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Moses Ludel

4WD Mechanix Magazine Tests the Pulstar® PlasmaCore Spark Plugs: Honda XR350R and Honda XR650R Motorcycle Results

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Given the opportunity to test the Pulstar® PlasmaCore spark plugs, we targeted the magazine's Honda XR350R and XR650R motorcycles.  The XR350R is air cooled, the XR650R has liquid cooling.  Both cycles use fixed jet, slide type carburetors.  The XR350R has twin Keihin carburetors, the XR650R uses a single, large Keihin carburetor.
 
We rode the bikes extensively.  The XR350R is OHV permitted for dirt only use, and that testing took place in high desert and mountainous terrain, both dirt roads and single track.  The XR650R with its dual-sport conversion received a full test at both dirt and asphalt riding.  The HD video shares installation details, riding footage and an evaluation of the Pulstar® spark plugs:
 

 

The magazine article is available at: http://www.4wdmechanix.com/Testing-the-Enerpulse-Pulstar-Spark-Plugs.html. We will continue testing and discussing these spark plugs at the magazine and these forums!

 

Here are our test results and findings:

 

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Honda XR650R Motorcycle—This bike is a highway legal dual-sport conversion and ongoing project feature at the magazine. The top-engine is freshly rebuilt to "blueprint" standards, featuring a cylinder head overhaul by L.A. Sleeve Company and a moly-chrome cylinder liner with new piston and rings. We performed all work as a how-to project that became a feature HD instructional video at Vimeo On Demand. The head and upper engine work includes a Hot Cams Stage 1 camshaft. Spark timing and valve timing are "stock" with Honda Power-Up Kit tuning. This popular "uncorking" of the engine's jetting, induction system and exhaust have each been covered in detail at the magazine and the magazine's forums.

This iconic motorcycle model has a large following, as the XR650R is the largest displacement enduro single cylinder bike built by Honda specifically to win the Baja 1000 and other open desert races. The magazine's viewers and forum members have followed the performance gains made with this engine build-up and tuning. The addition of the Enerpulse Pulstar® spark plug provided these noticeable results:

1) Since the rebuild and tuning, the engine has produced superior torque (49 lb-ft estimated) and a high horsepower output (approximately 55 horsepower). Along with the Pulstar® spark plug change, we added a 6.3 gallon fuel tank (5 extra gallons of fuel at approximated 40 pounds net weight gain between the fuel and the large tank) to the motorcycle. Testing the Pulstar® spark plug, performance with the additional weight is slightly better than with the lighter 2.6 gallon factory fuel tank. 40 extra pounds is significant for a dirt enduro motorcycle. When we reinstalled the 2.6 gallon tank for further testing, acceleration and throttle response showed noticeable improvement. Torque increased, and fewer downshifts were necessary under load.

2) A converted dual-sport, highway legal machine, the XR650R is kick start only. Tuning has enabled ready starts with a stock-type NGK spark plug. The Pulstar® spark plug fires the engine with equal ease.

3) Flooding is always a concern on a large displacement single cylinder motorcycle engine. The Pulstar® spark plug strongly resists fuel fouling. The spark plug readily fires through richer mixtures at altitude.

4) This engine has a fixed-jet factory Keihin slide-type carburetor. Altitude sensitivity is always an issue with fixed jets. Larger displacement engines are more susceptible to fuel fouling at higher altitudes. The Pulstar® spark plug, with superior spark output and more complete fuel burn, clearly maximizes performance over a wider range of altitude—even with a fixed jet carburetor. During the road and dirt testing, this motorcycle operated between 4,400 and 7,600 feet elevation with no sign of "rich" mixture spark plug fouling. The fixed carburetor jet setting is for 1,500 and 5,000 feet elevation. Clearly, the Pulstar® spark plugs burn cleaner and more efficiently, producing better power and performance at higher altitudes
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Honda XR350R Motorcycle—This OHV bike is strictly set up for dirt riding. The stock motorcycle was upgraded for desert hare-and-hound scrambles, tuned and jetted for optimal performance at 4,400 feet altitude with the stock factory dual Keihin carburetors. In top condition, with normal compression and peak tuning, the only change was the switch to a Pulstar® spark plug. Our extensive testing in the high desert and mountains spans from 4,000 feet elevation to 6,500 feet elevation. A single cylinder, air cooled engine provides an optimal test bed for combustion and fuel burn comparisons. Pulstar® spark plug test conclusions:

1) Starting is easy whether cold or hot. Starts readily with the choke on. Warms normally as with the stock type NGK spark plug.

2) Throttle response is crisp and noticeably improved. Engine stability under load has improved, requiring less downshifting to compensate for load. (Watch the video.)

3) Again, the most significant gain is less sensitivity to altitude changes with fixed jets in these two carburetors. We operated the motorcycle from 4,000-6,500 feet without adjusting the carburetors or altering the jets. The motorcycle performed flawlessly.

4) This motorcycle has always been miserly on fuel compared to two-stroke engines or larger displacement four-stroke thumpers. Testing revealed a noticeable improvement in fuel efficiency. The motorcycle ran our pre-determined course under load and used less fuel-per-hour than with the stock-type NGK spark plug. This improvement can only be attributed to the Enerpulse Pulstar® spark plug.


We'll continue to evaluate these spark plugs over time.  They offer a significant breakthrough in spark and combustion technology. Enjoy the video!

Moses

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