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Kuryakyn Hyper-Charger

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Now here is an interesting item. It is possibly one of the most popular after market product for sale, and yet could be the cause of a lot of the problems I have been hearing about.

Let's start with something you might not have noticed. One of the most attractive things about the Hyper-Charger are those cute little butterflies that flutter open and closed when you work the throttle. It's so cool, just like the blowers on the top fuel funny cars... except for one thing, the Hyper-Charger butterflies operate off manifold vacuum and the top fuelers are operated mechanically by the throttle linkage.



At idle and normal cruising speeds, the main air intake is through the open butterflies, but when you accelerate, opening the carburetor or throttle body butterfly - the manifold vacuum drops causing the Hyper-Charger's butterflies to close. Now the main air intake is shut off by the closed butterflies so there has to be another air intake area, and you will see a slot at the bottom rear of theHyper-Charger body for this purpose.



Kuryakyn claims that installing this air cleaner kit will improve performance and horsepower and that is true... under the right conditions. The reason it improves performance is because it utilizes a K&N free-flowing style filter, the same as you will find in the Screaming Eagle air cleaner kit and many others, even S&S is using the K&N style filter now. What the company does not tell you is that it will produce much better results on the dyno than on the highway. On the dyno it works great, but the dyno won't reproduce that 80mph wind forced into this air cleaner and out the rear like you get on the highway.



Because of the way the air travels into the front and out the rear of the Hyper-Charger, instead of forcing air into the carburetor, it actually pulls or "siphons" air (and fuel) out. As a result, you get what has been described as a "dead spot" or lack of power at highway speeds, not to mention the fuel breaks down the oil in your air filter hampering it's usefulness and the fuel mixed with air filter oil tends to deposit itself all over the right side of your bike when you go on long rides and then when you stop it all drips down on the cam cover, your foot, that cigarette butt you just dropped, and so on.
 
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re: Küryakyn Hyper-Charger

A Hypercharger was the 1st "accessory" I bought for my '92 Dyna. It didn't take long for the "chattering" butterflies to irritate me, so I disconnected the vac. and they stay open.
No one ever noticed the butterflies opening and closing anyhow. I have never had a problem with gas/oil mist blowing out on the bike. I have tried taping over the bottom to see if stopping the siphoning had any effect, but didn't notice any. I have had my bike on 4 dynos over the years and two of the operators claimed the Hypercharger was not among best HP producers. I still like the look of the Hypercharger, but have to admit they are overpriced. And like most of Kuryakyn's products, are made of cast pot metal, which has a tendancy to bubble and pit under the chrome.
 
re: Küryakyn Hyper-Charger

I installed the hypercharger on my '94 FLSTC and along with the K&N filter has proved to be an effctive AC. I don't see how it siphons anything out of the carb because the butterflys close not open with more throttle. Along with looking cool I have only good things to say about the hypercharger
 
re: Küryakyn Hyper-Charger

Never did any measurments to see if it's linier to the throttle position, but when crusing at 65 to 70 mph the butterflys are about 80% to 85% closed. When I spoke with a Kuryakin rep many years ago this is how the hypercharger is supposed to work, with most of the air geting to the carb thur the bottom of the fixture. While it looks like it is a "Ram" air induction, and I'm sure that was the manufacturer intent, it doesn't function that way. Does this make sense or am I just rambling?
 
re: Küryakyn Hyper-Charger

If the manufacture wanted most of the air to come in through the bottom then it makes complete sense. Now I understand. I was thinking the opposite, more like NHRA.

Have to admit, they do look Cool!
 
re: Küryakyn Hyper-Charger

IMO, it would make more sense if it were sealed at the bottom and the butterflies were to open with throttle.

The claims to more HP by the manufacturer (if any) were basically the result of the taller K&N filter in this unit and not derived from the design of the unit.
 
re: Küryakyn Hyper-Charger

IMO, it would make more sense if it were sealed at the bottom and the butterflies were to open with throttle.

I agree but maybe they don't want big bugs or birds to get sucked in at 75 MPH? They take down JumboJets..:D
 
re: Küryakyn Hyper-Charger

When I first instaled mine that is exactly how I thought it was supposed to work. Went so far as to take the vacuum attachment apart to see if I could reverse the pull. When I spoke to the manuf. rep he told me that it is suppose to look like something from an NHRA dragster, but max air flow comes from negitive pressure inside the carb and not from ramming air into the carb throat.
 
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