IIRC the intervals for HD use to be every 2500 or 3K miles.

My bikes get changed between that mark. My cars go 5K miles. Why? My cars are not air cooled engines.

 

I use Amsoil and change it out every 5K, but I really don't notice the engine running any cooler.

If you are changing out the oil every 2500 miles, there's no need to use synthetic oil...JMHO.

 

Naw, not for longer useage, just does so much better at the temps the Air cooled HD motor runs at...

Cars/ water cooled, runs at <180* bout any oil will work..
HD runs anywhere from 190- 260, pends on what yr, and work done. So the syn just holds up better over the long run...

 

This is the reason that I run Mobil 1 synthetic.

 

For the added protection synthetic oil gives your engine,it's worth the extra cost. You spend good money to own a Harley,why not use the best?

 

I've been using Mobil 1 car oil in my aluminum engines since '89 and wouldn't think of changing. I still use straight weight HD oil in the iron beasts however. Synthetic leaks out too quickly.

 

The use of synthetic oil has NO advantage in a non-high performance engine running in moderate climates. period.

If you think a harley engine is high performance you are sorely mistaken.

The only two practical advantages a synthetic oil has is that it can withstand higher tempertures and it flows better at lower temperatures. So if you live in the desert and you find yourself constantly stuck in traffic where your engine heats up then you might consider synthetic, or if you ride in the winter in sub-freezing temperatures then there is an advantage there as well.

The only other benefit it has is maybe you can go longer between oil changes, but, sythetic oil will wear out, become acidic, and eventually become saturated with particulates just like regular oil. So you have to carefully monitor the state of your oil if you're planning to leave it in for extended periods of time. This practice will void your warranty.

Folks, I am not making this up and it's not a matter of opinion. These are true facts I've posted here and you may research them yourself. Google "motor oil myths and facts". Don't read the page from mobil 1. They are naturally biased and are interested in selling you their product.

oh, and ps, this is the biggest myth of all "my engine runs cooler when I use synthetic". BS. If your engine were to run cooler that would mean the difference in temperature is due to extra friction when you use regular oil. If that was the case an engine running normal oil would last about 10 minutes then blow up due to the friction. It's balony. There is virtually NO difference in PERFORMANCE when you run synthetic vs non.

 

1] withstand higher temperatures 2] flow better in colder temperatures 3] can go longer between oil changes. well zeus33 those are 3 good reasons to use synthetic oil over dino oil. And the reason they can go longer between changes is the additive package that is put in the better oils can deal with the acids that build up in oil. The detergents in say mobil 1 or Amsoil are in alot higher amounts then Harleys own hd360. You can go to bitog's site and compare them for yourself. new oil analysis and used oil analysis. And as long as you have a filter that works the particles in the oil will be kept there. Yes synthetic oils will need to be changed, but not as often.

 

1] 99.9% of the bikes don't need the protection from high temperature. Under normal operating conditions your oil won't heat past the point where it breaks down. Like I said, high performance engines need the high performance oil, high perfomance engines run hot. Synthetic will not make your lawnmower last any longer, nor will it benefit your harley (unless you have a racing model)
2] sub-freezing temperatures! Impossible to ride in, no application in the case of motorcycles.
3] will void your warranty if you go past your interval. Change your filter with a good quality k&n (not the harley junk) and you should be good to go for 5000 miles.

No there is no need to put synthetic in a harley. Just like you don't need it in your lawn mower.

 

Are there actually any good arguments in favor of normal (non-synthetic) oil?

To me, the best argument in favor of synthetic is, I'm not giving money to the oil producing countries when I buy it.