The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: pjm01 on 08.07. 2012 12:20
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After 40 odd years I have returned to 2 wheels (1959 Shooting Star) and am confused by the amount of info. regarding oil type for the engine/gearbox/chaincase. The (old) manual states SAE 40 (which I have found difficult to obtain locally/Ipswich), for all 3 applications.
Haynes manual states SAE 30 for engine, SAE 50 for gearbox and SAE 20 for chaincase.
Another BSA owner suggests 20W50 for engine, SAE 50 for gearbox and 'something really heavy' for chaincase to prevent/cure leaks.
Yet another opinion was 20W50 for everything .......
Is there a 'correct answer' or are all the above answers equally right/wrong ?
Baffled of Ipswich (Peter M)
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Oh goody an OIL thread.
As you have guessed already it is really a case of "whatever floats your boat"
Any oil now days ( ever supermarket oil ) would be better than what was available when the bike was new.
Oil is about the only thing where BSA riders actually seem not to be terrified to open their wallets and lot of blokes run really expensive oils
Now FWIW I use 20w50 in all my BSA's in fact I use 20w50 in every thing, lawnmowers, motorcycles & vans.
Thus I have only 1 grade of oil to worry about, no chance of getting it wrong and to date nothing has blown up.
The most important thing is you change it very regularly which is why I use cheap oil ( I buy it in 44's from the local refineary )
Way back I used BP coarse + ( 30 , 40 or 50 )
Then Penrite HPR 30w40 or 40w50
Then Valvoline 20w50
And now Marifine 20w50.
If you want to be selective you can go for Auto trans fluid in primary ( pink ) and a special manual gerabox oil ( purple or bright green ) and then whatever engine oil you please in the motor thus you can determine where it is leaking b the colour of the fluid under the bike.
50 weight gearbox oil is about the same as 30 engine oil as they are measured on different scales.
Just remember that heavy oil in the primary will seriously knock off the horsies and heavy oil in the gear box will make the changes really slow ( as well as knocking off some horsies )
Down here a lot of pre- war riders use liquid grease in their boxes as there are no oil seals and most of the cases are worn quite oval by now
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You could get 100 replies to this post with 100 different recommendations, thats how it is when the "OIL" subject rears its head.
I run a 25-50 multigrade in my engine and primary and 80-90 gear oil in the gearbox.
If you use engine oil in your primary make sure it is a "motorcycle only" oil, car engine oils have friction modifiers in them that can affect motorcycle clutch plates.
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Hi. I,m back to biking again after nearly 30 years, and things have changed in most area,s, please find my choice of oils.
Engine oil 15w/50 Morris
Gearbox oil EP80/90 Morris
Fork oil 20WT Morris
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Just seen this topic. When I rebuilt mine I asked SRM for some advice. Straight 40 for cold weather straight 50 for warm was the answer.
Modern multi grades suspend crud asuming there is a filter in the line to take it out. Mono grades don't suspend and therefore don't carry it round the engine.
If you have fitted an inline filter then modern multigrades are ok I believe.
Best tip, change it real regular.
Regards Huddie
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Whether an oil is multi or single grade does not affect its ability to suspend crud or not. The ability to suspend the crud in circulation is determined by the detergent properties of the oil, low or nil detergent oils allow the crud to drop out into the sludge trap or the bottom of the oil tank as per the original BSA design. High detergent oils keep the crud in suspense until it hits a filter. So as soon as you fit a filter you need a high detergent oil which will keep the crud in the oil for the filter to retain leaving you with a clean sludge trap and a clean oil tank. If you don't fit a filter you need to change that oil regular and clean out that oil tank bottom every oil change so the minimum of crud gets to the sludge trap.
Considering the low cost of a Norton filter head and filter there is no reason not to fit one and join the modern world with a high detergent oil.
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Well spoken Kommando,
As I re-read Huddies post, I was thinking multi-grade doesn't necessarily mean detergent, like what you said, then read yours.
Now which part of SF/SS/FF/CC.....whatever, if any, determines detergent quotient??
Cheers, duTch
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Good advice Kommando.
and once again I'll state - one of the first if not the first 20/50 (Duckhams - the green one) was designed for motorcycle engines of the day, early sixties, and they had for the most part no filters as we think of them now.
It was also credited with preventing the cream gunge found in engine rocker boxes (specially the Mini), personally I never found it made any difference to this at all. *dunno*
As has been said many times before regular oil change 1000/1500 miles or yearly whatever comes first, and you might as well use a cheap oil unless you can convince yourself of some benefit for the extra cost over the time scale --- perhaps sleep better on an empty wallet *sleepy*
Hi Dutch you beat me to the button, I'll add to your comment re detergent that many straight oils do contain detergent, including the so called Classic oils
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Having had earlier problems with wet sumping using 20/50 I now use a straight 40 for the motor all year round without issues. I buy on line - and use Silkolene Chatsworth. This has detergents, and I am using a return side filter. I change the oil every 1k miles regardless. Chaincase currently runs ATF, and I think the g/box has something around 80 or 90; I don't look in there too regularly.
My oil filter arrangement came from Paul Goff and resides in the tool box. It takes 2CV filters. I drain the filter at every oil change and swap it out every other change.