I have an 03 fatboy, I don't know what oil is in it. I bought synthetic oil today. Is synthetic oil ok to use? I hear alot of perspectives on this. One guy told me that my gaskets would leak switching to synthetic. I am learning about this bike. I have been out of bikes for 20 years and I bought my fatboy last spring. I run snowmobiles and I run synthetic oil in them, but they are also two stroke. They have required synthetic oil since 2001. Not sure about my bike. Any help would be appreciated. Thanks

 

Hey..you will be ok with syn..just stay with it from this point on..I wont tell you a brand,get your flavor you like...you wont hurt your bike..gl

 

Todays synthetics will not hurt your bike. But get a motorcycle rated synthetic like Mobil1Vtwin, Harley Syn3, Amsoil, Royal Purple, Redline, Spectro etc. Your should use a 20w50 in the engine and a Harley filter speced for your bike. You will get great performance from a 75w90 or 85w140 synthetic gear oil in your trans. In the primary you can use the 20w50 or HD formula + or even synthetic ATF. If you bought automotive 20w50 then don't run it past 2500-3000 miles as the anti-wear additive packages are not as robust and Harley Vtwin engines beat up and shear the oil pretty quickly.

 

One thing I've learned after owning and being around Harley's for close to 40 years is that the V-Twins aren't very smart engines, and as long as you change the oil at reasonable intervals they seem to be happy running just about anything that says "oil" on the container. Bike owners fret much more about the specific type of oil being used than the engine itself.

That being said, the majority of guys I know with high mileage bikes (85,000+ miles on the original engines) are running regular Mobil 1 Synthetic 15W50 oil, the same stuff you can purchase in 5 quart containers for around $21.00. Up until recently I also ran it in my 2003 FatBoy here in the lower midwest where summer temperatures of 100+ aren't all that uncommon. If you want to pay twice the price for "motorcycle specific oil" that's also fine but not necessary.

I also know quite a few that run nothing but Rotella T 15W40 conventional oil which only costs about $2.50 a quart, and think it's a waste of money to use anything else. They are using it in Shovelheads, EVO's, and Twin Cams, with zero problems, even on high mileage engines.

Come to think of it, I don't know of anyone that has had a major failure that was caused by the type of oil being used. Most engine failures can be tracked by to rider error, lack of scheduled maintenance, etc...

I guess if you want to extend your filter and oil changes out to as many miles as possible a higher end synthetic oil might be beneficial, but I believe in changing the oil and filter every 2,500 to 3,000 miles no matter what I am using. Under those conditions any synthetic group 4 oil (Mobil 1, Amsoil, or many others), or group 5 oil (RedLine and others) is probably 'overkill', but I don't care, as a few quarts of oil aren't that expensive and I like to run fresh fluids.

In my bikes I also run Mobil 1 75W90 Gear Lube in the tranny and Rotella T 15W40 conventional oil in the primary. Usually change the tranny and primary fluid every 5,000 to 6,000 miles (or whenever I happen to think about it).

But anyway, your Softail will be perfectly happy running just about any synthetic. Just change the oil and filter at a reasonable frequency and you are good to go....

 

Thanks for the information guys, I feel better about using it.

 

Just stay away from Syn-3, Royal Purple and a couple others that are really pour quality.
Try Dynacycle oil, Mobil 1 or Amsoil.

 

Hey Irongirl,I ran syn-3 for 16k and when I took things apart for big bore all was fine,also what is wrong with RP....just so you know mobil-1 now

 

All the spec's on both syn-3 and Royal Purple are very low quality.
Check out many sites on the web and you can see many test results.
I found info on Dynacycle Oil's site and on Amsoils site. Then I went digging deeper and found out all kinds of info on oils and was shocked on how poor the quality is on some oils, Harley's especially.
Did you know that when Harley came out with Syn-3, Easy Rider magazine did a test on all the new oils that were coming out for Harley's and found that Syn-3 was one of the worst.
Harley threatened a law suit against Easy Rider and they had to print a retraction even though their findings were accurate.
Harley didn't want anyone to know how bad the oil really was. Now that so many riders aren't educated enough about oil, they just follow what H-D tells them. Very sad !!

 

At least you can find specs for syn3 and Royal purple.Haven't been able to find any on dynacycle , except its not a synthetic oil just a blend which means old technology and more then likely nothing special.,,

 

Have you looked at any spec's on it?