bore help!

[lillbro11]

I'm trying to figure out 400ex bore info.

If I have a 400ex and bore it from the stock 85mm to 86mm.
is that considered a 416 bore?

and if i have it bored to 87mm.
is that considered 426 bore?

[honda400ex2003]

400=85mm
406=86mm
416=87mm
426=88mm last on the stock sleeve

440=89mm and needs a new sleeve to run

hope this helps you out when buying a piston. steve

[underpowered]

^^^what he said.

but i would suggest a new sleeve for anyone going to a 426 bore as well.

my 426 on stock sleeve had a tendency to run quite warm.

[lillbro11]

Standard bore- 397cc or 85mm

402cc- .040 over or 86mm

406cc- .060 ever or 86.5mm

416cc- .080 over or 87mm

426cc- .120 over or 88mm

440cc- .160 over or 89mm

also...

440cc with an extra 4mm stroke = 460cc

416cc with an extra 4mm stroke = 440cc

I found everything thats for the help.

[honda400ex2003]

85.5 is a 402 and 86 is 406 with the .5s being rings only just about all the time. they are just for a slight cleanup and re ring option. I also second the notion of running a sleeve with the 426 if you can find one. steve

[honda400ex2003]

all of these are with the +4mm stroker
420 with 85mm
430 with 86mm
440 with 87mm
450 with 88mm
460 with 89 mm
according to powroll for some of them
these round off the 6s with the 4 mm stroke extra. these are all rounded a bit from when they are converted to L them multiplied by 100 to get the numbers. 3 decimal places are needed to see how they round each way to make the actual call. the L finder i used only gave 2 decimals.

steve

[lillbro11]

i'm doing the math and 416 with 4 mil stroke is 426.
dont kill me if i'm wrong lol

[lillbro11]

86mm= 406
87mm= 416
88mm= 426
89mm= 436

with 4 millimeter stroke

86mm= 430
87mm= 440
88mm= 450
89mm= 460

sorry i was using my phone. these should be right but check and make sure.

[honda400ex2003]

you are correct now. lol. for future when people look at it to find how we did this. 85mm bore stock, 70mm stroke stock, 74mm stroker

i used this
http://www.race-cars.net/calculators/displacement_calculator.html

then multiply the L by 100 to find the cc's for the machine. Oh and WELCOME to the site. steve

[Ryan'07400ex]

Lots of good info in this thread, it should be stickied or put in the popular thread "folder".