Clean Air Made Easy!

There's a first time for everything. Remember the first time you removed and cleaned your air filter on your new CRF450 (or CRF250 for that matter)? Here's a memory that will haunt you every time you think about doing it again! We get emails on a regular basis asking if there's an easier way to remove and install the air filter. Our replies have always sounded like instructions that only a contortionist could follow. Bottom line, there's no easier way...or is there?

Our friends at Twin Air sent us their NEW PowerFlow Kit that's designed to accomplish three things:

1. Provide a better air box seal with an aluminum inner sealing ring
2. Improve intake performance by increasing airflow
3. Make removing and replace the filter quicker and easier

The first thing you notice about the Twin Air system is how simple it appears. The kit includes an aluminum sealing ring, a billet aluminum filter cage, and an air filter. That's it! Comparing the stock setup to the Twin Air setup is like comparing Frankenstein to JLo.

Start with the stock filter, what a hideous thing to look upon. If the multiple flat glued panels weren't ugly enough there's a rubber seal sewn to the base with a blue piece of foam glued on top. All of this has to be sweet talked onto the backfire screen. No simple task! Once completed all you have to do is stuff it into a place that was designed for something much smaller. This "place" is otherwise known as the CRF450R air box. Even if you manage to get the filter assembly in the air box are you ever really sure it's seated correctly? No, we didn't think so.

What about the performance of the stock air box you ask? Just look at that backfire screen and ask yourself if you were air would you resist going through that screen? Exactly.

So, what about the Twin Air New PowerFlow system? Well, it's a work of art. Your first thought after seeing this will be, "too bad no one will ever see this but me." The quality and attention to detail is perfect. Even the air filter itself is perfect. Its contoured and molded foam reduces the size significantly helping the filter assembly even easier to remove and install.

Speaking of the filter it's a dual-stage filter. The outer layer is a course foam designed to remove the large particles. The inner foam is finer, and also backfire resistant, and filters out the small stuff. This dual-stage technology allows for increased air flow without compromising filtration.

The filter cage was designed assure a quick and easy positive seal during installation. You can see from the picture the inner sealing ring has three spars that not only provide strength but also align with the three center prongs of the filter cage assembly. This virtually eliminates the possibility of installing the filter incorrectly. As a bonus it makes it quicker too!

Let's review. Quicker and easier to remove and installl. Increased airflow for better intake performance. Better sealing at the air box and the inner sealing ring. What more could you ask for? Oh, you'd like Honda to deliver this system on stock CRF's? Since that's not going to happen, ever, our recommendation is to install the Twin Air's New PowerFlow Kit now. You'll be glad you did every time you clean your air filter!

Installation Notes

1. Remove the seat (10mm socket), silencer (10mm socket), and fuel tank band
2. Remove the top sub-frame bolts (10mm socket) and loosen the bottom sub-frame bolts (12mm socket)
3. Loosen the air box boot ring from the carburetor with a Phillips screw driver
4. Remove breather tube at top of air box
5. If you have any frame guards or rear master cylinder guards that would prevent the sub-frame from rotating down remove them
6. Carefully rotate the sub-frame downward. You'll have to help the air box boot slide off the carb.
7. Put a clean rag or paper towel in the air boot and carb to prevent errant debris from entering
8. Remove the six 8mm nuts that hold the air box plate (8mm socket and 8mm open end wrench for the two that are covered)
9. Remove the stock inner sealing ring. You'll have to work at getting the sealer broken free from the air box Use a standard screwdriver to help and be patient.
10. With the inner ring removed, clean the surface of any remaining sealer or debris
11. Apply a strong bead of Permatex High-Temp RTV Silicone Gasket Maker to the air box side of the Twin Air aluminum inner sealing ring. This will assure an airtight seal and prevent any unfiltered air from entering your carb.
12. Install the Twin Air aluminum inner sealing ring and tighten the provided allen head screws and nuts.
13. Install the oiled PowerFlow filter on the Twin Air cage. Align the filter correctly to the shape of the cage. Install the wing nut prior to installing filter assembly.
14. Install the filter/cage assembly. You'll notice an "alignment tab" on the filter and a corresponding area on the inner ring (see photo). Align this tab to the flat area of the inner sealing ring. This will get you very close, if not exactly, where the cage will engage properly on the ring.
15. Tighten the wing nut securely.
16. Reverse instructions to restore sub-frame, air box, and seat.
17. That's it...now get out there and dirty up that filter!

Additional Notes:

• If you use the Twin Air Air Box Cover the supplied wing nut is too short as it was designed to be used with the stock setup. Use the same wing nut used for the new filter cage.
• The 10mm bolt for the top of the sub-frame should be torqued at 22 ft.- lbs.
• The 12mm bolt at the bottom of the sub-frame should be torqued to 36 ft-lbs.

CRF's Only Staff Review - November 2004
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