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Discussion Starter #1 (Edited)
I pulled this posting out of a dauntingly long 18 page forum thread which had this information somewhere in the middle. I wanted to move it to the How-to area for easier reference.

original thread
Ok I was bored so I'll type some... Let's start with the top & work our way down but first start with a clean machine, if your bike is dirty wash it before you start including under the engine cover.

The air the engine breathes enters through the slotted inlet on top of the engine cover on 04-05-06-07 models and uses a short snorkel between it and the air box located directly behind the shifter. The stock snorkel has an inside diameter of 1.625 inches and simply is not enough to fill the lungs easily of a big 660 cc cylinder and is comparable to us trying to breathe through a straw while running. The cure is to simply replace this snorkel with a larger one, sounds simple enough but I have only found one source to buy this item rather than fabricate your own and I found it in ebay from the user wwlknsn. He calls his product the "Roostin' Rhino RAIS Power Tube" and sells them for $30 delivered. I do not know this person other than chatting of forums and get nothing from this recommendation, I am only informing you of a source for the item. This RAIS has an impressive 2.25 inch diameter and almost doubles the amount of air available to the engine, it comes out to be 191% larger than the stock snorkel on paper.
Installing it is easy, remove the stock snorkel and simply press the RAIS into place, it comes with very good and specific instructions. It has a couple of marks to align and your finished. I chose to drill 2 small holes through the flange and install 2 screws to ensure it would not move but it's not necessary. If you feel the same then do the same.
Now that the Rhino is breathing easier we move along to the next component, the air filter. The stock air filter is a very good unit and will serve you well with regular maintenance. If you feel like upgrading to a SB filter, Uni or K&N etc. now is a good time to do it as we will be tuning the carburetor shortly and a different filter will have an effect on this.

Another (better) option is using a "hard mount" air filter. This was intended for the guys that like to run without the air box lid and breathe hot dirty air, but the lid is what holds the stock filter in place so the solution for them was to add a mount inside the air box to allow the use of a "clamp on" air filter. I ran the stock style K&N filter for well over a year and had good luck with it. But during a service I noticed the filter was not sealing up as well as I prefer so I went to the hard mount style, but I still use the lid for the air box for several reasons. In short my opinion for a great intake set-up is the RAIS on a stock air box with a hard mount filter inside.


Next in line, the carburetor. Carburetor work is rather easy but intimidates many, but there are few moving parts to screw up so I say give it a try yourself. If you screw it up it should be easily fixed. First find and loosen the single #2 Phillips screw located on the bottom of the carburetor, it is directly above the rubber tube attached to the bottom of the float bowl, this will drain most of the fuel from the carburetor. Remove the 2 electrical wires connected to it that operate the "heater" and note their location for re-assembly. Next loosen the clamps securing it on the front to the manifold and in the rear securing it to the soft rubber tube leading to the air-box, then pull it out of the manifold and away from the engine, turn it slightly and out of air box tube as well.
The first thing to do to the carburetor is adjust the height of the jet needle. Remove the two #2 Phillips screws holding the top cover on, then the spring beneath it and finally the slide and diaphragm. All you need to do is simply reverse the thick & thin washers on the jet needle (thicker on the bottom side) this is a simple effective way to get some more fuel flowing and have a better air / fuel ratio for performance. Pull the plastic plug holding it into place with pliers, swap the washers and reassemble taking care not to loose the small spring. Also be careful replacing the spring and cover not to damage the diaphragm. Your done with the top of the carburetor.

