What Oils for Air Cooled Street Thumper?

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Given that lots of people spend far more time reading oil analysis results than I do, what oils should I be looking at using in my new air cooled Royal Enfield that shares engine and tranny oil? The book calls for 15w50 ester based semi synthetic. I have 2000 miles on BMW 15w50 semisyn (3 changes in that time), and 1000 miles on Motul 300v synthetic. What oils should I think about using for the long term? I am a little curious why the book calls for an ester based semi synthetic instead of a full synthetic. It would seem to me that a full synthetic would have to be better.
 
20w-50 motorcycle-specific oil since you have a shared sump. Don't worry about the ester or semi-syn requirements.

Mobil 1 20w-50 is easiest to acquire. I like Red Line oils, and they're ester-based if that helps. There's a recent UOA here showing Amsoil performing well. Motul would be great too.

So, pick whichever is easiest for you.
 
Id be inclined to run something very robust such as Redline in an air cooled engine. Also gobs of zddp in Redline.
 
15W/50 Mobil 1 is perfect for this application.....Does not have the dreaded friction modifiers that make wet clutchs slip, and is plenty robust, lots of ZDDP. And comparitively inexpensive, available at some Wallyworlds in 5 quart jugs.
 
Originally Posted By: carock
... what oils should I be looking at using in my new air cooled Royal Enfield that shares engine and tranny oil? The book calls for 15w50 ester based semi synthetic. I have 2000 miles on BMW 15w50 semisyn (3 changes in that time), and 1000 miles on Motul 300v synthetic. What oils should I think about using for the long term? I am a little curious why the book calls for an ester based semi synthetic instead of a full synthetic. It would seem to me that a full synthetic would have to be better.


1. Use what the book calls for, however boring that seems to be, yes, we all get caught up in it.

2. The reason the book calls for a semi syn is the same. The motor company knows there are some elements of conventional oil that have lubricating benefits for the engine.
These elements get destroyed when oil is super refined into synthetic and also missing from true ester synthetic.

3. Many people think synthetic is the end all of all good oil and superior to any conventional. That is not entirely true, it really depends on the application and intended purpose.
Oil companies of course market to the public since the public thinks that way and they make massive amounts of profits on it.

There is a reason, Harley, Indian, Victory, Yamaha, Enfield, etc, etc, etc are semi synthetics in their OEM oils. Lets not forget even Marine Engine Companies as well.
Im not saying good or bad, not what this post is about, but just calling an oil "Full Synthetic" does not make it superior to Conventional, It depends on what you are trying to achieve, balancing change intervals with wear and of course the design of the engine as well as the operating conditions and materials used.

With all that said, like anything, you can pretty much use what you want it jsut if you want to trust the maker of the product over your own feelings.
 
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Check your owners manual for a spec for the oil needed in your bike. Then shop around for a oil that meets that spec. And it doesn't have to be the factory brand sold oil. If there's a motorcycle specific oil available, you pretty much won't go wrong by using it. They are usually available in bike shops or auto part stores for better prices then at the dealer. It is funny that some mfgrs say not to use synthetic oil vehicles, but you know there are big numbers of people doing it without issues from it. If you really want to waste money you can shop at your local Harley dealer and buy their oil. Syn 3 is a full synthetic and if you only need a qt or 2, won't brealk the bank. They say it can be used in the motor , trans , and primary of their bikes ,so it a one size fits all oil.Here's what Harley says about it.Q: Is SYN3 a full- or semi-synthetic?

A: SYN3 is a full synthetic lubricant. It is the general practice in the industry that a "True Synthetic" is formulated with Group IV Polyaplhaolefin (PAO) basestocks. SYN3 is formulated with PAO basestocks and is a "True-Synthetic".,,
 
I've always ran 15 40 supertech diesel oil in my dual sport. Never had a problem with it
 
Unless you want to push your OCI beyond 3000 miles I wouldn't get too caught up in using synthetic or semi-syn. With that said:

Valvoline 20W-50 seems to be the go-to for conventionals.

As for syns, Castrol Power RS 4T 10W-50 is available on Amazon in a 6 pack, sometimes discounted to a little over $40. Factory fill for Triumph, works pretty ok. Mobil 1 15W-50 available virtually everywhere.

How do you like it so far? I've been drooling over the new Enfields for awhile...just haven't had the nuts to pull the trigger.
 
