Regulation of iron absorption and transport. Iron for use in synthesis of heme, iron-sulfur centers and other non-heme iron proteins is obtained from the diet and via release of recycled iron from macrophages of the reticuloendothelial system that ingest old and damaged erythrocytes (red blood cells).
Four-stroke oil is more like the oil used in cars but both 2-stroke and 4-stroke oil serve the same purpose - to keep the engine lubricated. Four-stroke dirt bike oil comes in a variety of weights like 10w-40, 20w-50 and so on. It is not mixed with gas.
If you are mostly hitting the sand, go for a bike with plenty of grunt. Soft sand will slow your bike down and make it work twice as hard to get the same kind of speed as you would get on dirt. For someone weighing over 70kgs (154 pounds) I would suggest a 250cc two stroke or something of equivalent power, or more.otocross bikes don't come with a warranty, especially used ones. So, if you're not sure what to look for, here's a USED DIRT BIKE CHECKLIST to help. Some of these things don't cost much to replace. But if the bike has a lot of small faults, the $$ can quickly add up.