How much oil do I put in the transmission on a CRF 450 2006,

the two side....honda is the only compagny that used separate transmission and engine oil (crf 250 and crf 450). the left side is the engine oil and the right side is the transmission. i recommend 5100 motul on the engine and motul 3000 10w40 on the transmission side (motul 3000 is not a transmission oil but it works on fourstroke that normally mix it up to getter ) d,ont forget to replace filter ....hope this will help,if so ....leave me good feedback please.

The crankcase oil fill is the dipstick hole on the left side of the engine. It holds .73 quart. The right side fill plug is for the transmission oil. It holds .63 quart. You will need to drain the transmission oil and refill it with the correct amount of oil. The drain is located on the left lower crankcase. It is bolt/washer in the parts diagram of the link below. I recommend you purchase an owners manual or service manual for this bike as this is a high performance model that requires frequent maintenance.
http://216.37.204.206/wps/Honda_OEM/HondaDB.asp?Type=12&A=1

Hi Niven

There are also 2 separate drains/fillers one for the transmission and the othe for the crankcase . The measure is 620 ml per side, although some guys run up to 700 ml on the transmission. 10W-40 is the correct weight for the engine side. On the trans side a Transmission specific oil in an 80W or 85W grade. Maxima Extra full synthetic is the best oil you can buy for the engine. Maxima MTL is the best for transmissions.

regards
robotek