No...... the numbers 10 - 40 or whatever combination the first number is the viscosity (thichness) in cold or at start up.... the higher number is what the viscosity goes to when it heats up....
So lower the first number better for cold weather it flows better. Higher the second number better it holds together when heated.
I would suggest you go to some sort of syn. oil ..... it takes the heat that you will be generating when you ride hard and the area you are in does not have really cold weather ...
I would suggest Mobil -1 since you can get it most anywhere.... or my choice is Royal Purple... runs about $6/ quart but you do not have to change it everytime ya ride unless you get it to some deep water......
I would also suggest a temp gauge for you oil tank gives you and idea when to back off and let the oil cool a bit .... most concern would be in the sand ... when it will be working the hardest....
Oh with oil filer change just under 2 qts.,.... if you rebuild it will be allmost 2.5 check it then as you do the break in.....
400EX+, 11:1 piston, Hotcam Stage II , K&N w/Outer Wear no lid, Dyna-jet stage 2 w/165 main, Port & Flow, BIG GUN rev limiter, 14t (for sand) 13 tooth (for woods) front 38t rear, Renthal Bars, Barnett clutch, Twist throttle, PEP damper, Full Skid and A-Arm shields, Air Scoops, Shock Wears, HeetSeeker temp Gauge in Oil Tank, A/T 489 23x8x10 & Trailbreakers 22x12.5x8 for Trails, Geko and Shark fins for the sand, Rear brake block off, 42 pilot jet. Installed a 1.5 ton winch.... no more getting stuck ... OH and the Choke fell out....and I added a tether
Never Forget (343) 09.11.01