2 stroke and gearbox oil

[Peter]

Probably a subject thats been covered before but can anyone please advise on whats the best option for the oils in my AR.
I have a good quality Castrol 4 stroke engine oil 10/40 which I intend to use in the gearbox and a Castrol fully synthetic 2t oil. I used these in my sons KTM SX crosser so would imagine they will be good for the AR.

Any thoughts or advice please.

[knackeredMk1]

You don't neccessarily need 4T engine oil in the gearbox for either bike.

You need an oil specifically for oil injection if you want to keep the autolube.

[Peter]

Anyone recommend what gearbox oil and 2t oil they use in an AR.

[back off road]

real can of worms this one,im sure you will get lots of different replies , i dont own an AR but run a Mk2 on putoline at the minuite ,but may well be going onto pre mix in the not to distant future to allow me to use better quality 2 stroke oil

[Jeram]

AGIP has some well priced gearbox oils, formulated for two strokes...

ranging from racing (change over every race meet), to touring (long milage)

they are cheap and come in just the right volume for a 2T (1L) so they are very affordable compaired to having to buy 4L of crap.




In terms of oil, you have to use a sythetic that is injection approved... but the injection approved oils are pretty terrible compared to the top of the line castor/synthetics.

I ran Fuchs silkoline injection 2T oil in my bike and it ran fine, but its going to run so much better on castor premix once I get her running.

[lgingell]

i use putoline rs 959 - its top of the range (£18 per litre) and is approved for both autolube and pre mix.

as far as gearbox oil goes - i use 10w 40 castrol GPS (semi sythetic) - for no other reason as its the same as we use on almost all road bike 4 strokes - with no problems.

I would advise changing the gear oil as often as you can afford (time and money) to do. the gear oil doesnt really need to be anything fancy, but i believe in using the best 2t available - helps minimize carbon build up on piston / exhaust etc.

[Pie-eyedpiper]

Does the oil for the autolube have to be for injection use? How does it differ from other 2T oils?

[knackeredMk1]

The detail as far as I know it based on some in depth investigation about 20 years ago -

With regards to 2 stroke oil used through an injection system all oil labelled as suitable for injection systems are OK BUT some oils labelled as premix are OK. The problem is the oils that I knew were suitable 20 years ago are not made anymore and the formulation of oils changes over time as well. I use injector oil as I can be certain that this will work.

Most CRM owners use semi-synthetic oil as these seem to be best as synthetic oils tend to need rejetting and are very expensive. I use fully synthetic as I don't use the bike much and I had to rejet as I rebuilt anyway.

[john7780]

i use atf dexIII in my gearbox but i own a tm racing 250 which is quite highly strung especially when im on the track there are quite a few different opinions on gearbox oils but the main opinion that stays the same is if youve done a hard day out on the bike then change the oil

[Jeram]

just found out the following, which contradicts my earlier post in this topic...

all two stroke premix oil including castor/synthetic blends (The best oil you can buy) can be used in oil injection system.

The catch is that is some must be used in a WARM CLIMATE (no, that probably doesn't include European winters for some oils)

as the temperature drops, all oils increase in viscosity to some degree, the oils that are improved for injection are less prone to this effect whereas the castor oil and other non approved products can become very thick, which reduces the volume pumped into the engine for every given revolution.

If you wish to test whether a prospective oil is suitable you can do some simple viscosity tests.
on a cold day (in your climate) put 100ml of injection approved two stroke oil in a small container with a pin hole in the bottom. measure the time taken to drain 100ml of oil.
then while the conditions are the same, clean/dry the container and fill with the TEST oil (perhaps a superior castor/synthetic such as AGIP KART), time how long it takes for 100ml of the TEST oil to drain through the pin hole.

This will give you a RELATIVE comparison of oil viscosity for your region on a COLD day.

if there is a large difference in the drain times I would steer clear of the product and perhaps try another brand of oil.
If the difference is negligible you can most likely run the oil in your bike
If the difference in small but noticeable you could consider increasing the oil pump rate to compensate, this oil pump rate could easily be tested in a number of ways including monitoring fuel/oil consumption.

[Spokey]

[quote="Jeram"]just found out the following, which contradicts my earlier post in this topic...

all two stroke premix oil including castor/synthetic blends (The best oil you can buy) can be used in oil injection system.



Sorry but that is complete B******s ... and a sure way of needing a new piston and rebore.

