anyone wana explain

[hudack]

ok so read this then someone explain it to me pros cons how it would work im interested in reading more about it

ive always wanted to do a 64mm bore and run banshee pistons with a +4mm crank setup,resleeve the cylinder with an aluminum liner and plate it.That would be a nice combo for MX racing

why would you want to go to a smaller pistion ?????????????????????

That would be awesome!!!!!


To have a more square bore/stroke combo.

 

[blasterracer817]

the added stroke takes up for the ccs gained by the piston, it would give yoy an almost equil bore to stroke which is what is hot in mx, plus the added stroke is good down low and it would keep you in 200cc class and the aluminum and nikisal lining is also for better cooling

 

[Awk08]

apparently that is to get the bore size close or equal to the stroke measurement, which i believe is said to be the ideal motor ????,
anyone know if any bikes/quads that have a "square motor" ??

 

[blasterracer817]

the zilla 86x86=500cc, otherwise its mostly stroke over bore, IE yz 80 125 250, cr 80 85 125 250 trx 250r lt 250r etc

 

[79 bronco]

For a MX racing you can have up to 200cc in the blaster class, so you cant go with a BB or stroker.. So running a 64mm bore and +4mm crank setup you will stay under 200cc and have a square motor... stock is 66x57 and with a 64mm bore and +4mm crank you have 64x 61 that is more square...

The 1983 to 1998 yz, it, wr 250 are 68x68 square....

The motor in my bronco was square 4.00" x 4.00" but now its .040over...lol

 

[sheeblast]

stroke > bore, usually more low end power
stroke = bore, good all around power
stroke < bore, high revving power

 

[hudack]

thanks for clearing that up so basicly it would be more tq ???

 

[blasterracer817]

yes you got er \m/

 

[sheeblast]

thanks for clearing that up so basicly it would be more tq ???

ok this is a huge misunderstanding. more torque does not mean more low end power. and more horsepower doesn't mean more top end power.

 

[motoman9911]

I know for higher rpms you want a shorter stroke. Look at F1 cars.

 

[hudack]

i thought more torque meant better acceleration and that a bigger crank gave you more torque ???

 

[blasterracer817]

sheeblast is right on the tq doesn't always mean more bottom end, but thats the way most people look at it, so thats why i said yes hudacks right, and motoman your correct with the shorter stroke means higher rpm, thats why the roadracers like the oldyamaha f2 where 2 cyl 250s super short stroke with ok size pistons, but could spin 11000rpm stock all day long

 

[sheeblast]

yes it will increase torque, but low rpm torque. a longer stroke decrease the "overrev" of an engine. same with compression.

 

[lowkhalbalr]

i thought more torque meant better acceleration and that a bigger crank gave you more torque ???

thats a catch22 you can alsoo pick up torque from rpm, dependant of course upon gear ratio.

 

[OConnor Racing]

Can you buy an aluminum sleeve? I've heard about Sean Snyder doing this. Not sure what he used for sleeve material.

 

[CHutzell]

just give la sleeve a call they can make you one,last time i checked into it they were asking 200$ per sleeve but that was years ago,im sure cost has gone up since then.
There would be abit of $$$ wrapped up in just a topend and crankshaft with the sleeve and the plating ect.but it would produce some very good power.

 

[Kgibson]

Ya Snyder, hetrick and a few others run this setup. A local bike has it and it is fast...mine's faster :}