Indian Chief stroker

[s2airflow]

If a Chief is stroked from 74" to 80" is there anything else involved other than changing the flywheels?Thanks.

[R]

Don't the heads also need to be the 80" type ?

[rogerwilko]

Either the barrel height was increased to allow for longer stroke or they raised the gudgeon pin height.

[wetdog]

74in 1200cc boar 82.55mm stroke 112.7mm side valve is this what you have ? and want to go 1340 ?
raised the gudgeon pin height? does not effect stroke , one way is a offset crank pin a common cheat about 7mm for 140cc in this case but they can come lose , make sure you have clearance at bdc for skirt , big boaring some motors can make them slower ie moto guzzi le manns , for more power side valve heads can be worked with good effect

[rogerwilko]

Read what i said again!

[wetdog]

i have , what is your gudgen comment refering to ( compresion height does not effect stroke ) ? indian never made a 1340 as far as i know so what is your point ?

[esometisse]

you definitely cannot stroke a sidevalve engine by simply putting in different flywheels as the piston crowns will hit the combustion chamber roof.
You either have to use longer barrels, shorter connneting rods or pistons with reduced compression height or a combination of all three to counteract the increased stroke.
I think that is what rogerwilko meant.

Cheers
Andy

[wetdog]

i would just pack the barrels , as i know this works as ive done it , no need to change pistons , on ohv engines ( and sv ) this does alter the valve timming in relation to piston position but is to small to be of concern , i am not a fan of this route for power (bhp ) as it does not work , but the sound is lovely

[R]

Indian went 80" for 1950.
80" heads have a recess to allow for the pistons.

[rogerwilko]

Raising the gudgeon pin height on a piston effectively lowers the piston on the rod. Lots of manufacturers do this when stroking engines.

[wetdog]

you can put the pin where you like altering compresion height , but it will not alter the stroke at all , if this is common practice does any one know why they do this ? i might see the benefit with big boar kits ( piston weight etc ) but for a longer stroke i can not , did indian move the pin when they went 80 ?

[rogerwilko]

You're a pain in the arse! Who said anything about gudgeon pin height altering the stroke! Read it again!

[wetdog]

Either the barrel height was increased to allow for longer stroke or they raised the gudgeon pin height........i think that was you ? have you alsymers? i understand 

[Bomber]

Well that reads to me that they either have to lengthen the barrel or raise the pin height to ACCOMODATE a longer stroke, but hey Im just a by-stander

[Revband]

Hey
Come on Wetdog, read all the posts and replies again, then you should understand what Rogerwilco is saying.