Mobil 1 20W50 V-Twin with 8.5% BG MOA EL

I have tried Maxima MTL 75wgt which is a 2 stroke transmission oil equivalent to a 30wgt engine oil, I had run it in my earlier 650SS and Atlas with no problems but was surprised when i inspected the clutch on my previous Mk2A as there appeared to be a reaction to the sintered bronze plates as its a GL5 oil I am assuming there was a start of a reaction to the bronze plates.

Edfury828 said:

I did see in an ad for the Bel Ray Sport that it is 80-90W. The reason I asked if it was 20-50 is I'm thinking constancy or thickness may be what dictates the functionality of the tensioner.

I have heard that ATF is basically 10W which, I am speculating the "thin-⁷ness" of is what causes problems for at least some people with the hydraulic tensioner. So, with that line of reasoning, at least the Bel Ray Sport is not likely to be too thin.

Does the Bel Ray seem to you to be a very thick gear oil, or since it seems to be unique, could it have a 20-50 like (or less) consistancy? I like that it keeps everything so clean in the primary, so I'm hoping it could work.

Thanks for your input too Glenn. It is interesting that the ATF does work in some MK III's!

My concern is that being new to Nortons and with my ears not being what they used to be either, if I get chain slap I will know it?

As I'm just getting mine out on the road, I'm trying to be conservative and start with a simple and dependable Norton. Once I become more intimate (lol) with it, then make changes if needed.

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The table here might help…

The Belray appears to work fine in my mk3 primary. Tensioner seems happy. Clutch is not affected. But, less than 4,000 miles and I change it every service, so less than 2,000 miles, more like 1500 between changes.

As I'm now seeing it, the BG (brand) MOA is an additive that you buy and add separately. Now I get it!

Although the Mobil 1 V twin oil rates near the bottom of the "Stage 1 performance" category, that puts it above the "Stock Low Compression" category in which my bike realistically belongs.

Load Capcity 178
Total Heat From Friction 1.80

That should be adequate, however...

The Royal Purple HPS 20-50 rates right in the middle of the "Extreme Protection" category with

Load Capacity of 457 and
Total Heat From Friction at 0.44.

It also says it has the max ZDDP allowed by the API and is good for all flat tappet engines.

It is readily available as well, at about $10.50 qt. from Amazon ($62.81 for qty-6) with free delivery. That's $3.00 qt. Less than I paid for the Mobil 1!

So, I'm thinking I'll go with that for the engine. With the Bell Ray Sport oil for my MK III primary.

BTW, if you used Bel Ray Sport in the gearbox and primary, you wouldn't need the push rod seal, lol!

Edfury828 said:

I have decided to go with Mobil-1 20-50 for my MK-III engine and primary with hydraulic tensioner, since it's pretty good and readily available.

The Mobil-1 I'm finding is API-SJ and says it's good for bikes that require SH, SG, CF as well. The bottles also say reccomended for Harley Davidson V-Twins.

I know Mobil-1 20-50 is one of the top rated engine oils from Jim Comstocks list, but I think things may change, or there could be variations.

Do I have the right Mobil-1 For my engine, and will it also work well in my MK-III primary?

Thanks,
Ed

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Mobile-1 is recommended by John Favill

uneasy rider said:

Mobile-1 is recommended by John Favill

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That's interesting! And if I'm understanding things right, the Royal Purple scored higher on the tests done by Jim Comstock.

I'm sure either oil is very good and would work well, especially for my stock bike which will not see much abuse. I just had to pick one!

If the MKIII primary-chain tensioner get gummed up and the bleed holes plugged, it won't work properly regardless of which oil you use in the primary. Take it apart and thoroughly clean it when you clean the clutches. Make sure you get it right side up and that the sheet metal gizmo has the wide part of it facing up; that funnels oil dripping off the primary chain into the device. It will clatter on startup at first till it fills up with oil.

If you have the factory bronze plates they will react with GL5 gear oil, even if it gets there from the gearbox,which also had bronze bushings. I would use straight mineral oil in the gearbox or GL4 if you can't get mineral oil, not GL-5.. Mineral oil is also specified for many heavy truck transmissions that have synchronizers such as GM Sm420s and SM465s and Fuller Roadrangers, so film strength isn't an issue but lubricity and corroding bushings are.

The story on the bronze plates is that they came from an Austin automatic transmission. A one-time girlfriend of mine had a new Austin America with an automatic trans that worked fine. The rest ot the cr not so much.

Edfury828 said:

That's interesting! And if I'm understanding things right, the Royal Purple scored higher on the tests done by Jim Comstock.

I'm sure either oil is very good and would work well, especially for my stock bike which will not see much abuse. I just had to pick one!

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To be more specific, he said Mobile 1 V-Twin. It has enough zinc in it.

To each his own of course.

But IMHO Jim did an absolutely excellent job with all of that testing.

Given the cost of a rebuild, even the most expensive oil is extremely economical really.

Personally, I cannot imagine choosing to buy any oil that is not on Jim’s first page. I just cannot see the point in knowingly using something that is sub optimal.

