Oil question not to taxing

[BSA500]

Hi,
 I have been given a couple of cans of oil one is 20/50 which is great as that's what I use.I have also been given some 15/50 does everyone think that would be ok in the A7?.Anyone used it before I was thinking that during winter the lower 15 grade would be ok?
Andy

[MG]

Hello Andy!

Your question IS quite taxing, in fact. Its very hard to give a recommendation here.
I would say it strongly depends on the condition of your engine. If it is freshly rebuilt, within close tolerances, it might be okay. If the clearances in the bearings and the oil pump are rather large already and the engine is leaking oil, things will get worse with the thinner 15W. BSA stated SAE 30 for winter use, which is significantly thicker than 15. I am using 20W50 and find this okay for my rebuilt engines with bearing clearances (main and big ends) of 4/100 to 5/100mm (less than 2 thou). If you want to use the 15W50 it would be a good idea to measure oil pressure, esp. at low revs/idle when warm, just to make sure (maybe fit a gauge instead of the pressure release valve, just for checking when idling?). Oil leaks and wet sumping definitely won't become any better.

[BSA500]

No major oil leaks to speak of(slight weep at the rockerbox).Oil pump was rebuilt a couple of years ago by SRM with a cast iron body,new bearings etc at the same time(old pump let go taking the timing bush with it).Does not wet sump ever now so might be able to use the 15/50 or might just put it in the primary case.I am thinking of fitting a pressure gauge just because they look good and I like gauges.
thanks Andy

[bsa-bill]

Sounds like your engine's in good nick should be ok to run on the 15/50.
You don't say if the 15/50 is synthetic or semi synthetic though, I would have no qualms about using either in my bike but  as you say you have a "couple of cans" I'm not sure I would want to mix it with any other grade of oil, I would say use one or the other but maybe not mixed.

( fiver says this will not be the last post on this subject)   

All the best - Bill

[groily]

Agree with Bill and probably owe him a fiver.
The following's maybe worth a read:
www.upmpg.com.tech_articles/motoroil_viscosity/index.html

[BSA500]

I shall prob use the 15/50 for the primary side and any top ups until I change the engine oil in spring.Might even put some in the forks(I have used 20/50 in the forks before and it seems to work quite well I do not say its a good idea I was strapped for cash and fork oil is dammed expensive).Oh the 15/50 is mineral.
Andy

[MG]

Andy - I'm using a simple and cheap SAE30 for the forks. This is available as lawn mower oil in many places. The damping units were designed for that and most modern fork oils are too thin.

[BSA500]

I tried buying oil from our local lawnmower shops and they were the most expensive(its cause I'm down south and we are very rich!!).I have the double damped conversion and find the 30 is too thick.
Andy

[MG]

Makes sense.
How can lawnmower oil ever be expensive? Must be the worst quality engine oil available. I think mine was about 2 or 3 Euro a litre.

[bsa-bill]

Common practise - just stick something before the word "oil" and up the price, just like A10 stuff on Ebay stick "RGS" somewhere in the description and somebody will pay silly money for it.

Well call me an old cynic if you will 

All the best - Bill

[LJ.]

stick "RGS" somewhere in the description and somebody will pay silly money for it.

Well call me an old cynic if you will  wink

You deserve your fiver Bill... 

[MG]

Yepp, for that perception you deserve a pint of your favourite beer, Bill.
 

Alright, I'm off to sell my A10 crap, ahm, sorry, my precious genuine RGS parts, of course.

Cheers, Markus

[A10Boy]

stick "RGS" somewhere in the description and somebody will pay silly money for it.

I agree, I saw a pair of a10 crankcases which the seller described as "Great for a Rocket Goldstar". I asked him if the engine number had an R after the A10 bit - reply no- so I told him they were not suitable for a RGS. He got quite shirty - dunno why 

You could sell ordinary Petrol pipe. £1.00 / Foot for a goldflash, but call it RGS and you could charge £30 a foot and some prat would buy it.

[rocket man]

as for the lawn mower oil have you tried cutting the grass with your forks mg 

[MG]

rocket man - yep, drained the fork oil on the grass, worked perfectly well, needed no more cutting after a few days