Semi-Synthetic in a 107 M8?

Reply Subscribe

Thread Tools

Search this Thread

Mar 3, 2020 | 04:10 PM

DinoM

Thread Starter

Tourer

Joined: Jul 2013

Posts: 455

Likes: 73

From: New Hampshire

Semi-Synthetic in a 107 M8?

Hey Gents,
Wasn't sure if this should be posted under "Oil" topics or here under M8. I did do a search looking for info to my question but couldn't find anything so here goes....
Is it okay to run a semi-synthetic blend, just in the crankcase, on an M8? Just made the change from an 88 TC to an M8 and I've always used Penn's Grade 20W-50 in the crank. It's actually green oil that is a semi-synthetic blend.
I wasn't sure if the M8 required full synthetic or not. Bike never came with an owner's manual so I can't check that either. That and a service manual are the first things on my list to purchase!

Thanks in advance!!!

Mar 3, 2020 | 04:20 PM

mjwebb

Seasoned HDF Member

Joined: Jan 2008

Posts: 13,621

Likes: 11,353

From: State of Confusion

Quote:

Originally Posted by DinoM

Semi Synthetic isn't as prevalent these days but Extra Virgin is available at most all supermarkets

Mar 3, 2020 | 04:28 PM

Seasoned HDF Member

Joined: Jan 2006

Posts: 11,467

Likes: 2,996

From: Charleston, SC

You can use it. Owner's manual is available on the HD website BTW under owners manuals: https://serviceinfo.harley-davidson....cle/lookupForm

Mar 3, 2020 | 04:50 PM

mjwebb

Seasoned HDF Member

Joined: Jan 2008

Posts: 13,621

Likes: 11,353

From: State of Confusion

okay, I'll try and be serious and helpful..is this what you are planning on using? if so, yeah some use automobile oil, and some racing formulas of it...but I can't see how that would be the best choice for Harley engine applications, although the reality is as long as there's oil in the engine and changed per recommendations, guess that's good enough

PennGrade 1® Partial Synthetic SAE 20W-50 High Performance Oil

Please Note: Penn Grade 1 High Performance Oils contain high zinc and phosphorous additive concentrations which can be detrimental to cars and trucks with catalytic converters.

edit: there's so many to choose from, but if you want to take the guesswork out of it just use the recommended Harley Conventional HD360 20W50. After all, it has been the factory fill for all Harley non CVOs for probably close to 20 years now and they didn't see the need to change anything for the M8s, which tells us it's been in circulation long enough for them to trust it's working great.

Last edited by mjwebb; Mar 3, 2020 at 05:10 PM.

Mar 3, 2020 | 05:19 PM

Silentgreyfellow

Tourer

Joined: Apr 2019

Posts: 367

Likes: 264

From: Massachusetts

Penn grade one is good stuff. I run it in my 98 lowrider. I'll be putting it in my 18 RKS as well once the cats removed cause the high level of zinc will destroy the cat.

Mar 3, 2020 | 05:27 PM

user 47363638

Banned

Joined: Dec 2017

Posts: 4,506

Likes: 2,361

Oil is oil, your engine doesn’t know the difference, I use what ever is on sale.

Mar 3, 2020 | 05:54 PM

DinoM

Thread Starter

Tourer

Joined: Jul 2013

Posts: 455

Likes: 73

From: New Hampshire

Thanks Gents!
This is what I've been using....
https://penngrade1.com/products/high...il-sae-20w-50/
Not the V-Twin...
So I guess with my 05 it was probably fine being there's no cat in that bike. Probably a different story for the M8 then. It's essentially the oil my mechanic has used in all of his bikes and what he recommended to me a long time ago. Been using it ever since. And I have to say I noticed a considerable reduction in top end noise going from Mobil 1 V Twin and even more from Amsoil. All 20W50. But if this stuff is gonna mess with my cat, maybe its not a good idea to use it. At least until I decide to change out the exhaust....

Last edited by DinoM; Mar 3, 2020 at 05:55 PM.