I have an 05 deluxe with 13K miles. It has had the HD 360 oil used in it since new as far as I can tell by talking with the past owner.Changed every 4-5K miles. with no problems what so ever.I am considering changing the oil now to a synthetic oil. With the track record on the non synthetic oil would you still make the switch ? Mobil 1 V 20/50 and Mobil 1 trans oil ? I know I want to change the trans over. The motor I am just not quite sure. Why mess with a good thing so far. Are there any negatives. Thanks

 

I'm not going to repeat what characteristics make synthetic oils better than dinosaur oils but, I consider the synthetic oils like Mobil 1, Redline and AMSoil to be better oils. You can read for a couple of days on here and on other websites about the differences. Opinions vary concerning the value of synthetic oils, the length of time between changes and everything else involved with oil in our air-cooled v-twins. Myopinion is Mobil 1 in my motorcycle engine, Redline in my transmission and any good 10W40 oil in the primary.

 

Dito to what Tbone said. You can check out that Amsoil white paper. It's got a bunch of tests on it. I used it and picked Lucas Syn 20/50. It scored good in the important test, and it as most, synthetics have a viscosity index of over 100 (Lucas VI after a 10,000 mile trip still held a VI of 148).

Lucas Syn 20-50 in the crank, Filter change @ 3750, and change oil & Filter at 7500.
Lucas Syn in the primary, change at 7500
Bel-Ray 85-140 in the Tranny. Change at 5K.

 

Scott
Is the bel ray 85/140 a syn oil also. I was at the dealer the other day and the parts guy was recomending that same oil.

 

I know the benefitts of the fully synthetic over the standard dino oil. I guess my question is A bike with 13K miles on it and having ran the dino oil since new. Any downside of switching to a full synthetic at this time ?

 

No, absolutely not. On older bikes, pre twinkie, people would go to syn. and start to have leaks. That was sometimes attributed to the syn being more "penetrating" but was more likely due to the detergent content dissolving varnish that was keeping old, dried up gaskets tight.

With the tendency for these things to run hotter because of lean maps etc, using an oil that withstands heat better and even reduces operating temps a bit makes lots of sense. Sticking to what was used before makes none to me.

JMHO,
EZ

 

There will be no problems at 13K on an 05 Harley switching to synthetic oil. Too many buy into this myth about oil leaks and or problems making a switch from dino oils to synthetic. An 05 is new enough to have modern seals and Harley recommended synthetic in 05.

Dino oil and synthetics are compatible after changing from one to another with a new oil filter and again 13K is really no big deal at all.

As you allready know, synthetics are just a better oil overall for an air cooled motor. I would say go for it...

Take Care,
Bill G

 

I would switch it to synthetic. The seals in an 05 should not be effected. I use the Mobil1Vtwin 20w50 and really like it.

 

Sounds good.Thanks for the replys. Being a newer bike makes allot of sense. I will be switching in the next couple weeks. I found the Mobil 1 V twin 20/50 oil at a local parts place. I think I am going to go with that or maybe amsoil if I can find it locally. I ran the mobil 1 mx4 10/40 in my quad and it seemed to run very well and cooler.