438??

[ridinthedunes]

I was asking my local builder about a 440 kit and he said that
I should just bore the thing out to 438 so I don't have to buy
the sleeve. His thinking is that I will save money and can always
sleeve it next time. I was wondering if it would displace heat
well enough and he said that he has done 3 of them and
hasn't had a problem. What do you guys think?
R/T

[Dave400ex]

438 is way to far on a Stock Sleeve. The 425/426 is the farthest you want to go on a Stock Sleeve. If you want a 440 get a new Sleeve.

[ridinthedunes]

I was thinking the same thing but I couldn't really give
him any reasons, he said he hasn't had problems with
overheating and I'm not knowledgeable enough to put
up a good argument. Any others???

[ridinthedunes]

Gotta be some guys out there with some opinions??
good....bad.....any would be nice

[MIKE400EX]

He's probably confused. Ask him how much of an overbore "his" 438 is.

[ridinthedunes]

He didn't seem to know off the top of his head.....he said,
80......100......"something like that. Why, so the numbers not
add up?

[josh]

ya, i would just go with a 426 or 416 cuz they rev faster and my dad's friend said he wasn't overly impressed with the big bore 440, and he basically has it built to a race motor now, i say go with the 426 cuz i have heard the high comp 440 has a tendancy to blow and frie rings a lot faster than anything else:(, i would do a 426, that's what most mx people use, right.....

a 426 is .120 over I have never heard of anyone going bigger than that on a stock sleeve. when you resleeve and put a IMS 440 kit in it only bumps the disp. up to 432. Please ask him how big a bore this is like a 89mm or what (89mm is a 432) and how much over he thinks that is. If he doesn't know i don;t think I would trust him to touvh my quad.

[crashinmatt]

i think the guy is confused. 80 over is a 416 and 120 over is a 425/426. so for a bore that size, ur lookin at 160, which, in my opinion, is way too far.

[Sick0]

Ask him if he smokes crack.

[ridinthedunes]

Thanks!
Does anyone know what the formulas are to convert
bore to disp. to what mm the piston is etc.???

[Dave400ex]

No but 87mm is 416, 88mm is 425, and 89 is the 432. I think they make a 89.5 which I`m not sure what that is.

[ridinthedunes]

He said he thinks it's a p-12 wiseco lightweight. He said it's
the last bore??

[ridinthedunes]

He also told me to use a Web Cam, he thought it was the high
rev or tall grind?

[Dave400ex]

My advice is to quit listening to your Dealer and call an Engine Builder. TC, Sparks, and Duncan are good ones.

[ridinthedunes]

this is a local engine builder, did good work on my banshee and
seemed to know what he was talking about on the shee.

[ridinthedunes]

It's not looking good:eek:

[Castor-426ex]

Originally posted by Sick0
Ask him if he smokes crack.


lmfao!!:D ditto youre gonna have a transparent cylinder...

I just happen to have this info in front of me for something I am looking for the 440.

First you need to remember that the original wiseco and JE 440 was only just under 430cc (+or- depending on the deck/piston heights)

Ross pistons offers the following (www.rosspistons.com)

397 85mm (3.346) stk
406 86mm (3.386) +1mm
415 87mm (3.425) +2mm
424 88mm (3.465) +3mm
440 89mm (3.508) +4mm

They also offer the following for overbores of the 88.5mm (426?) 440's
430 88.60mm (3.488)
440 88.97mm (3.503)

If you think of the orig wiseco 440 being only 88.5mm and the 89mm and 88.97mm shown here you begin to wonder how they come up with the cc's. I guess they are allowed to guestimate or something.

What I mean is if 89.0mm =440cc then 88.97 deff has to be a little less and 88.5 a whole lot less but all are referenced as 440 so go figure.

As an answer to your question I think your builder may have something that works since the 438 he has suggested may only be a bore of 88.2mm depending on how he cme up withthe figure. What you need to know is what bore he is looking to do not what cc's he is trying to get cause that will tell you exactly what he intends to bore the sleeve to which is what really matters.

Most of the people here tend to believe what they have learned and are afraid to try out a new idea etc. Would I go that route, well prob not cause I dont understand why not just resleeve unless you seriously cant go the extra $$$.

[ridinthedunes]

Thanks for all the help. I'm gonna go talk to him this weekend
with all the info. everyone has given me.
Thanks,
R/T

[MIKE400EX]

440ex4me
Just to clear things up a little. The displacement of an engine refers to the total swept volume of all the pistons/cylinders. The piston/deck heights have nothing to do with the displacement (although very key to compression, squish etc..).

Advertising and selling (ie.. making money) is the main reason why displacements are quoted or "rounded up" to a higher number. After all if you're looking to upgrade, doesn't 440 sound better than 430 or 435?

[Burden7]

Just for reference, here is the formula for finding the displacement of an engine in CC's.

Bore * Bore * Stroke * .000786

So, an 89.5mm piston = 440.7cc and an 89mm piston = 435.8cc

I would take the advise of everybody else and only go as big as an 88mm piston in the stock sleeve.

[ridinthedunes]

That's exactly what I was wanting. Does anyone know what the
wiseco p-12 is (mm)?

397 85mm (3.346) stk
406 86mm (3.386) +1mm
415 87mm (3.425) +2mm
424 88mm (3.465) +3mm
440 89mm (3.508) +4mm

Actually a 87mm piston gives you 416.12848
and a 88mm piston gives you 425.74963 (hints why some people call it a 425 others a 425 it is in between the two0
and a 89mm is 435.48.

Not to be a arse but according to wisco use bore x bore x stroke x .0007854 for a more acurate size. so for a 438 without being stroked he would have to have a 89.257061mm piston

Wow I thought I was getting confused again, till I spoke with the guys taking four days to measure the sleeve who call me up and say that its 88.5mm. I almost lost it and was gonna just go pick it up and try the next place on the block.

Damn does any one in NJ have a clue on these things.

[ridinthedunes]

With the info that burdon7 gave in the thread, it will be a 332.....
if that's what you're asking.

[josh]

lol, too many numbers at one time

[ridinthedunes]

Does anyone know the formula to figure out what 20/40/60/80.....
over means in mm......ie. what size piston I would have on my
400 (85mm) if I went .80 over?

[crashinmatt]

i believe 40over is 1 mm, so 20over would be.5mm. im not sure if there is a formula but i think that is close. a 416 is 80 over, so that would be an 87 mm piston.

[ridinthedunes]

I'll buy that for a dollor:)