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Boyesen Rad Valve Reviews

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Product Information

  • Price Range $159.95 ~ $272.95 Shop Now
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Product Details


   6 of 6 members found this review helpful 6 / 6 members

Smooth, crisp revs & evenly distributed power. Riding a 2018 300xcw I have little need to improve the low end of the bike from its mostly-stock engine. This Boyesen Rad Valve not only increased my usable power down low, but changed the bike’s delivery characteristics of that power.

I moved from Texas, where I purchased the bike, to Colorado, consistently riding between 7,000-10,000ft. Given the altitude change I had to rejet. I rejetted for current conditions. I spent a week and every relevant jet size, both stock and aftermarket jet kits, to get the perfect jetting combination. I arrived at a perfect combination on circuit at a time and that combo is still in the bike today.  

In the Rad Valve’s instructions, it says your bike may need to be rejetted once installing the Rad Valve. What I think they meant was “if your bike is not already jetted correctly, this product will expose your bad jetting” lol. No seriously, bolted it right up and it cleaned my entire rev range and the power comes on so smooth. No bog, no hesitation, nada. It was immediately noticeable and now will lug well below idle cleanly. I did not have to change any jets, still no spooge at the end of a ride, and the spark plus nice and golden. I would highly recommend this product.

Quick Install Tip: Use the supplied hardware from Boyesen. Because this one-piece unit replaces the stock boot as well as the reed cage, the stock hardware is too long and will crack your cylinder if torqued all the way down.

The Boyesen Difference:

Maintain airflow velocity through the valve and redirect to intake charge for even intake distribution

Pull a gear higher on hills; instant acceleration makes passing effortless

·         The machining, fit & finish are top notch

·         Stock intake is two pieces; the Rad Valve is one solid piece. One less place for an air leak

·         Model-Specific Reed Petal Tensioning

·         Multi-Stage Reed Timing

·         All hardware and gaskets supplied

·         Increased fuel economy

All in all, the rad valve will be something I look to add to every bike in the future. Especially as some stock reed cages do not have the quality control these Boyesen units do. My stock reeds had huge gaps at the top and the bottom. Boyesen’s? Tight, exact fit.  👍

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Hans Schmid

   2 of 2 members found this review helpful 2 / 2 members

Being that I spent months building my 2007 YZ250 into the ultimate "do everything" machine, I was still on the hunt for added performance to compliment my motor. When Boyesen asked if I would like to test their Rad Valve product, I felt that this would be a excellent addition. I have had great results with their reeds in my stock cage, so I was excited to test the complete Boyesen Rad Valve system. With a freshly "woods" ported motor in my YZ, I felt that I couldn't lose!

Product Overview

Crafted out of aluminum, the Boyesen Rad Valve is the only air intake system available with aerodynamic internal surfacing. What does that mean? It means that there are no hard edges to interrupt the flow of air and fuel into your motorcycle. This becomes quite apparent when comparing the Boyesen Rad Valve against the stock unit. The intake track is very straight and smooth. Add in the fact that each unit is specifically tailored to your motorcycle, it instills even more confidence that you are getting optimal performance. This is not a "one size fits all" product. As for the reeds, they use their own proprietary weave formula that is tested and optimized for each make/model/year machine and to compliment your Rad Valve. You really can see the type of quality and testing that Boyesen puts into their products.

One thing to add is this is a straight bolt-on performance mod. There is no assembling or cutting. Just remove your stock system and replace it with the Boyesen system. Boyesen does supply instructions, a gasket, and five 8mm bolts. For my model year, I welcomed the 8mm bolts over the stock Allen head bolts due to them always being filled with dirt and more prone to stripping. The instructions are quite basic and are set as a general guide that is easy to follow. Some jetting information is also offered. If you have any questions regarding the product or tuning advice, Boyesen techs are quick phone call away.


I had a lot of options as to where I was going to put the Boyesen Rad Valve through its paces. I chose my practice loop because I know it so well, I thought that it would add to my testing consistency. A series of short hill climbs with no runs, a few open stretches, lots of logs, a few rock ledges, and a few miles of stop and go switchbacks make for a great starting point.

Before my first run, I had leaned the bike out one size on the pilot and main jets, but left the needle in the same clip position. After a short warm up, away I went. It was noticeable right away that I needed to lean the bike out a bit more, but interestingly enough, even though the motor was running rich, it wasn't blubbery or loading-up. It just wasn't as crisp as it could be. The motor felt somewhat like the bike did with the stock reed cage.Throttle response was similar, but the bike did seem to gain a bit of RPMs. This is welcomed as I run the stock exhaust which is known for not being the best pipe for high RPM. It was still a successful ride; never once did the bike let me down, but I knew that I could do better.

The next time I went out, I dropped another size on the main and pilot and lowered the needle one clip. Wow, did the bike come alive! Throttle response was excellent right off idle and over-rev felt great. But, what really impressed me was how more linear and more smooth the motor had become. Dare I say F.I. smooth? The low to mid and mid to top-end transition felt excellent. Man, for me especially, this really tied my motor together. The stock unit seemed to create a "dip" in the mid-range when transitioning from the low-end, but the Boyesen Rad Valve seemed to really fill that gap. Two areas on my practice loop that I have to pay close attention to are the short hill climbs and the logs. Any hesitation or hiccup while going over a log can result in me going over the bars. The added smoothness and throttle response of the Rad Valve makes for getting the front end over logs so much easier. Regarding the hill climbs, if you hit them wrong or a gear too high, prepare for a lot of clutch work. With a nice clean pull, the Boyesen unit made for a bit easier time. I wont say that you could hit them a gear high, but the motor didn't seem to work quite as hard when you stabbed the clutch. I'm very impressed with what the Boyesen Rad Valve did to my motor.

Pros 👍

  • Looks trick.
  • No assembly required and easy to install.
  • Simple and easy instructions.
  • Great performance mod that is cheaper than a pipe and less prone to damage.

Cons :thumbsdn:

  • Jetting (might take you a few tries).


After really thinking about the product and testing it, I have come to appreciate what the Boyesen Rad Valve is. Many riders spend thousands on performance mods for their bikes, but overlook some of the simplest things that offer the biggest gains. Being a simple, bolt-on product, designed and built specifically for your motorcycle, I don't think that you can go wrong with this performance mod. The bike gained performance everywhere. From down low to up top, the bike pulled cleaner and stronger than with the stock unit. Yes, the jetting is something that will need to be played with, but jetting needs to be done when adding many bolt-on products. Comparing the Boyesen Rad Valve to the stocker (well, it really isn't a fair comparison), hands down, the Boyesen unit is better. If you own a two stroke and you are in need of some performance gains, I highly recommend not to over look the Boyesen Rad Valve!

You can get one at Boyesen.com for $179.95.

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   0 of 1 member found this review helpful 0 / 1 member

I picked up the boyesen dual stage reeds. Install them 2 days ago. Now it runs like a Yamaha it465! front-wheel wheel comes off the ground without having to try! Powerband is smooth and consistent. I am super impressed! Granted the old Reeds were worn out. But no matter. These cost less than Factory or even used ones.

 this kid is only the reeds. You must get your own gasket.




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I love it, incredible throttle response 

Pulls hard 

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More powa

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