Petrol/oil mixture

[Robinson87]

Can anyone advise me what petrol/oil mixture they would recommend I run my 1959 scottish 24tas at, (250cc 32a engine) and I'm using castrol R,
I can't live with out that classic smell of R. It seems I'm not the only one .when ever it's running a crowd seems to gathers at the end of the exhaust.

[Colin Sparrow]

The factory recommended 16:1. You should be OK on 25:1 if you're not going to thrash it. Modern mineral or synthetic oils allow higher ratios these days.

[Brian Catt]

The originator was querying the ratio for Castrol R, but this is probably not the best oil to use. As per Colin and John's recommendations, modern oils are better, but a spoon of R will add to the aroma!!!!
The ratio for the modern oils is much thinner, so the bike will be less smokey, but it depends if you are Metric or Imperial! Metric people will go for 25:1 (40 cc in 1 litre) while the died in the wool Imperialists will go for 24:1 (1/3 pint per gallon). This ratio should be quite OK for Trials and Trail use, but may need upping if you want to use it as a racer!

[Colin Sparrow]

Racing synthetic premix smells pretty good when burnt in a 3T...

[dave higgins]

Brian, adding a spoonfull of r, whilst running on a mineral or synthetic variant will also add a little something extra to the repair bill...
Castor oil cannot be mixed in any quantities, with other types of oil, putoline do a synthetic race oil with the great smell of r though...
But going back to the start, as colin said 25-1 is plenty, but don`t leave it in the tank to long, as r will deteriotate.

[Brian Catt]

Dave, I have seen the wise words somewhere that as long as the R is burnt in combustion, it won't harm the lubricating properties of the base oil, It's only when they get mixed at high temperatures in flow that you get nasty consequences. I must admit I have no proof either way, but I can recall people telling me they add R to their normal mix in very small quantities.

[dave higgins]

Can`t see that, because what you call, your base oil is being fed in the same way, you may be getting confused with fourstrokes where by there is a separation of oil & fuel to a degree.
But no worries as the guy is running on r anyway, & it was only someone else trying to change the thread that got us here..

[John Wakefield]

I dont always agree with you Dave but your advice on this subject is bang on correct. Do not under any circumstance mix Castor based oil with mineral or synthetic in a TWO STROKE. Also if changing over from R to other types of oil flush the crankcase through with neat petrol.

[John Wakefield]

Can anyone advise me what petrol/oil mixture they would recommend I run my 1959 scottish 24tas at, (250cc 32a engine) and I'm using castrol R,
I can't live with out that classic smell of R. It seems I'm not the only one .when ever it's running a crowd seems to gathers at the end of the exhaust.

As the Scottish engine is lightly stressed it would be better to change to a good quality mineral based oil such as Comma Two Stroke ( I have used this for 15 years in a 4T twin with no trouble) http://www.commaoil.co.uk/productsguide/view/6/267
This can be left in the tank & will not deteriorate like R which should (as Dave says) be drained off when bike is not used. Ok with a scrambler but not in a road going bike.

Note I deleted my original posting as I had not read Robinson87's posting correctly. This leaves the thread a bit disjointed

[Robinson87]

I would just like to thank everyone for their replies, my heart is ruling my head and will be staying on Castrol R.
Fresh mix will now be mixed each time the machine goes out and I will drain the tank if its stored for any length of time. At the moment I do not use it in competitions , just for very light use. If I do decide to compete the machine , I will probably change to a semi-synthetic oil.

[dave higgins]

Stick with r40, pound for pound, its still the hardest working racing oil available...

[Colin Sparrow]

Doesn't it make a mess if it gets baked on though!

[Rob]

My turn! Use a fully-synthetic racing oil such as Silkolene Pro 2. Just the same as with Castrol 747 it contains a small amount of castor content anyway. Run this at 50:1 with a small drop of R for the smell effect!

I thrash my Anglian in trials using any fuel I have left over from my racing Yams and it hasn't blown up yet!

The Yams run on 32:1 747 with 50/50 V Power and avgas. One of them is fitted with Hans Hummel barrels to GP spec and produces a lot of bhp. If that runs fine on 32:1, I'm sure an iron barrel Villiers will!

If in doubt, keep increasing the oil until it stops seizing!!

[Mike48]

I've been using Silkolene Pro2 Kart in the Villiers iron barrel engine since rebuild, in daytime temperatures of over 30 selsius. It has been clean burning - even at 25/1. Though I wish the smell was more Castrol R - I might have to add a few drops as well.
Mike

[pgc40]

premix for villier engines

I tried 30:1 and my 37A seized when it overheated so now I use 25:1 premix but should I be using 20:1?

I found this comment on the Villiers forum interesting.

Two-Stroke Oil Premix Ratios

The following is extracted from the Villiers forum, and is applicable to most twostrokes built before the mid-1960s.
As far as premix goes the 16:1 is still correct for running in a new engine and you can then cut down to 20:1 thereafter. Villiers began to recommend 20:1 in the early 1950's when self mixing two-stroke oil first became available. This is appropriate for both the engines you have . You will be told you can cut down the oil a lot if you use a modern synthetic oil. Do not do so. Synthetic oils are meant for modern two-strokes designed to modern standards. The older design of Villiers engines means they need a lot more oil. They are the last of the early design of two-stroke, for best results stick to 20:1. Because they are a slow revving engine compared to later two-strokes a two-stroke oil suitable for lawnmowers, chainsaws, etc, is fine for them. It will smoke when it is cold, it will smoke if you only travel short distances but it will stop smoking when it is hot and stop smoking if you ride it any distance. If a pre-mix two-stroke is smoky all the time its the riders fault not the bike. It is not being ridden far enough or long enough to keep clean. For years I rode two-strokes to work and they would get smoky in all the stop/start traffic. When it got too bad I would go for a fast ride on the local freeway which would clear the exhaust of the oily build up. The bike would then run sweetly for another month or so and I would then repeat the exercise.

If you had an old bike with an ordinary four-stroke engine and someone told you it would run better if you only half filled it with oil you'd think they were nuts. Cutting down on the oil in premix is exactly the same thing and just as foolish.

Do not bother with premium grade fuel. Again, because these engines were designed in the days of low octane fuel there is no point in using anything up market. Standard unleaded fuel of today is far better than anything available when they were new. Also, they are unable to take advantage of anything better so it is just a waste of money and you won't get any better performance. Always use unleaded. Leaded fuels can quickly foul up the spark plugs on Villiers engines and be a real nuisance. The introduction of unleaded fuel was a real bonus for two-stroke riders as it got rid of a lot of spark plug problems.

by 33d6