But that’s just me.

Fast Eddie said:

To each his own of course.

But IMHO Jim did an absolutely excellent job with all of that testing.

Given the cost of a rebuild, even the most expensive oil is extremely economical really.

Personally, I cannot imagine chossing to buy any oil that is not on Jim’s first page. I just cannot see the point in knowingly using something that is sub optimal.

But that’s just me.

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Jim did a beautiful job on my 75 exhaust threads. Great oil tech session at the NY Rally. I hope he can make it to NH this June.

Fast Eddie said:

To each his own of course.

But IMHO Jim did an absolutely excellent job with all of that testing.

Given the cost of a rebuild, even the most expensive oil is extremely economical really.

Personally, I cannot imagine choosing to buy any oil that is not on Jim’s first page. I just cannot see the point in knowingly using something that is sub optimal.

But that’s just me.

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Can't argue with that logic.
The slight problem that I encountered was that the first page has just 3 oil types in 20/50 that are available here. Many of those first page oils are mixes, which I'm not interested in doing. I think Jim talked about that and recognized that for most of us its best to avoid mixing oils, but he was interested in the results of those experiments.
None of the three or four first page 20/50 oils are readily available when out on the road here, so I have generally used Vr1conventional racing oil, which is on the next tier down. It is available at most auto parts stores in North America.
The Castrol XL Classic is on Jim's first page but I haven't found it here in Western North America. Fortunately Castrol has created a new high zddp oil called GTX Classic which is very similar in makeup to the UK Castrol XL Classic. It's also very reasonably priced and easy to find, so I have been using some of that. I don't think it was available when Jim was doing his testing.
It did very well in wear testing done by this fellow.
Here he talks about recent improvements to VR1

A comparison of wear with low zddp Castrol GTX vs high zddp Castrol GTX Classic ( very similar makeup to UK Castrol XL Classic)

I just changed the oil in my Mark III and put in Kendall 20/50 (have to go to the garage to see which one) Was recommended by two people who I thought knew what they were talking about. Now I see its not recommended. Suggestions?

If you aren't concerned about price or on road availability the Belray xps 20/50 4t tested near the top as did the Royal Purple HPS 20/50. They can be ordered online.
At about half the cost you can find Castrol GTX Classic 20/50 which Jim did not test. He did test Castrol xl classic 20/50 , which I have only found in the UK and Europe. It tested high enough to be in the top group and I believe the Castrol Gtx Classic 20/50 would also be in that group as it has nearly the same chemistry.
Valvoline Vr1 conventional Racing oil tested quite well and made the second group in Jim's test. According to the oil analyst in the videos I posted, the newest version of vr1 conventional offers quite a bit more protection than the old vr1, so it might now be in Jim's first group if tested today.
In real world testing I have run the Vincent Rapide 60,000 miles on the old Vr1 and it measures just over one thou of cylinder taper now. One thou in 60,000 miles is a spectacularly tiny amount of wear.
Hastings recommends reboring at 12 thou or more of taper.

There is also a synthetic version of vr1 racing oil and that did not test well. If using VR1 make sure to get the conventional type. If using Castrol GTX make sure to get the Classic type, not the regular GTX.


Glen

I just checked. It's Kendall GT1 with added zinc. I don't know if that is the same oil that Jim tested.

Thomasa said:

I would stick with ATF for the primary and change it every time you change the motor oil to save the sprag clutch. GM/Dexron will give you a smoother takeup while Ford type reduces slippage. There is a seal available for the clutch pushrod that keeps gear oil out of the clutch. Get one. Gear oil is a primary contributor to gummy clutches that both drag and slip. Also don't park on the side stand for prolonged periods; that also contributes to gear oil running into the clutch.

You do realize that Harleys have roller tappets and Commandos do not. I do not know if Mobil 1 has enough zinc/ZDDP etc. to lube flat tappets.

MkIII engines had a reputation for flattening camshafts in less than 20K miles. There were also those soft cams in the spares supply for years after last MkIII production. I have had two teardowns for cams on my MKIII before I installed a known good work-hardened cam. No trouble in many years and miles since but I use a ZDDP additive and Castrol GTX which is supposed to have enough zinc anyway. That's also what I use in my Atlas that has the original cam.

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Thanks for the info

Clutch rod seals are available from Atlantic green technologies

uneasy rider said:

Clutch rod seals are available from Atlantic green technologies

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Back in the day I made one with a felt washer and a spring. It's still there to this day and the clutch stays clean with an occasional oil change.

uneasy rider said:

Clutch rod seals are available from Atlantic green technologies

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I got my Atlantic Green (Dyno-Dan) clutch rod seal from CNW with my "EZ Pull Clutch Kit" since I had mixed and matched clutch discs with one bad disc, I wanted to start with a "known quantity".

Btw, the smell of gear oil almost knocked me down as soon as I cracked the primary cover open. There was no doubt I needed that seal! I also got a Dyno-Dan starter from British Cycle Supply. Great customer service, and a US warehouse for US customers!