engine stroke

[GTi_Leo]

is the stock 30cc really a 28mm stroke? by my calculations if its only a 28 stroke and 36 mm bore its only 28.5 cc or is it a 30mm stroke.


reason I ask is because I bought a 4 bolt 30.5cc king motors head and crank case and want to use the stock HY crank and piston

 

[phreerider]

30.5 cc is (28) +2

heres an open case on 30.5cc and the +2mm stroke



http://www.redcatrampageforum.com/showthread.php?t=12944&page=6

 

[GTi_Leo]

I know that a normal 30.5 CY or Zenoah is 28+2mm for a 30mm stroke but is the stock HY crank the same. I ask because I don't want to put it in and have useless compression because there is 2mm less travel and more space to reduce the compression

 

[phreerider]

HY 30.5cc is same as CY and Zen, they all make displacement in same fashion.

 

[alfred e numan]

long rod verses stroker cranks.

hi. here i am sorta - kinda off topic --- agan. the cranks we use from the factories are not stroker cranks. they are long rod cranks-- the 30 mm ones. what does a long rod crank do to the approate - correct cyclnder matched for a long rod crank? A long rod crank enables to spend more time before & after top dead center. same story at bbdc & after bdc. slower reving motor-- but this enables it to build power by increasing the amount of time the engine has to pull in fuel mix. but you guys allready knew this--- db

 

[GTi_Leo]

would anyone have an extra 30cc crank I can buy off them thinking of building both motors up, the HY really seems to be a built of solid construction, even as a 2 bolt