I have inherited 7 old British and German motorcycles that have been sitting for over 20 years. We used to use Castrol GTX 20/50 in them, but I have heard that the new automotive oil do not have the proper formulation for the older motorcycles. I have also been told not to run synthetic oil in them. I have been using synthetic in my 65 year old Harley with no issues. What is the true scoop?
Proper oil to use in vintage motorcycles
- Thread starter Crampfan
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I don't know about the true scoop but I've been running Mobil 1 4T in my ‘66 Bonneville for many years.
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Since they don't have catalytic converters, you can run oils which have zinc and phos levels in excess of the levels set by the fed to get a SN etc. rating. Do they have wet clutches? If so, is the oil shared with the engine oil?
Unless the bikes are very old or unusual where modern oils may be harmful (silver bearings on some of the real old stuff??), I'd go to synthetic by way of a few short interval changes. The Mobil1 m/c oils are made for shared sumps and still have sufficient zinc/phosphorous levels. They may leak more, but some are British so you are used to it 
. I use their m/c oils in my more primitive cars.
The reason for my initial caveat is way back where I learned to fly, one of the old timers had a hangar stuffed w/ some real old beauties; Vincent, Matchless, some Czech things, etc. He would run some of them on recip ashless aviation oil as he said modern vehicle oils weren't compatible with their bearings.
. I use their m/c oils in my more primitive cars.The reason for my initial caveat is way back where I learned to fly, one of the old timers had a hangar stuffed w/ some real old beauties; Vincent, Matchless, some Czech things, etc. He would run some of them on recip ashless aviation oil as he said modern vehicle oils weren't compatible with their bearings.
Originally Posted by jbutch
Any JASO MA oils should work, many HDEO oils have this spec. I"m not 100% but I believe so, hopefully somebody else will confirm this.
^ Agree with this. (Rotella T4 15-40 and T6 5W-40 are some)
Also as Langanobob said - The Mobil 1 4T 10W-40 is motorcycle specific, and I have also had good experiences with it.
Any JASO MA oils should work, many HDEO oils have this spec. I"m not 100% but I believe so, hopefully somebody else will confirm this.
^ Agree with this. (Rotella T4 15-40 and T6 5W-40 are some)
Also as Langanobob said - The Mobil 1 4T 10W-40 is motorcycle specific, and I have also had good experiences with it.
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My vote would be for some non synthetic Maxima green label
I've used this stuff in plenty of classic bikes
https://www.amazon.com/gp/product/B...;linkId=093a2ce9efb3c986632768e15661feba
I've used this stuff in plenty of classic bikes
https://www.amazon.com/gp/product/B...;linkId=093a2ce9efb3c986632768e15661feba
OP, you can't leave this thread without pics please!
Those older bikes are probably air-cooled and have looser tolerances and a lot more blow by and fuel contamination. You're probably looking at 2500 mile or 3000 mile oil change intervals at the max. Any dino oil in the proper weight for your climate will do the trick.
On all my 40+ year old British stuff I use Valvoline 20w50 4 stroke MC conventional. Cheap and easy to get.
On the older British bikes ,if you are keeping them at least, in addition to doing an oil change make sure the sludge trap is cleaned out. Sometimes it involves splitting the cases but they can take out and otherwise good running motor.
On the older British bikes ,if you are keeping them at least, in addition to doing an oil change make sure the sludge trap is cleaned out. Sometimes it involves splitting the cases but they can take out and otherwise good running motor.
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