Motul makes a motorcycle specific semi-synthetic ester blend called 5100 4T in 10W50 and 15W50 - quite a bit less expensive than the 300V you're running now.

Just a guess on the why the ester-based semi-synthetic - maybe RE think you'll like the shifting better than a petroleum-based oil.
 
Any of the MC 20w50 oil at Autozone or AAP or other national auto parts chains should do fine. I use Castrol 4T 10w50 in my Triumph.
 
The Enfield is the 2014 Chrome C5 model purchased new and has 3165 miles on it so far. The most surprising think about the bike is how smooth it is. There is much less vibration than an old Triumph 650 or Harley Sportster. The vibration up to 55 mph is very mild and actually feels pleasant. The most vibration I ever get from the bike leaves a slight tingle. The vibration decreases with each mile, so it may continue to get smoother than it is now. The bike can easily cruise at 65 mph all day long.
Most of my prejudice for synthetic oils comes from building air cooled VW's in the 1980's. It was pretty obvious that Redline oil would not develop any carbon deposits and the engines stayed very clean inside. I plan in 2000 mile OCI's with this engine. I would prefer to run a 20w50 because they are easier to find, but I am not sure if that would effect the warranty. Right now it looks like Motul 5100 15w50 is going to be the standard choice until the warranty expires as it sells for $38 per gallon with shipping on Amazon.
 
Originally Posted By: 4wheeldog
15W/50 Mobil 1 is perfect for this application.....Does not have the dreaded friction modifiers that make wet clutchs slip, and is plenty robust, lots of ZDDP. And comparitively inexpensive, available at some Wallyworlds in 5 quart jugs.

I agree.. Another sleeper alternative would be 20w50 Havoline conventional. It's a surprisingly robust oil that does well in shared sumps.
 
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Are you guys sure that using a motor oil not specifically designed for a motorcycle's combined clutch/transmission is the ideal solution for the long term? I have been wed to this concept for a long time but have never researched it much. I am sure it has been talked to death on this forum but I can't find the relevant thread.

Also I have some additional input. My OCI will be 2000 miles. Will a conventional oil or semi synthetic like Motul 5100 15w50 actually protect better than a full synthetic like Motul v300 with the shorter OCI? Another quirk of the Royal Enfield engine is that it has a 2.75 liter capacity, but you can only drain 1.75 liters of that during an oil change. This is one of the reasons for the short OCI.

My Moto Guzzi runs with Motul 7100 10w60 and based on hot idle oil pressure and experienced user recommendations it needs this type of oil, so I keep it in stock. What would happen if I ran the same oil in the Royal Enfield?
 
Originally Posted By: carock
Are you guys sure that using a motor oil not specifically designed for a motorcycle's combined clutch/transmission is the ideal solution for the long term? I have been wed to this concept for a long time but have never researched it much. I am sure it has been talked to death on this forum but I can't find the relevant thread.

Also I have some additional input. My OCI will be 2000 miles. Will a conventional oil or semi synthetic like Motul 5100 15w50 actually protect better than a full synthetic like Motul v300 with the shorter OCI? Another quirk of the Royal Enfield engine is that it has a 2.75 liter capacity, but you can only drain 1.75 liters of that during an oil change. This is one of the reasons for the short OCI.

My Moto Guzzi runs with Motul 7100 10w60 and based on hot idle oil pressure and experienced user recommendations it needs this type of oil, so I keep it in stock. What would happen if I ran the same oil in the Royal Enfield?
If you read thru all the UOA'S, you won't find one reference to whether an oil is "designed" for a car, truck, motorcycle or boat from Blackstone or any other testing company. So if your wondering if using an oil that is mostly designed for trucks will hurt you motor in the long run, as long as it has what all motors need you won't have problems. Some bike oil mfgrs recommend their oil can be used in a wet clutch situation or in the transmission,As well as the motor. Thousands of people run their oil that way without issues.Bikes like Harley's have 3 compartments for oil ,Sportsters have 2. So you can tailor your decision as to what oil to use in each. It's been that way forever and it works. Oil doesn't know or care what it's being used in. It just does it's job. Some better then others, and some better then what the people that made the bike say to use.Unless you shop for oil at the dollar store, it's pretty hard to find a bad oil these days.,,
 
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