Question on Lube Combination - Harley Forum

admin · #1 05-23-2007, 04:57 PM

Please tell me what the problems would be with this combination of lubes in my Softail FXST: Mobil 1 20W50 in crank & primary, and Mobil 1 75W90 (or 75W140) in tranny. I live in MI and purchased the Softail used but it was very well maintained.

Posted by: OneBlackFly on Feb 13, 06 10:25:49 am

admin · #2 05-23-2007, 04:57 PM

I dont know that you'd have any problems with the lubes you listed. I use conventional motor oil in my primary though - alot cheaper than synthetic for that application...since all your really doing with the primary is keeping stuff cool an slippery

The trick with oil - is to change it regularly and to use the right stuff for that application - for instance going with a good gear lube in the transmission is a smart idea.....

Posted by: steveb on Feb 13, 06 2:48:11 pm

admin · #3 05-23-2007, 04:57 PM

What puzzles me is that H-D says that SYN3 can be used in all three holes. Yet it seems to me that a heavier lube would be 'better' in the tranny. On the other hand, I've talked to several riders who indeed use SYN3 in all three and have had no problems.

Posted by: OneBlackFly on Feb 13, 06 5:18:49 pm

admin · #4 05-23-2007, 04:57 PM

If you use Mobil 1 in the primary, make sure you use an oil specifically designed for use with a wet clutch. If it doesn't have the proper chemistry, you may end up with a slipping clutch. Regular automotive Mobil 1 may cause you problems. It must be specifically designed for use with a wet clutch.

Posted by: BOSTY on Feb 13, 06 5:45:14 pm

admin · #5 05-23-2007, 04:58 PM

I believe that Mobil 1 20W50 MC oil is formualted for wet clutches. However, until convinced otherwise, I plan to use H-D SYN3 in all three places. Just wondered if there were any comments on the Mobil 1 lubes (since they are supposed to be good ones)

Posted by: OneBlackFly on Feb 13, 06 6:33:43 pm

admin · #6 05-23-2007, 04:58 PM

There's nothing wrong with syn3 for your engine or primary but if i were you i would go with a good gear lube for your gearbox. Have you ever heard of shear forces? Would you use motor oil in your manual shift truck or cars transmission? In many ways harley isn't always up to date, look how long it took them to start using synthetics!

Posted by: mtyevo on Feb 13, 06 7:00:34 pm

admin · #7 05-23-2007, 04:58 PM

Good point, and H-D has Formula+ for the tranny. I may use that in place of the SYN3 there.

Posted by: OneBlackFly on Feb 14, 06 4:58:36 am

admin · #8 05-23-2007, 04:59 PM

Another great product for the tranny is the AMS gear oil. AMS oil is a top quality synthetic. I use it their oil in my primary and main oil tank. My engine runs 10 degrees coller with it than it did with stock oil. The company says it can be used in the tranny as well, but since they offer the heavier gear oil I opted to get the best level of protection.

Posted by: 03FXST on Feb 14, 06 12:08:05 pm

admin · #9 05-23-2007, 04:59 PM

Many riders like the AMS lubes, but I've not seen them readily available, hence my original question about the Mobil 1 lubes since I can easily find them.

Posted by: OneBlackFly on Feb 14, 06 3:17:36 pm

admin · #10 05-23-2007, 04:59 PM

SYN3 by HD is the same formulation as Mobil1 V-Twin 20w-50. They make it for HD. Wife works at local HD Dlr last 7 yrs I get syn3 at cost +. Mobil told me to buy it, which in my book means they make it. They suggest (Mobil) that you can use the Vtwin in all 3 holes, but suggested useing their HD syn in the trans.

Posted by: Tipper on Feb 14, 06 4:41:33 pm