Cycle News Staff | June 2, 2017
The 2017 Honda CRF450R/RX ProMoto Billet spark-arrestor end-cap assemblies come with a removable nozzle, a spark-arrestor screen, and all required mounting hardware. They are made from machined 6061 aluminum right here in the U.S. ProMoto Billet end caps are an economical way to convert your stock mufflers into a U.S.F.S.-approved spark-arrested mufflers.
When the spark-arrestor screens are not required, like riding at the MX track, they are very simple to remove. The removable portion of the end cap (nozzle) is machined out of solid 6061 aluminum and anodized with a protective finish. If cutting down on the noise output of your bike is important, ProMoto Billet offers the Silent Insert. It reduces the exhaust note by 3-5 decibels and is very easy to install into the ProMoto Billet end cap.
List Price:
Spark Arrestor End Cap Assembly (set of 2) $259.95
Silent Turn-Downs (set of two) $79.95
Promotobillet.com
Standout Feature:
Makes it so you don’t have to purchase a whole new muffler (or two) if you’re in need of a spark arrestor for you bike. This saves you money!
Rider Analysis:
We found that the installing the ProMoto Billent end caps to our Honda CRF450RX to be and easy but time consuming, but that’s no fault of ProMoto; it’s just that the stock end caps are difficult to remove, and difficult to remove without damaging them. Once the stock mufflers are ready for the new end caps, they bolt right up.
The ProMoto Billet end caps, even with the spark-arrestor screens installed, mimic the power output of the stock end caps. The outlet diameter of the ProMoto Billet end cap nozzle is fairly large and lets the exhaust flow freely, which is great for riders not wanting a spark arrestor to hamper stock performance. This free-flow design means the noise output is equal to stock, even with the spark arrestors installed.
On the track we were very happy with the performance, but, off-road on tight single track the CRF450RX is still loud, ultra throttle responsive, and a handful in technical terrain. We installed ProMoto Billet Silent turn-downs in an effort to mellow out the off-idle response and lower the noise output. Install is only a 2-minute job and the Silent turn-downs work well to quiet the CRF450RX while softening the initial power hit. With the Silent turn-downs, the CRF450RX doesn’t feel so motocross and hyper. The Silent turn-downs also helped reduce the flame-out tendency at lower rpms.
Overall we really like the ProMoto Billet end caps. They allow three different configurations for our CRF450RX and allow us to legally (and a little more quietly) enjoy riding areas we wouldn’t be able to access with stock mufflers, all for a reasonable price.CN