Hey everyone, I got a '05 Sportster 1200 Custom. I was thinking about changing the oil at 500 miles, installing an oil cooler and switching to Mobile 1 synthetic(vtwin). And of course I would change the primary as well. I have been told that going to synthetic wile the engine is breaking in is not good because the oil is more slippery and the rings wont get seated right. But I understand that some companies ship their cars and cycles with full synthetic from the factory. What does it mean when people say "all 3 holes" when talking about oil changes?


-Eric

 

Engine, primary and tranny, which only applies on big twin. I personally think you can go to syn, but follow your warrenty.

 

The Screamin eagle bikes (like I have ) are shipped from the factory with Harleys Syn 3 in all three holes ( engine, Trans & primary) It will not cause you any problems at all to switch to synthetic oil. Just don't use the syn 3 in the trans. Use a gear lube like Red line shockproof heavy or others, you'll be glad you did. I went from Syn 3 to Mobil 1 in the engine and from what I see, I will stay with Mobil 1. I use the HD primary oil in the primary , has worked well for ions , not the syn 3 ( overkill) and redline shock proof heavy in the trans.

 

Ok sounds good. I am wondering one thing...for the trans/primary. The manual calls for sport-trans fluid. What weight of oil is it? If I can I will replace that with mobile 1 synthetic gear oil.


-Eric

 

You can run Mobil 1 or Amsoil 20W-50 in the crankcase and the primary. If it were me, I would wait until 1,000 miles but run fully synthetic from that point on.

When you change the oil in the primary, make sure you don't over fill which will cause slippage and hard shifting. When you reinstall the derby cover, make sure you tighten each bolt a little at a time using a crossing pattern. That will eliminate the possibility of seepage.

Based on where you live, I personally don't think you need an oil cooler, but that's your call.

If you don't have a service manual, spend $50 at the Harley shop and get one. It will be well worth the investment.