could anyone please tell me what the caster effect is?or some links that give a good explanation?
Sorry, man, but I don't understand the question. I've never heard of the 'caster effect', unless you're referring to the tendency of a castor (wheel) to align itself with the direction of travel. That is based upon the centre of thrust being offset from the axle of the wheel.
Try a web search for automobile caster.
Caster effect occurs when the point of contact is offset from the pivot axis, like a wheel on a shopping cart. The wheel will align itself to the direction of travel, because if it's sideways, there's a torque force created that straigthens out the wheel.
In the case of motorcycles, the distance between the contact point and where the axis would intersect the pavement is called "trail".
You might have more fruitful searches if you type "castor" instead of "caster".
The spelling seems to be pretty ambiguous, but most of the sources I've ever used use 'castor'.
No, it's caster with an e. Castor is a type of oil.
And caster is a type of sugar!
My dictionaries (Cambridge, and Collins (and also, Dictionary.com!)) give either spelling as valid (when dealing with small wheels, or the effect in question). I was just suggesting trying a different spelling for searching purposes!
Separate names with a comma.