!997 Road King Evo. I am pretty sure that I will be saving some dollars and using Mobil Synthetic for the engine, but not sure what to run in the primary or Trans. I don't want to mess up my clutch by using synthetic in the trans. What works? Thanks, Fly

 

You are not going to "mess up the clutch" by putting synthetic in the tranny. The tranny oil doesn't go to the clutch. You bike originally came with HD Semi-synthetic in it.

 

I have been metrics until now. What oil does the clutch ride in?

 

Primary oil, which is basically motor oil. Some guys use ATF in their primary as well. Prettu much all the oil in the primary does is lube the chain.

 

The clutch is in the primary.

 

I have used Harley Davidson Formula + in the tranny and the primary and Harley Davidson 20w-50 in the engine on my 2006 Dyna.

I have changed the oil in all three holes at 500, 1000, 5000, 10000, and just a couple of weeks ago at 15000. I have had no problems what so ever to speak of.

 

Over in the 'Oil Forum' there is a poll (and a bunch of other threads) about what everyone uses in the tranny and primary....

As far as what is best, if you ask 10 people you will probably get 10 different answers.

That being said, myself and most of the guys I know use Mobil 1 75W-90 Gear Lube in the tranny, and Mobil 1 20W-50 V-Twin in the primary.

In the wet-clutch system you should try and use a fluid without friction modifiers, and has a JASO-MA rating. The JASO-MA rating means that very few (if any) friction modifiers have been added. BTW, both Mobil 1 V-Twin and Amsoil have that rating.

But I'm sure other fluids will work just as well.

 

I use HD Formula+ in the Primary, HD 20W50 in the engine and Redline Shockproof Heavy in the transmission.

 

RED Line (period) in all 8 holes

 

I use Red Line Synthetic(heavy shock proof/trans....MTL in the primary)in all three holes, and I am happy with its performance. I dont like staying with just one brand for the life of the engine though, for several reasons that I will not go into right now.....so I do like to switch off to Mobil-1, or Amsoil, after each oil/filter change.....but they are about the only three I use. I do like to use the HD branded stuff during break in on a new engine, and then switch to one of the above fully synthetics after about 2000 miles.