Availability of 20w/50 oil

Having trouble trying to get hold of some 20w/50 for me '79 XT500.

There's plenty of the stuff for cars, but i can't seem to get any for a
motorcycle round my neck of the woods (Battersea/Clapham).

Before I go wondering off into the big wide world in search of the stuff,
could someone point in the right direction. Surely there must be someone in
SW London who stocks it! . . . ?

ta
fred

 

I'd just stick car oil in it.

I've run a few bikes on car oil over the years.

 

Use that, then.

 

But isn't that not a very good idea?
I've used car oil in the past and found that after a month of use the oil
gets far too thin after the engine has fully warmed up, resulting in that
gear changes get awkward and clanky. Surely a sign that the oil isn't doing
it's job and friction is getting a grip on things.
If I have to resort to using car oil, will a thicker grade help, and how do
I read the SAE to determine this, ie., if I should be using 20w/50, what
should I look for? And just what do those digits represent?!

thanks in advance
fred
XL250 XT500 CB750F2SS BuellS1WL
www.davidjohnsenior.com
www.davidjohnsenior.freeserve.co.uk

 

If the manual recommends using 20/50[1] then 20/50 car oil is *fine*.
No, it won't **** up your engine (if you used fully synthetic it *might*
cause clitch slip in a wet clutch but then I don't think anybody makes a
fully synthetic 20/50 anyway), and all oil gets thin after an engine has
warmed up, or didn't you notice?

Gear changes are sometimes slicker with clean fresh oil, but if you
think yours degrading as time goes by it's much more likely to be
because the chain needs lubing and/or adjusting.

Using thicker oil is a *bad* idea because it takes much longer to pump
round when cold, so you'll **** the top end of a bike that hasn't got
the strongest top end in the world anyway.

Using a straight monograde 50 will have the same effect, because a 20/50
is designed to flow quicker at cold temperatures than a monograde 50. In
fact, it flows with the weight of a 20 oil, which is what the 20 means.
And the 50 means it flows as a 50 at higher temperatures.

Do a web search on oil designations if you want more info, but that's
all you need to know for the moment because I have the distinct
impression that in your case a little learning is a bloody dangerous
thing for your machinery.

In short, you don't have to "resort" to using car oil. Decent 20/50 is
decent 20/50 and as long as you don't use that atrocious
ukp4.99-for-five-litres shit, you'll be OK. Oil is oil.

No for Christ's sake, don't **** about experimenting with heavier oils
or anything else. Do what you've been told here, don't listen to some
bike shop showroom monkey who may tell you different, and all will be
well.

[1] Almost all bikes use 10/40, but Yamaha's XT/SR500 and XS650 are two
of the rare exceptions, as both use 20/50.

 

The Older Gentleman was seen penning the following ode to ... whatever:

.... or the oil's shit.

Not to mention that it *can* damage the oil pump if the latter is
getting on a bit.

Duckham's Q is something like 5.99 for the gallon can and that's
pretty decent oil. Alternatively there's a Halfrauds 15W50 (probably
too thin) which I've used in the ShiteOldBoxers - they love that
stuff.

.... plus everything BMW made in the last 30-odd years. They sound
*most* unhappy running on 10W40 or 15W40.

 

No, using 20/50 car oil is OK. 20/50 tends not to have all the nasty
friction modifiers that later 'boutique'[1] oils have. Buy Castrol or
Duckhams or Morris or somesuch, just -not- the el cheapo recycled crap that
retails for between 2.99 and 6.99 in B&Q and you'll be OK.

Depends on the mileage and the type of riding. They all do that sir to some
extent.




Surely a sign that the oil isn't

Nope. If the oil wasn't doing its job, you'd find friction would cause a
downward spiral. More friction = more heat. More heat beyond a certain
point means seizure.[2]. If your bike ain't seizing, the oil is working.
There is more to it than that.

NO!. Thicker oil will not flow as well, which may starve the head bearings.
This is a bad thing.




and how

The SAE will give all the info you need. 20/50 describes the grade when cold
and when hot. 20w when cold, 50w when hot. The letters after it determine
whether its designed for compression ignition engines or spark ignition.

Take a trip to Halfords. They used to have a shelfedge that described what
all the letters and numbers mean.

If you are concerned in any way shape or form, go to a bike dealership and
buy oil designated for bikes like Solkolene Pro4, which is a 15/50. It is
about 25ukp for 4 litres.

[1]Some of these 'protects your engine even when you are in the bath' type
oils. Does anyone really fall for the hype?
[2]Yeah, I know thats not strictly true, but you get roughly what I mean
about the spiral of decline when an oil fails.

 

dunno about SW London, haven't lived there for getting on for 20 years, but:

Unipart "Green" 20W50, API SF (IIRC) or
Morris Lubricants "Magnol", API SF

are what the Land Rover V8 gets fed, that being an approx 1970 engine.

The SOBoxer, which is also designed to eat 20W50, either gets that or
Silkolene Racelube semi-synth, which is much more expensive, but better oil.

The cheapo "Motorway", "Formula 1" etc oils as sold by motor factors and
suchlike places for about 4 quid a gallon are only fit for putting in an
engine as an alternative to no oil at all, IMHO.

 

My GS400B uses 20/50 & hated running on 3-star petrol when I couldn't
get any 4-star.

 

I had a GS400, way back when, and 10/40 was recommended for it - as it
was for all the GS Suzukis, IIRC.

 

Aha. As you were.

The HBoL says that 20W/50 is what should be used. This is the book
that I bought shortly after buying the bike and the book that has been
referred to most often.
My more recent acquisition, The Suzuki GS400 Service Manual (part no.
99500-34010-01E), says that I should use ......














....something different....











10W/40

- but it does say that if I don't run the bike in temperatures less
than -10 deg C then 20/50 is an acceptable alternative. So the HBoL
isn't exactly wrong.

 

<faints>

 

Of course i've bloody well noticed, you cheeky so-and-so ;-) I do do me oil
changes when the engines hot for a reason you know.
I was refering to a combination of age and heat. Something that the last
installed car oil didn't seem to handle as well as a bike oil. I assume this
will be due to the car oil not having the neccessary additives to handle the
higher running temperatures and rev's of a bike.

Nope, chain's always looked after well.

Sorry, i was thinking of the oil being thicker when it's hot; refering to
the second set of digits in the SAE. For instance, (and please correct me if
i've got this wrong) a 20/40 oil rather than a 20/50.

Oi, Ref!
Have a word TOG lad, that's a bit below the belt that!
I'm alright with a spanner you know.

I never have done, and I never will do mate.

Yes sir.

cheers though,
fred

 

fred was seen penning the following ode to ... whatever:

Eh? OK, I'm a bit pissed but 20W40 is *thinner* than 20W50 when
hot. It's like:
20W40 - like a monograde 20 oil when cold, monograde 40 when hot
20W50 - 20 when cold, monograde *50* when hot.

As lot as you're staying within the same oil family (i.e. engine
oils), greater numbers indicate thicker oils.

 

Castrol do a car one in a Red 5L bottle, I use that.

I used to think that, until I read up on it!

....

Regards

 

I get Motorworks to post me a gallon of Duckhams Q 20w/50 from time to
time. Turns up on the doorstep. Sorted.

--
Platypus
VN800 Drifter, R80RT
DIAABTCOD#2 GPOTHUF#19
BOTAFOS#6 BOTAFOT#89
BOB#1 SBS#35 ANORAK#18 TWA#15
"WOULD YOU KINDLY SHUT THE **** UP!"

 

Try Fred Warrs in Fulham, or any Harley dealer, they will stock 20/50 oil
for motorcycles.