1958 AJS 16MS - Oil types

[Ian Heaton]

Good morning all!
Have now taken delivery of my AJS 16MS - 1958
Can someone tell me what oil and grade to use with the bike. Can a fully synthetic oil be OK (and if so what grade)?
Hope someone can help
Ian

[MAC]

Seems to be contention between using multigrades such as SAE 20/50 or straight mono grades e.g. SAE 30/40/50 mineral oil.
Personally I use 20/50 in the chaincase and straight 50 in the engine of my 1958 M18S. I only use the bike in the summer months now so do'nt bother changing to a lighter winter grade.

[Ian Heaton]

Hi MAC - many thanks for that!

[SPRIDDLER]

Which oil? is a contentious topic with many discussions on here and many opinions.
In my singles I've always followed the original manuals which can be found here under 'Books'.

http://archives.jampot.dk/

That is to say I've used monograde 50 in the engine (all year) and g/box and mono 30 in the primary chaincase.

FWIW a couple of my personal reasons for using monograde are:

- Multigrade is a fine oil and makes starting a bit easier in cold weather but has a detergent additive which *may* dislodge sleeping/harmless crud that's settled over time in the engine and oil tank.

- Multigrade has advantages in twins which have shell main and big end bearings and which require oil under high pressure but which is not the case with singles which have ball main and big end bearings fed by low pressure 'dribbled' and splashed oil.

- Multigrade has anti-friction additives so may not be good in the chaincase and I don't want it on the clutch plates.

- Synthetic or semi-synthetic has been developed in part for long life in today's modern engines which require infrequent oil changes. It's expensive and I've changed my engine oil about every 1000 miles as per the manual as a matter of course.

- Modern oils may be 'better' than monograde but in 30,000 miles on my 350 single I've never had any lubricating issues from using monograde and if it aint broke I don't fix it.

- Some use ATF in the chaincase but I have never had reason to try it.

- Some advise against using Hypoy 90 grade gear oil in the gearbox as it *may* be detrimental to the bushes but I already have mono 50 in the shed for the engine so I use that. Keep it simple.

If you've time to kill have a read of the articles under 'Technical tips' then 'Oil system' in the Technical articles section where you'll find chapter and verse.
Start here:

https://www.jampot.com/article.asp

Thousands of words have been written here and elsewhere on the ins and outs of oil selection but hopefully the above will help for starters.

[MAC]

I must have read heaps of stuff about this subject..wish I'd have seen the post from Spriddler first..best, most straightforward answer I've seen thanks!

[Pharisee]

Like some of the others, I use a straight SAE50 mineral oil in the engines and chaincase of my 3 AMC heavyweights. In the gearboxes, 2 Burman and 1 AMC, I use an EP80w-90 gear oil but make sure that it is to GL-4 spec as this is not detrimental to "yellow" metal in the gearbox.

[RL]

So do I Pharisee and for many years without any problems.

[Ian Heaton]

This is all so helpful - many thanks all.
I think I will go for the monograde 50!
All this help and advise shows the true worth of this forum and the quality of its caring membership!

[Richard Mills]

......and wherever else you use it, don't use a synthetic oil in the chaincase because you will increase the chance of clutch slip.

[MatthewC]

For what it's worth, my 1961 G3 has done around 20000 miles since it had a rebore, I've measured the bore, there's no evident ridge at the top of the bore, which even now is a thou too tight at the top and half a thou too tight at the bottom (which explains why it part seized during running in!). I've only ever used monograde in it, SAE 50 in the summer and SAE 30 in the winter, sometimes from Morris Lubricants and other times from Rock Oil. Their monograde oils do contain detergents, albeit not as much as modern oils, which is fine in a clean engine. Oil changes typically done every 1000 miles, never left more than 2000. It will be interesting to see how the bottom end measures up when I dismantle it further.