I dont get this. The book says 10 40 in the trans side, and the techs at the local dealer swear that 80w85 is the way to go. What do you guys run. I race XC on this thing and beat the crap out of it, so I want it right. Thanks in advance

 

The big advantage of using a (2-stroke type) trans specific oil, is that it contains huge amounts of high pressure additives to protect your gears, that a motor oil won't contain! Start by reading this great article. All the info about the CRF 250/450, also goes for your TRX450R:

http://www.thumpertalk.com/

Red Pro Honda HP Trans Oil is one of the oils recommended in your owners manual (see page 93). You can also run a motorcycle specific engine oil as long as it is API SG/JASO MA. I would for sure use Honda Trans Oil before I would ever use either Honda GN4 or HP4 (without moly) engine oils. Maxima MTL is also an excellent trans oil, and I would personally choose it over the Honda Trans Oil!

Where the confustion comes, is that people don't understant that TRANS OILS AND ENGINE OILS USE A DIFFERENT SYSTEM FOR RATING VISCOSITY! An 80/85 weight trans oil, actually has the viscosity of an SAE 20/30 weight engine oil, when it gets hot. People think it is going to be to THICK because it says 80 weight, but it uses a completely different system:

http://www.bobistheoilguy.com/visc.html

Personally, I run Maxima Extra ester based synthetic engine oil (API SG/JASO MA) in both my engine and transmission sides. I prefer the high ester content in the transmission, as esters have very high "high sheer" values, and stand up to a transmission better than petroleum products. My second choice would be Maxima MTL.

http://www.maximausa.com/products/4s...synthextra.asp

http://www.maximausa.com/products/gearlubes/mtl.asp

What oil are your running in your engine side????

 

I run Pro Honda GN4 10W40 in the engine side, and change it very frequently due to the fact that I race 2 hour harescrambles about twice a month, and ride several times a week. I changed the trans oil and put the HP4 in, and it seems to fade a little less after a long, hard ride or race. Think I should do something else in the engine side?

 

Honda GN4 is just basic old petroleum oil, and frankly I don't think it is up to lubing a screaming 450R! Honda HP4 or HP4M (with moly) blends are fortified with synthetics, so should be somewhat better. Moly is great stuff for your engine side, but don't use HP4M in your trans side.

I ran Honda oils years ago, but no longer use them since they have been downgraded from API SG to SJ (probably an economic descision???). In the dirt bike forums, those that run Honda oils in their 450 engine sides, are reporting that they are burning lots of oil. Presumably, it is slipping past the rings (????).

If any engine can benefit from a synthetic, it is the new generation of screaming 250/450's. Like I said, I prefer the ester synthetics for a bunch of reasons: http://www.maximausa.com/technical/l...beNews2002.pdf