This is actually two different questions. I have a 2001 SE RG with 21,000 miles and purchased 20W-50W for the engine and primary and SGL for the trans. Just like any topic you get different opinions and putting synthetic in the primary is one of those. It appears about 80% say it is fine and 20% say it could be an issue with an older clutch or they thought the clutch maybe slipping due to the change.
The first question is has there been any issue with the Amsoil 20W-50W MCV in the primary with clutch slippage? My clutch works fine with the HD oil but yesterday at 20 degrees the clutch did pull a little hard but I only rode for a fewfeet anyway (had to clean the garage). The other question is at what number of miles (on average) should the clutch be rebuilt?

 

I have never heard of anyone having problems with an Amsoil product. The hard pull on your clutch is probably clutch "drag" from the oil being cold. Very normal. If it doesn't disappear after the bike has been warmed up a few minutes you may need a clutch adjustment. I use Redline MTL in my primary because it has a very thin pour point and reduces the cold clutch drag I was getting with 20w50. As for "average" clutch life. That depends mostly on your riding habits versus oil.

 

20w50 motor oil is fine in the primary reguardless if dino or synthetic.

Like KBFXDLIsaid, it was probably due to the oil being cold. 20w50 is very thick until it is warmed up. Take your time and allow the engine to warm up properly. Let the bike idle until the valve covers are hot/warm to the touch.

Having said all that.....I personally like diesel 15w40 in the primary. It seems to warmup faster and is not as thick as 20w50.

 

Agree with the above BUT Type F ATF seems to work great too and is lots cheaper. The objection to synthetic oils in the primary (therefore in the clutch basket) is that they are too "slippery". That appears to be a myth although some of the lighter oils (5W20 or 30) probably have too much friction lowering additives to be good in the clutch.

Both MTL and Type F atf have friction modifiers that work to increase clutch efficiency, the opposite of modifiers used in light weight motor oils.

EZ

 

Used nothing but HD dino oil in my 2000's primary since new. I have 69k miles on the clutch. I have only had to adjust it once. That was after a foolish day of doing slow races at a bike show, beating everybody that entered, and finally ending up getting whooped by a kid on a bicycle.

 

I like the MTL because it is as thin as a 5w30 motor oil but has a GL4 gear oil rating so I know I'm not going to wear it out. Plus it has no moly in it.

 

KBFXDLI, you might want to try the Type F atf. It behaves very similar to the MTL which I used for several years. I suspect they are very similar in performance and the atf is so much easier to get and less expensive that I really think it is the way to go.

I changed on the advice of friends with lots of miles and years on their scoots swearing by using it. I never was big on using engine oil in the primary but think it is fine too, especially a dino 10/30 or 40 without friction modifiers. Mostcheap store brands would qualify too.

EZ

 

After looking into the Amsoil synthetic a little more I am not as sold as I was when I bought it. It appears that some are also experiencing more engine noise when using the synthetic in the engine. I am in the process of changing my cams and chain system to the new roller chain set-up.If I make the conversion to synthetic now and the engine in noisierI will not know for sure if it is the oil or the changes that I made. I mayjust hold off changing to synthetic.

 

Whenever I develop a leak in the primary area....I usually switch from the diesel 15w40 over to ATF. Having all three different fluids in the bike....really helps me figure out what is leaking.

When I rode Shovels, I would seal the primary off and use nothing but ATF. I have to say that ATF works great....at least for me.

However, some use to say that with high mileage bikes, the ATF would eat at the adheasive material that keeps the magnet glued inside the rotor. In a short time, the magnets would fall off and take the stator out. I only heard this with high mileage bikes and have not heard this in a long time....like at least 15 years ago. It never happened to me, but then again I never kept a Shovel for more than about 20-30,000 miles before I traded it. I don't know if this rumor holds true or not......something to think about though.

 

Who knows. They used to believe syn oil made bearings "skate" too.

Lots of non-official lubes have been blamed for things the factory doesn't want to take responsibility for, as we all know.

Be interesting to hear from someone who knows more about the chemicals involved if Type F fluid can cause some kind of disolving of adhesive used to hold the stator together. Seems those can fail pretty often WITHOUT ATF too though.

EZ