what your doing the Tusk RMATV Primary Drive one at $9 would be my choice. Once your son gains confidence and his speed increases you'll be taking it off anyway. No need to spend extra in my books.
 

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Discussion Starter · #8 ·
They're fine. For what your doing the Tusk RMATV Primary Drive one at $9 would be my choice. Once your son gains confidence and his speed increases you'll be taking it off anyway. No need to spend extra in my books.
I agree with you. TQS has the two I listed for 17 and 31, which I thought was good. Where did you find that one at for $9? I tried a quick search and didn't find it.
 

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www.rockymountainatv.com they have name brands too, but the primary drive is a generic alternative that will work ok, but will wear out fast if you don't have a good chain, or it isn't adjusted right. just keep it adjusted and you'll be good for a season or 2, which is normal for cheap sprockets, good ones "can" last up to 3 or 4 seasons, maybe more if you NEVER ride. :lol: i had a 13t on my big 3, and it helped. but i also had 22" rears, so it was close to stock ratio. but it will also help your get up and go when your going fast, but you will lose some top end speed which i wouldn't worry about from your description of riding terrain.
 

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Discussion Starter · #10 ·
I put the Moose 13T front and Sunstar 40T rear sprockets on last night. Interesting that the gear ratio only went from 2.71 to 3.08.

I was kind of surprised how easy and quick it went, seems I always encounter some unforseen snafu.
Any way, I took it out and around the yard a little and it doesn't feel much slower but I'm sure it will be better on the quad though. It will sure raise the
front easier!

Front Rear Ratio
15 36 2.40
15 38 2.53
15 40 2.67
14 38 2.71
14 40 2.86
13 38 2.92
13 40 3.08
13 42 3.23
 
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