Now turn it over carefully as the throttle cable will still be attached along with a vent line etc. if you find it necessary to remove any additional items and do this on a work bench simply note the location of the items you remove to free the carburetor taking note of everything for re-assembly. Locate the plug that is covering the low speed mixture screw, it is on the side closest to the engine. Drill a small hole about 5/32 will be fine in this plug. If you have left handed bits use them, either way drill lightly as the plug is not very thick and drills easily with a sharp bit. Try to avoid the drill plunging thru and hitting the screw that is beneath it, that's why I urge caution & left handed bits. (counter rotating bits) If you plunge through drilling clockwise it is easy to catch the screw with the bit and over tighten it in an instant which could damage the carburetor. With the hole drilled into the plug, screw a self tapping screw into it, drywall screw whatever you have then pull the plug out with pliers. The mixture screw is beneath the plug, turn it in just until lightly it's seated then back it out at least 2 full turns, or 720 degrees. You may need to turn it further after you reassemble and test. (I ended up a 4 turns on mine)
Next there are 4 screws securing the float bowl to the bottom of the carburetor, break the screws loose with a #2 Phillips screwdriver, this can be difficult for some people so make sure your using a #2 tip screwdriver that is not worn or rounded to make it as easy as possible, a tiny pair of pliers are useful for this if you have anything like that. After you remove the screws carefully remove the float bowl taking care not to get anything inside etc. Remove the jet that is in the center that should be stamped with a #145 on 05-06-07 models or #150 for 04's, replace it with a #155 for most areas. If you live at very high elevations you may be better off with a #150 or #152.5 if your unsure ask a professional in your area as nothing works perfectly at all elevations. Lastly I have had good results with replacing the stock size #40 low speed or pilot jet that is right next to the main with a #45, again elevation varies with this as well. That completes the changes and reinstall the float bowl, tighten the screws and reinstall everything in the reverse order you removed them. Be sure to re-attach the 2 wires for the heater and close the drain valve on the bottom of the carburetor. Jet selection is critical and nothing else is quite as critical to the performance of the engine so if you are not confident in your abilities take the carburetor or the entire machine to a professional to have this done.



Now it's time to fire it up and see how you did. The Rhino uses a vacuum fuel pump, the engine must be spinning to pump fuel. Since the carburetor is empty the engine will need to spin several times before the pump delivers enough fuel to the carburetor to start, do not use the throttle when starting. Opening the throttle reduces the amount of vacuum and it will simply require more engine cranking to get it restarted. After the engine starts allow it to warm up fully then set the idle speed if needed. If you do not have a way of measuring the fuel mixture you will simply need to adjust it "old school style with a combination of test riding and plug reading.

For those in a similar situation, go to Lowes or Home Depot and get a screw extraction tool along with two 5/32" drill bits (good to have a spare if you break one...like I did). Also pick up 4, 4mm x 12mm long machine screws with a 10mm hex head. After extracting the screws, re-jet the carburetor like Pro Wrench instructed, and re-assemble the bowl to the carburetor using the 4mm machine screws purchased.

Circled A/F is the plug which must be removed.


Chart showing jet size comparison to Dynojet's number system. I felt it might be relevant to those swapping jets around.


 

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I pulled this posting out of a dauntingly long 18 page forum thread which had this information somewhere in the middle. I wanted to move it to the How-to area for easier reference.
Thanks. This should be helpful to many. Do you still have the location of the original thread? It might be helpful to have a link posted within this newly minted thread such that someone curious or looking for related Q&A's, regarding this transplanted write-up, can easily find it.
 

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I should have read your info before I started on cleaning my carb. I have a 07 660 rhino. I drilled out the cap for the A/F screw, not knowing for sure which was the correct one, I also drilled out the bigger brass cap right behind it and removed,OOPS, don't think I should have done that one, After reading your post, you don't say anything about that one, wonder what my options are, looks like it inserts a certain way, am I going to need to buy a new plug, or is there a way to reinstall this one. **normally I read about info before working on carb, but i didn't on this.
Thanks for any input for my screw up!!

Randy
 

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I should have read your info before I started on cleaning my carb. I have a 07 660 rhino. I drilled out the cap for the A/F screw, not knowing for sure which was the correct one, I also drilled out the bigger brass cap right behind it and removed,OOPS, don't think I should have done that one, After reading your post, you don't say anything about that one, wonder what my options are, looks like it inserts a certain way, am I going to need to buy a new plug, or is there a way to reinstall this one. **normally I read about info before working on carb, but i didn't on this.
Thanks for any input for my screw up!!

Randy
Ha ha. I started doing the same thing and was like "how thick is this thing?" Then I looked up and saw the a/f screw already showing. Luckily I didn't drill all the way thru the thick brass plug. Lol
 
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