stroking an engine?

[400exJOE]

I have heard the term stroking an engine many times and don't know what it means. Does it have something to do with adding displacement? If so, how? What is a stroker?

[Wheelie]

A stroker essentially means you're increasing the distance the piston is traveling up and down in the cylinder, therefore increasing displacement.

A stroker requires a new crankshaft with a longer throw, a shorter rod, OR a modified piston. Case machining usually goes along with it as well to make room for the new crankshaft.

[MxStar826]

You really are stupid Joe.Why dont you get a real quad and modify it?Like a Lt250R.

[Chef]

a real quad, and you say an LT250R? not bad mouthing LT250Rs, but i know that they werent that great...

[MxStar826]

Ya,true,but i bet u could but half the amount of money you would in to a 400ex in a Lt250r,and the Lt would still smoke it.




-Nick-

nick im gonna show you how fast your LT is when i smoke you on a blaster. As for joe hes got something instore for you and your not gonna see anything but dust.

[MxStar826]

Craig,if i got beat by a blaster on a 250 i'd personally kick my own ***.hows that?

you wont be able to find your *** with all the dust in your face. so if you want ill do it for ya.

[400exRacerX]

Originally posted by Wheelie
A stroker essentially means you're increasing the distance the piston is traveling up and down in the cylinder.

A stroker increases the distance the piston travels downward. It increases the amount of downward travel, if it increased upward travel your piston would be hitting your valves and spark plug.

[MichaelS693]

i agree with racer X

[400exJOE]

my 400ex already beats lt250rs. I beat one in a drag and now i am getting a 440. Have fun chewing dust. Get on ur suzook and ride out of here.

mxstar826 do me a favor and go to the bottom of the page and read the rules of this webpage,,we don't allow snot nosed kids to come out here and start bashing people,,thanks.

[Wheelie]

Correct me if I'm wrong---If the piston is traveling farther down, then it's traveling farther up. In order to achieve a stroker, the journal of the crankshaft is farther offset--correct?

If the engine builder is stroking a quad 4.5mm, the crankshaft journal is 2.25mm farther from the center, therefore moving 2.25mm farther UP in the cylinder. That's where the shorter rod, or modified piston (the wrist pin location is moved higher in the piston) comes into play. The modified piston would be more ideal to keep the rod/stroke ratio better. A longer stroke with a shorter rod will be hard on piston skirts and cylinders.

Then again I could be wrong.....

Wheelie is correct. in order to get a stroker you need a longer stroke on the crank, the rod journal is farther away from the crank centerline. Distance increased going down is also increased going up. And yes it is better to get a special piston to prolong the time/duration the pistion stays at TDC.

[barbwire44]

A stroker could be either way it could be a longer rod stroke or a shorter rod stroke. A long stroke usually increases power, and a shorter stroke usually revs quicker.:D

true Barb but that would be a de-stroked engine. like turning a 400sbc into a 377. It is common to refer to a stroker as increasing displacemnet by increasing the throw of the crank