There are many two-cycle snowmobile oils available, and most of them are good products. Some claim to add horsepower and better engine protection. Those claims can’t be proved or disproved without expensive equipment and thousands of hours of run time. But some oil manufacturers claim their lube burns cleaner than others for improved variable exhaust valve performance. That claim is relatively easy to prove, and coincidentally, Legend Performance says its ZX-2SR injection oil’s Clean Burn Technology leaves “virtually no exhaust valve residue.”
With that said, we got a case of ZX-2SR and set out last winter to find out whether the oil would, in fact, keep our 2008 Polaris 600 Dragon demo sled’s exhaust valves cleaner than would the oil recommended by Polaris, its VES Gold synthetic oil.
A Simple Test
All we had to do for this test was drive the sled and perform routine maintenance half-way through the season. The only variable was the driving styles of about a dozen riders over the course of the winter. We controlled oil use by making sure we had plenty of each brand in stock during its “turn” in the oil pump and consistent performance was ensured because the engine’s semi-direct injection fuel system would automatically adjust for weather and conditions.
Our goal was to run each brand of oil for 1,000 miles in our Dragon. The test started with three-tenths of a mile on the sled’s odometer. We ran the Polaris VES Gold oil for the first 1,000 miles. After we cracked the 1,000-mile mark, we removed the exhaust valve assemblies from the engine and gave them a thorough cleaning, a service in which they were in dire need. The guillotines — the part that slides in and out of the cylinder opening to adjust the exhaust port size — were a sticky mess.
They were coated with a layer of greasy, oily crud that would make germophobes run and hide. Most of the gunk washed off fairly easily with carburetor cleaner and a shop towel, but we had to scrub off the carbon buildup with a Scotch-Brite pad. Once the valves were clean, we re-installed them, drained the leftover VES Gold oil from the reservoir and filled it with Legend ZX-2SR oil.
Oil Test: Part II
We hit the trail again for the second half of our test. After we logged another 1,000 miles, we pulled the valves from the engine and gave them an inspection. Frankly, we were surprised at how much cleaner the assemblies were with the Legend oil.
Sure, there were dry carbon deposits built up under a light, oily film, but there wasn’t as much gummy residue on the guillotines that the VES Gold oil left behind. The area underneath the exhaust valve bellows was cleaner, too.
Legend’s ZX-2SR oil kept our exhaust valves cleaner than the oil recommended by Polaris. And we bet it will keep your two-stroke engine’s valves cleaner, too. In addition to cleaner exhaust valves, Legend claims the oil extends engine life and improves throttle response and all-around run quality.
To be honest, we didn’t notice a difference in how the machine ran, but the fact that the valves were considerably cleaner and the engine’s top-end showed normal wear upon teardown made us a believer in the product. At $36 per gallon, it’s less expensive than some other aftermarket and OEM injection oils.
Cold-weather pour: 2/2
Legend Performance Inc.
Traverse City, Mich.