Autolube oils contain a diluent ( one reason why autolube oils are thinner viscosity than premix oils ) so that when the neat oil is pumped into the carb, it mixes readily with the fuel and provides the proper lubrication by providing an atomised oil / fuel mixture. Premix oils, because these are already mixed with the fuel in the fuel tank and fed in through the same route as the fuel do not need the diluent, so if you tried to use a premix oil in an autolube system, the oil would not atomise properly when injected into the carb so instead of a nice oil / fuel mix - you'd get blobs of thick premix oil in the fuel which wouldn't lubricate properly and likely soon after a seized engine.

You can use autolbe oils in a premix system, but you need to be careful because the diluent in the autolube oil would mean that if you mixed the oil at the same rate as a proper premix oil, you wouldn't get the same amount of oil in the mixture ( hope that makes sense )

Regarding synthetic oils - these will normally always give the best performance ... BUT ... some synthetic oils contain esters, these are very high performance synthetic elements that provide extra protection but these can have their own issues, two stroke oils are designed to be burnt with the fuel, and to burn cleanly leaving few deposits that can block exhausts and such - the problem is that esters ideally need high temperatures to burn off completely, so if you are bimbling along green lanes - the engines may not get hot enough to completely burn the esters off so they can leave sticky deposits ( ask Mazda why they don't recommend synthetic oils for RX-8 engines ) that can stick power valves and piston rings in the worst case - one reason why I always used a good part synthetic in my CRM was that I used it for greenlaning so the part synthetic would not have the ester content so would burn cleaner. If you are using the bike on the road and it gets used properly then full synthetic is fine, but for greenlaning and taking it easy I would suggest a good part synthetic would be better.

One other thing Castor oils and mineral oils DO NOT MIX ( at high temperatures they can turn to a thick jelly / rubber consistency ) ... Castor oils are used for premix oils.

One other thing about premix - premix is ok - but bear in mind how the bike is used - premix is used for competition where you spend most of the time on the gas, and very little time with a shut throttle - shut throttle means no fuel, but also no oil ... so if you are riding on the road, with the autolube system, even when you shut off, the pump will still deliver a little oil into the engine to keep it lubricated, whereas a premix system, you get nothing so if you spend a lot of time with the throttle shut - you are not gettting any oil into it so risk seizing the engine.

Gearbox oils - 4T bike oils are ok because these have been designed to have the correct characteristics for good gear wear protection, but also the right amount of frictional characteristics for wet clutch use. specific 2 stroke oils tend to be an 80W, but a 10W-30 is the nearest multigrade - but shouldn't be a problem using a 10W-40 either. Full synthetic will offer the best protection and performance and for the sake of a couple of quid difference in the price, isn't worth arguing over in my opinion, but part synthetic or mineral is fine also.
ATF fluids, may be ok, but some are friction modified ( Dexron specs ) and are rougly equivalent to an SAE 10 monograde oil and to me that's to thin for a bike box gear box asking for a SAE 30 grade - again for the sake of a few quid is it worth the risk ?

Personal preference comes into it a lot, some have their own preferred brands - buy a bike specific one you won't go far wrong.

Arse ... oil thread , just can't help myself ...

Spokey

[philmedomsley]

I have used Motul 510 2T two stroke oil and Putoline light gear oil synthetic fortified gearbox oil for past two years in both my CRM ARs. Seems to work well with no problems. Not a very technical answer

[garyd]

An engine cannot run on air alone ,therefore when you shut the throttle on a premix bike there MUST be fuel still entering the engine (tickover/slow running circuit)as the oil is mixed with the fuel initially this is why the engines dont sieze due to that theory ,think about it ,if its getting fuel it MUST be getting oil,folk are slap dash with premix that is why they shag engines."ill just put a drop more oil in for better lube"totally the OPPOSITE!!! you have now (by volume ) diluted the fuel ratio towards being too lean ,use the pump .........you know it makes sense

[Spokey]

[quote="garyd"]An engine cannot run on air alone ,therefore when you shut the throttle on a premix bike there MUST be fuel still entering the engine (tickover/slow running circuit)as the oil is mixed with the fuel initially this is why the engines dont sieze due to that theory ,think about it ,if its getting fuel it MUST be getting oil,folk are slap dash with premix that is why they shag engines."ill just put a drop more oil in for better lube"totally the OPPOSITE!!! you have now (by volume ) diluted the fuel ratio towards being too lean ,use the pump .........you know it makes sense[/quote]

True, but you a not getting a lot of fuel and oil , as you say though, use the pump, then assuming it's set up properly, and you a using the right oil, you get exactly the right amount of oil and fuel.

:o)

[garyd]

But ..........you are getting the correct ratio of fuel to oil even on tickover with premix not as lots o folk assume an engine thats about to go bang!But as you quite rightly agreed ,the pump is there to take the guesswork out