Just like a 2-stroke, on the TRX450R (and CRF450/250 dirt bikes) Honda blessed us with tranmission oil that is seperated from the engine oil! While you can run plain old engine oil in the trans, that just doesn't make much sense when you can instead run a trans specific oil that is pumped up with extra high pressure, anti-shear, and anti-foam additives that plain engine oil just can't have.

So, I am trying to select a transmission specific oil, and decide what weight is most appropriate for a variety of conditions. My 450 is strictly a desert cross-country machine. In So. Calif., that means it gets ridden mostly in the winter, and sits in the garage all summer when the deserts are over 100 degrees F. In winter, the deserts are a land of extremes! It can be 90 degrees F one day, and snow the next. It can be dry for months, then you can have a rain and flash floods. On average, I would say that it is 40-60 degrees F at night, and 60-80 degrees F during the day. But, it can go below freezing, and it can be as high as 90 degrees F as well.

Honda's own trans oil is 80W/85W (http://powersports.honda.com/the_goo...?TheGoodsDir=0). My preference so far has been Maxima which comes in 75W "Light Weight", 80W "Racing", or 85W "Endurance" (http://www.maximausa.com/products/gearlubes/mtl.asp). Other choices might be Klotz (http://www.klotzlube.com/storeCats.asp?ci=4), or Motul (http://www.motul.com/uk/produits/index.html).

One thing that most people don't know is that gear oils use a completely different system of weights (which represents viscosity) from engine oils (http://www.maximausa.com/technical/l...s/spring98.pdf). So, an 85W trans oil will have the same viscosity as a 30W engine oil. An 80W trans oil is like a 20W engine oil, and a 75W trans oils is like a 10W engine oil.

So, my dilema is which weight to run??? My thought was to run 85W trans oil in warm weather, and 75 or 80W in the cold. But, if 75 and 80W trans oil are like 10 and 20W engine oil, isn't that awfully thin??? I would never ever run a 10 or 20W engine oil, even in very cold weather (owners manual recommends 5W30 engine oil for the coldest weather). If I ran 75W trans oil one day when it is freezing, that would be totally inappropriate for the next day when it might be 90 degrees F!

 

Found this reference from Tom Morgan Racing (http://www.tommorganracing.com/produ...mendation.html) where he is recommending a Redline product (http://www.redlineoil.com/).

It seems to me the applications for a motocross machine are different from that of a desert machine. An MX bike gets a few quick laps, then it gets parked and cooled down, where a desert bike gets ridden long distances at high speed. In MX, it pays to have a fairly thin oil that isn't going to cause much drag, but in desert you have more of an endurance application.

For my application, I think I difinitely need something that is MULTI VISCOSITY, and will therefore cover a wide range of temperatures.

 

I've ridden with 3 guys with 450r's for almost 2 years now and they just use the regular honda 10w-40 HP4 motor oil in the tranny. All have hundreds of hours on them, all are cammed and piped, and there hasn't been one clutch or tranny failure yet.

 

While engine oil works, it isn't taking complete advantage of the advantages Honda provides by seperating the engine and trans oils! Like most things in life, there are many choices, and each has its up sides and down sides. Some choices are ok, some good, and others better. I always look for better, when I can find it that is.

Your buddies probably went for the convenience of using the same oil in the engine and trans. But, your friends are running 40 weight, and from all the research I have done I find that a trans is meant to run at a lower viscosity. Something more like 30, 20, or even 10 weight.

I use to think that those big numbers on gear oil bottles meant that it was THICKER! I thought that 80 weight meant that it was twice as thick as 40 weight, or something like that. Then I bought a bottle of Honda trans oil for my 450R, and discovered that it wasn't thicker at all!

 

I have ran the Honda Semi Synthetic in my 250R for years. Lately I have had clutch problems and they have never lasted like they should. I switched to VP MTF1 < since I work for them, and it cured alot of problems. I strongly suggest it and havent talked to anyone yet that is disappointed!