Monday, February 22, 2010

Royal Enfield oil cooler: do you need it?

The web site Indian Cars Bikes does a road test of two AVL engined Royal Enfield motorcycles, promising "real world data" on the benefits of the oil cooler fitted to one of the bikes.

"Cooler oil naturally equates to a cooler, happier and more importantly a longer lasting engine which does not lose its consistency/power-torque output at higher temperatures," the authors write.

The test was carried out at noon in Pune, India. The outdoor temperature was 76 degrees Fahrenheit. The two bikes were run up to 40 mph and their temperatures taken. The article does not say how long the motors ran or how far the motorcycles traveled or over what terrain.

The motorcycles were not identical. The one with the oil cooler had a K&N filter and Goldstar-style muffler and had been rejetted to suit. It was filled with synthetic oil.

Oil cooler is installed neatly.

The motorcycle without the oil cooler was stock, except for rejetting, presumably just to correct the typically too-lean factory settings. It was filled with regular motor oil.

The authors of the article spent several paragraphs justifying the test results.

Neither the synthetic oil nor the more free-flowing systems of the modified motorcycle would cause it to run naturally cooler, they argue. The authors acknowledge that such changes are often touted as contributing to cooler running, but they discount any such benefit.

They did note that the Royal Enfield with the oil cooler had been parked in the sun prior to the test, while the stock bike was in shade. This could not have been very important, but the fact that they bother to mention it is interesting.

Perhaps they felt that things were indeed otherwise stacked in favor of the modified motorcycle.

"So, there, we have the comprehensive test results of the oil cooler, boosting engine cooling by almost 24 per cent," they conclude.

No doubt the oil cooler did its job and presumably produced measurable cooling. Probably that would be an advantage or a safeguard on a motorcycle run hard. But it would take a far more rigorous test (to destruction, presumably) to prove it.

I would sooner use the cheaper and time proven technique to cool off my Royal Enfield: just slow down.


  1. Anonymous2/25/2011

    how do you have mearsured the temperature & according to theory oil cold is required in main bearing crank bearing thus cold oil in Rockers make any difference in acctual temperature of engine oil it is mainly reguired in main bearing as impoorted bikes have please reply me on my e- mial id

  2. Hi... Well oil tempreture at that time I checked on thermal gun. Under various conditions and time. Due to existing setup of rocker pipe there was no other choice but fitting the cooler in between banjo line yes the difference in overall tempreture was good. My next cooler was going to be an advance but unfortunately I dropped the idea to go ahead since UCE engine came. I tried on UCE but it got failed.


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