See the oil table in your owner's manual, for outside air temp vs weight of oil. For Honda's, usually 10W40 for hot weather, and 10W30 for mild weather. For winter, 5W30 or for extreme cold 0W30. For break-in oil, I use Maxima Premium. It is just a plain old basic petroleum oil. I would probably use Honda GN4 if I couldn't find Maxima.

Some oil reading:

ThumperFaq: 4-Stroke Oil

Oils Well That Ends Well, Part 1 - Sport Rider Magazine

http://www.maximausa.com/technical/l...beNews2002.pdf

The ester based oils are the best! If I am using 10W40 or 10W30, I run Redline. If 5W30 I run Maixma 530MX, or 0W30 then Maxima Ultra. If you can't bring yourself to pay for an ester, then just find some Maxima Premium. Maxima has the best additive package in the business!

 

k, thanks for the oil info! just took the 400ex for the first ride this weekend and love it. definately gona take some gettin used to before rippin it around much, but man it is so much funner to ride. cuple more questions tho:

first, my dealer told me not to run synthetic oils because it can make the clutch slip, any opinions on that?

second, i heard that adding ANY aftermarket parts or oils to my atv will void the 1 year warantee, such as engine oils, air filters, etc. is this true? i dont think i can wait that long

 

1. Synthetic oils are much better (clutch included) as long as they are Jaso MA rated. Do not buy oil for your bike without that rating.

2. Read the warrenty and find out.

 

k, thanks!

 

The thing you want to look for regarding synthetic oils is that they are not of the "energy conserving" type. These energy conserving oils have moly in them, which is what causes clutch slippage.

 

I did a early oil change on mine using a Honda filter and the gn4 10w-40 oil,I may go with Valvoline ATV oil which is a on the shelf product at my local parts stores seeing the Honda dealership is a hour away and it meets the specs ,I've changed alot of other local riders oil using it with no issues

 

k, well ill jst use dealer oils/filter then...

also, has anyone had overheating problems with the 400ex, seeing as it has no radiator and just an oil cooler? i live in central florida which can get VERY dry at times during the summer and temps up around 100* F and sometimes higher. if there is a risk, then i want to get a temp gauge.