This would have been asked before I guess but here goes.
What engine oil seems to work in the TTR ? I had been using a racing 4T (maxima) oil in the XR & never had a problem, been thinking about a semi Syn oil 10w 40, I'm using the same in my Triumph's but they ask for a semi syn oil so I'm using 10w 40 Maxima.
I guess what I'm asking is it worth using the semi Syn in the TTR or just stick with the Maxina 10w 40 4T racing oil ?
On the subject of whether to use mineral oil, semi-synthetic or fully synthetic- it would depend on what you use your bike for and what temperature(s) it operates at.
The viscosity of synthetic oil is thinner than mineral oil and can handle extreme temperatures so is best used when the climate is extremely hot or cold, racing engines or cold starts. It will not break down like mineral oil under extreme temperatures. It also does not break down as quick as mineral oil so slightly longer service schedules can be applied. The downfall to this is that it has a tendency to leak from seals easier than mineral oil (especially with older engines designs).
Semi-synthetic is a mixture of one-third synthetic and two-thirds mineral oil so it speaks for itself (I think).
The viscosity of mineral oil makes it good for break-in procedure, this is because you do not want shavings of metal to ''run around'' in thin oil.
As mentioned though, unless you are racing, operate at extreme temp's or like performance than synthetic is not needed. If you want to use semi-synthetic oil that is your choice. I like to use 15W-50 Castrol Activ mineral oil until fully run in (5-6 oil changes and over 1600 KM)), then change to a fully synthetic like Amsol or Motul in the 10W-30 viscosity rating. The viscosity used all depends on your climate also...
The most important thing to remember is to use the correct viscosity for your climate and riding style . If you live in a hot climate or for hot summers 15 degrees +, 20W-40 is best. On the other hand- if you live in a cold climate 15*~5* (or colder) 10W-30 would be best. The viscosity that you mention i.e.. 10W-40 would be the same viscosity as 10W-30 when cold but once at operating temperature it would remain ''thicker''.
The first digits in 10W-40 (for example) represents the viscosity (thickness) of the oil is when cold and the last digits represents the viscosity when hot. The ''W'' means Winter rated oil.
Another important thing to note is that car oils are made for dry clutch systems and most will contain additives that are not good for wet type clutches. It is best to use a motorcycle oil to be sure i.e.. 4T.
With how developed oil is becoming (mineral and synthetic) it really does not matter what brand or whether you use mineral or synthetic. It all comes down to personal choice, budget and availability whether to use mineral, semi-synthetic or fully synthetic in the end.
My personal favourite is Amsol fully synthetic 10W-30.
Jarrah
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2000 TT-R250M-
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Ported & polished, 73mm bore, Wizeco piston, US header pipe, FMF Q4, #150 main jet, #52.5 pilot jet, throttle stop screw adjusted, larger snorkel, GYT-R air filter, NGK Iridium spark plug, 14/51 gearing, NOS +
