Reading on this site where suggested not to use synthetics with "poly" additives in the primary as is bad for the clutch. My indy recommended Amzoil 20w-50 in the primary, same as engine lubrication. What say ye, yea or nay?

 

The oil in the primary lubes the chain and cools the clutch, use what you want but I use primary specific non-synthetic oil. Can't see spending the extra money for syn in this application, it gets contaminated with clutch fiber and aluminum flakes from the clutch basket quickly.

 

I have heard of synthetics making the clutch slip.Some will say yes it will,some of course will so no way.I wouldn't put it in myself,just go with any kind of dino,or even ATF.

 

That's what I have in my primary now. Some would say it's over kill but I've used it in my
last 2 bikes and it works fine.

 

Mine works great with 10-40 Mobil one. No slipping...

 

This one gets some going.
On new bikes it does not seem to madder one bit. It really does not do anything good or bad for the primary.
The old idea was that syn engine oil inthe primary some how was bad for the clutch. Of all the riders I know that just made life easier by putting the same oil in primary as the engine, none have had a clutch problem and they rack up some miles.
It cost more than a plain old primary lube but then again 38oz every 10K whats the big deal for a couple bucks.
If it makes stock the oil and lubes easier for .
I have two bikes A TC103 and an EVO to keep it simple I use the same lubes in both and have no problems with either.
Most 20/50 high end syn engine oils sold today are recommend for primary also.
Your ride your call

 

general rule if the donut on the back of the oil container doesnt say energy conserving it wont hurt your clutches if it does it has friction modifiers and you shouldnt use it on wet clutches.

 

I've been running Mobil 1 ATF in my primary for a long time. No issues, no clutch slipping.

 

Mobil on their web site does not recommend using it ATF in primary they state lubing the chain as an issue.
Of course your ride

 

Whatever a motocrosser uses in his 2 stroke bike's gearbox, if he still has the bike, will work best in the primary of a Harley.
I use Bel Ray Primary Lube, it's the same formula as Belray gearsaver, 75 or 80 weight.
Think of the abuse my KX250's gearbox gets. It still shifts great with the Belray in it.