who has a ?

[400exshop]

Who on here has a 440 stroker ? Not 460-465 what i mean is.
It's a 426 with a 4mill crank. What i need to know is where do you get the pistion from ? I have found a 440 pistion for the 4mill crank. But i can find a 426 pistion for the 4mill crank.

Thanks 400exshop ( aka ) Eric

[bherriman]

a 440 stroker is made possible with an 87mm (416) bore and a 4 mm crank. Powroll makes a a whole kit.

[400exshop]

416 ? that dont add up 426 with a 4mill should be the 440 stroker. Maybe a 416 with a 7mill crank. Now that may make a 440 stroker. But thanks for the info. Any one eles ?

[bherriman]

This is taken directly from the Powroll website.


http://www.powroll.com/P_HONDA_TRX400EX.htm




STROKER +4.0mm WITH ‘TOUGH ROD’

SHORT ROD - USE ANY 400EX PISTON!

425cc with stock piston, 440cc with 87mm piston, 460cc with 89mm piston

Stroker only, piston kit not included.

This stroker utilizes our super-strong Falicon-built ‘Tough Rod’ (with your stock pin and needle assembly).

The shorter rod allows you to utilize any 400EX piston kit (piston skirt may need to be shortened with brands other than Powroll) and does not require any case or gear modifications.

INCLUDES: New Powroll Tough Rod. Stroke work done on your crank.

REQUIRES: Your crank pin and needle assembly must be good. Non-Powroll pistons will need modification to skirt. Send in your crank for modification. Download our Stroker Booklet for details


Does it add up yet?

[ish416]

Here is the maths for those interested.

Stock bore is 85mm, stock stroke is 70mm.

.7854 x 85mm x 85mm x 70mm = 397216

Divide by 1000 = 397.2cc

Stock bore + 4mm stroke =
.7854 x 85mm x 85mm x 74mm = 419914

Divide that by 1000 = 419.9cc

A +4mm stroke and 87mm (416) piston =

.7854 x 87mm x 87mm x 74mm= 439907

Divided by 1000 = 439.9cc

A +4mm stroke and 88mm (426) piston =

.7854 x 88mm x 88mm x 74mm =450078

Divided by 1000 = 450cc

[PaRedneckRiders]

Originally posted by ish416
Here is the maths for those interested.

Stock bore is 85mm, stock stroke is 70mm.

.7854 x 85mm x 85mm x 70mm = 397216

Divide by 1000 = 397.2cc

Stock bore + 4mm stroke =
.7854 x 85mm x 85mm x 74mm = 419914

Divide that by 1000 = 419.9cc

A +4mm stroke and 87mm (416) piston =

.7854 x 87mm x 87mm x 74mm= 439907

Divided by 1000 = 439.9cc

A +4mm stroke and 88mm (426) piston =

.7854 x 88mm x 88mm x 74mm =450078

Divided by 1000 = 450cc

Yep thats it.

[atv fan 28]

Originally posted by ish416
Here is the maths for those interested.

Stock bore is 85mm, stock stroke is 70mm.

.7854 x 85mm x 85mm x 70mm = 397216

Divide by 1000 = 397.2cc

Stock bore + 4mm stroke =
.7854 x 85mm x 85mm x 74mm = 419914

Divide that by 1000 = 419.9cc

A +4mm stroke and 87mm (416) piston =

.7854 x 87mm x 87mm x 74mm= 439907

Divided by 1000 = 439.9cc

A +4mm stroke and 88mm (426) piston =

.7854 x 88mm x 88mm x 74mm =450078

Divided by 1000 = 450cc

You can use .0007854 and not have to divide it by 1000

bore x bore x stroke x .0007854 = CCs

[rubbersdown]

I tried to do the math in my head and came out that is should be 1639cc. Then switched to a calculator and low and behold ish416 is right, 416 + 4mil = 440cc.

[togup]

where does the number .7854 come from? Im math challenged!

[fauxamish]

So is an 88mm (426) piston and 4mm stroker legal to race in a 450cc class? How much of a difference would there be between using a 87mm and 88mm piston in my stroker build? Thanks