I just purchased a 1980 FLH Shovelhead with 16k miles on it...
The bike has only had Conventional oil in it. JWould it be ok to run synthetic oil or go with conventional oil?? The dealer told me I can but I cannot go back to conventional once I start using Synthetic which is not a problem. I have heard from other sources that if I put synthetic in it it will start leaking because conventional was run through it originally. Any info??

 

I am not a Shovel Head Expert but I happen to know one that runs Synthetic in everyone he builds with no problems. As for compatibility I can tell you that synthetic and petroleum are 100% compatible. You can also switch back to petroleum, although I don't know why you would want to. Even if you mix them all you loose is the extended drain capabilities of the Synthetic by introducing the undesirable elements that are inherently in petroleum oils. As for leaks. The same seal conditioners that are used in petroleum are used in Synthetic Lubricants.
If you have an engine that has had the oil changes neglected and you have a bad seal that is crusted over from the petroleum, Synthetic oil will find that bad seal by dissolving that crust. In that case fix the seal and put the Synthetic back in it..

Here is a link to what AMSOIL recommends for Harley's http://www.amsoil.com/products/stree...oil_chart.aspx Mobil is also a good choice.

Bear

 

Thanks for the info!!!

 

You can go back and forth from syn to dino oil all you want. It's not a good idea to mix them, though.

 

The ONLY time you would mix them would be if you where low and couldn't find any synthetic to top off with. Again, There is no harm done, just change it when you get back off your trip. You only loose the extended drain interval quality of the synthetic by introducing the undesirable elements that are present in Petroleum oil.

Bear

 

Be careful, the high detergent content of synthetics MAY dissolve varnish that has built up over the years and start leaks. A 1980 that has used, for instance, HD 360 all along may not take well to a change because of this. Lots report leaks with OLDER shovels from switching to syn after using dino for years.

The syn doesn't cause the leaks BUT exposes the dried out seals that already exist and are being masked by varnish build up.

EZ

 

I DO BELIEVE THERE IS AN ECHO IN HERE ...LOL

Bear

 

I use HD 360. I think the best thing you can do on a old shovel is change the oil offten. I change mine every 2000 miles. The oil can get nasty. I also use the modern drop in auto style oil filter. My bike has a chain oiler as well, so dumping syn oil on the ground is a waste.

 

LOL , Bear, YOU are an Amsoil dealer, MY response gave the answer credibility!

EZ[sm=popcorn.gif]

 

Personally, I'd run HD 360 in it, only because it has 16k miles on it with conventional oil. As mentioned there may be varnishes and waxes built up that are keeping things sealed (as is completely normal in any engine running dino oil) and the synthetic may dissolve away these deposits.

As for the switch itself, in an otherwise clean & healthy engine you can switch back and forth from dino to synthetic and vice versa as many times as you'd like with no problem. You can mix dino and synthetic oils in any ratio you want as much as you want- again with no ill effects because the two are 100% compatible. This can be verified at any oil manufacturer's website, and I'd trust their word over that of anyone else.

If you decide to opt for synthetic, Redline has a Group V-based synthetic 20W-60 specifically for older Knuckles, Shovels, & Pans, and it is what I would use:
http://www.racerpartswholesale.com/redline13.htm

Sounds like a nice bike- best of luck with it.