Harley's New 20w50 Synthetic Oil : V-Twin Forum: Harley Davidson Forums

navyharley · 02-13-2003, 01:19 PM

Okay guys, I know we have about beat this synthetic horse to death, but Harley's new addition to the lubercation battle has put a new kink in an old question.

The problem: Harley just introduced "Synthetic Oil" just like it just came out, BUT they say that their Synthetic 20 w 50 oil is the ONLY synthetic you can use in all three areas of your Harley, Engine, Primary and Transmission. Do we believe Milwaukee or do we use our brand of synthetic and put it in all three, or do we believe Amsoil and put 20w50 in the engine, 10w40 in the primary, and 75w90 in the tranny?

10w40 is not to far removed from 20w50 so no problem, but there is a hell of difference between 20w50 and 75w90. What about it guys, anyone with some factual information on this quandry?

Thealien · 02-13-2003, 01:46 PM

Here are 147 threads that show up on a search on synthetic, there have been quite a few comments about HD's new oil and I doubt you'll get many replies as it will be redundant. Here are the THREADS

navyharley · 02-13-2003, 02:23 PM

Thanks Alien,
but like you I was trying to get a discussion going on Harley's new product and the deal of them saying you can use in all three. I view most of your threads you posted to me and all discussed the synthetics, but only one referenced what weights in which section and that was a reference to 75w90 in the transmission.
I have $20,000 investment I am trying to service myself, I am just trying to protect my investment. So which synthetic weight do you use in your tranny?

cwo2lt · 02-13-2003, 02:57 PM

I'd stick with the 75w90. It's designed for gear boxes and not as a multi purpose lube.
My Dad always said "A camel is a horse built by a committee" and I think that applies here. Besides, I don't like how the MoCo has been dealing with synthetics all these years and I don't see why I should support their sudden arrival in the 21st century.

Item for discussion: If the Harley 10w40 is good enough for the tranny why not any other synthetic? Seems to me the lighter weight would give better gas mileage. Anyone, anyone, Bueller?

navyharley · 02-13-2003, 03:01 PM

cwo2lt,
Are you running 75w90 synthetic in your tranny now?

wyodude · 02-13-2003, 03:27 PM

Quote:

Originally posted by Thealien
Here are 147 threads that show up on a search on synthetic, there have been quite a few comments about HD's new oil and I doubt you'll get many replies as it will be redundant. Here are the THREADS

Alien,

It ain't never gonna end

wyo

navyharley · 02-13-2003, 03:34 PM

Nope, learning never will, at least I hope not.

cwo2lt · 02-13-2003, 03:46 PM

Navy, Yes I am, Mobil1. I run 20w50 Castrol Syntec in the engine and 10w40 Syntec in the primary. Gas mileage went up, felt engine heat went down, engine runs quieter, tranny shifts smoother.

navyharley · 02-13-2003, 04:03 PM

cwo2lt, thanks so much. A straight answer finally LOL.

Thealien · 02-13-2003, 04:47 PM

Navyharley, not trying to be wise. I thought there was at least 2-3 threads that talked specifically about the weights. I believe any major name synthetic (Amsoil, mobil1, redline, etc) are all good. I use amsoil 20-50 in the engine and primary (it calls for 10-40 in the primary but for ease of stock on hand I use 20-50) and 75-90 in the transmision. I am very hard on my bike that is a 2000 1550 road glide so I even use the amsoil racing oil even though they say it is unnecesary. I have 45,000+ miles on my bike and it is quieter, shifts easier, cold starts easier, and runs cooler which is enough reason for me!! Good luck.

navyharley · 02-13-2003, 04:54 PM

Thanks for the info Alien, I do appreciate it. I need to change my primary and adjust the clutch now so I will most likely use 20w50. Still not sure about the tranny, the oil in there is thin, almost like a 10w40, but you are the second person who states they use 75w90, I will have to consider it.

Thealien · 02-13-2003, 05:04 PM

Gear oil is measured differently than engine oil, 75-90 gear oil is actually about the same viscosity as 10-40 engine oil (so I am lead to believe). Amsoil is the one who recomended the 75-90 weight and I have had no problems to date running it. You wouldn't believe how much easier it shifts, and quieter also, no clunk !!

SIDEKICK · 02-13-2003, 08:07 PM

alien answered first but gear oil numerical ratings do not correspond to lube oil ratings. ie... sae 50 motor oil and sae50 gear oil do not have the same viscosity. I believe gear oils numerical ratings are double what an engine oil would be.

Paladin1 · 02-13-2003, 08:45 PM

Navyharley, I am still a little nonplussed by the concept of using a 20w-50 in the transmission. However, other than intuition, I have no specific knowledge, nor have I heard any so far, as to why it wouldn't work very well.

Like many, I will wait untill I can read articles by specialists on their views, to try to evaluate for myself (and there will be many). I personally don't/wouldn't believe the oil manufacturers any more more than I believe the MoCo. Geez, what do they sell?

I personally have a lot of skepticism for most independent tests because i can't verify how knowledgeable they are or how independent. Like many, I think any good oil is way more than good enough for the life of any machine i have.

BMW motorcycles are "famous" for their cluncky transmissions, and it seems fairly well established that synthetic will make them smoother (it certainly did for my 99 R1100RT). However, that entailed using a similar weight oil (75-90 I think).

If enough articles accept the concept of using one oil, then i will likely switch.

Finally, I would not be surprised if ultimately the other oil manufacturers also endorse one weight of oil. Most would never have wanted to be the first, since it would never sell. ( I think even TheAlien might have resisted Amsoil 20w-50 in his transmission even if Amsoil said it was OK lol) The point is, this is a new concept, which is not intuituve to many of us, and therefore will take a while to catch on, assuming, of course, that it works well.

jmho, greg

navyharley · 02-14-2003, 07:53 AM

Thanks Greg,
Hopefully everyone will post there experiences and we can lessen the lessons learned LOL. As for now, I think I will do the 75w90 trick and see, Harley has NOT sold me on the 20w50 trick.
As far as viscosity of the engine and gear oils, I am not sure, However, pour some 20-50 into a pan through a funnel then pour some 75-90. There IS a difference.