BelRay 10w fork oil works good. Using a 10w-30 in a fork is like using a straight 10w because the second number refers to the acting-weight/viscosity at engine operating temps. The forks do not appreciably heat the oil so it just acts like the base-weight oil (e.g. the 10w in a 10w-30 oil).
The shop manual for my bike says the fluid capacity for the right fork is 23.5 oz. (US). I poured that much in, worked the outer tube and damper a number of times, then measured the height of the oil column, and found that it was more than an inch high. So I sucked the oil out to bring it back into spec (4.1 inches from the top of the fork).
I've searched around the forum here and it seems to be confusions about fork oil recommended in the Honda manual that clearly states Fork oil SAE 10W-30, 220-230cc (7,0-7,3 ozs) in each leg. Some use engine oil that is lubrication oil. I can understand that ATF or Hydraulic fluid might be an alternative to fork oil Motorex has fork oil 10W-30
Drain the extra oil from the oil holes (12) of the 2. Tighten the fork center bolt lock nut (2) fully Fork Assembly and measure the thread length (A) as shown. fork damper oil chamber (5). Standard: 11 – Page 129 Front Suspension Adjustments 3. Install the collar (3) to the C-ring (4) of the fork 4. Blow out the oil completely off the fork Posted April 18, 2012. My Rides (6) The manual calls for 10w oil filled to 5.7" from the top. I recommend bringing the oil level to 5.5" by adding 10cc (1/3 oz) to each fork leg to prevent bottoming on bigger hits. I use RT emulators in my CRF230F but I used 10w with one BBR spring prior and it worked great. When I setup other CRF230Fs I do the QgEJ.