This was a very popular topic on the old forum so I figured I would bring it back up.

Would like to get your opinion on running synthetic oil vs standard motor oil and other petrolium based lubes in your bike like the tranny and primary.

Would especially love to here from some of the mechanics we have here.

Ok, I'll be first...

I have been running syn lube in my RoadKing (and my last RoadKing) for 6 years and over 75,000 miles on the first one and 20,000 and still going on my current.

I have not noticed any difference in performace, but what I do notice is that when it comes time to change it, the old comes out much cleaner with a lot less metal shavings.  I can only guess that this is due to a lot less friction between parts.

I know this is a Harley tech category, but I'm going to throw my two cents in.

In the racing world just about everyone has gone to syn lube. I know dino has been around for a long time and has done a good job for all of us over the years, but the times are changin'. The difference is with dino oil, it can only be so slippery because of the properties it comes with out of the ground. With synthetic lubricant, they continually improve it to do nothing be be slippery.

At the track we care a lot about how hot our engines get, and with syn, they run much cooler because of the reduced friction. The reduced friction also cuts down on the wear and tear of internal parts saving us lots of time and money if we can go longer between rebuilds.

Bottom line is oil has seen its day, we can make it better, stronger, faster...we have the technology!

Here's some info on lubricants. I've been selling oils & petroleum products for over 25 years. With todays engines, especially air cooled, their running much hotter due to the unleaded gas we burn in them. With out the lead, theres less lubricant in the gasoline which makes the engine run at higher temps. In the state of Penna. we have two different kinds of gasoline. Summer gas and winter gas. The difference between them is the summer gas is oxyginated so it will evaporate easier or quicker in more humid weather. We also seem to lose a little mpg's this time of year. This is all due to the clean air act which was signed in 1992.

Anyways. with the engines running hotter. petroleum based oils start to burn at approx 340 degrees. Once this happens, all the additives and lubricating properties cease to exist and you need to change the oil asap. If your using a synthetic, ie, Syn 3. or Mobile 1, these will take temps. over 500 degrees. For what they cost, $10 per qt., it's well worth it in an air cooled engine.

I have seen Harley engines stuck in traffic and in parades run upto 340 degrees when the outside temps. are over 80 degrees.  And oil cooler work if your moving in the wind at speeds of 40 mph or more, so if ya live in a big city with lots of lights, don't bother...By the way Syn. fluids will run 10 degrees cooler in your engine that petroleun based oils.

I'm a self trained motorcycle mechanic for the most part, so I don't know all the technical specs of the synthetic lubes or the old dino oil, but I do know I wouldn't run anything other then synthetic in my bikes. Like a couple people already said, you just don't see as much gunk and metal shavings when you change the oil, and in my book that's a good thing.