440 kit vs high comp piston stock bore

[jsmith2232]

how would a 440 kit and a hotcam compare to a stock bore,hotcam and a high comp piston?

[rooster300ex]

the 440ex would for sure have more power, then them other mods, on stock bore. heck 440 kit it and cam it up.

[jsmith2232]

Roughly about how much hp will my quad be running at if i was to put the 440 kit in it.

[ZSK]

With a properly built 440 you'll see mid 40's on the HP numbers. With the "kits" you might see 35. I'd do a stock bore hig compression piston and hotcam. That is the best bang for your buck. Unless you have $2000 to do a full 440 the way it should be, do a stock bore piston and cam.

[jsmith2232]

what would the hp gains be with a stock bore and a hotcam?

[ZSK]

Don't know, in a drag race the stock bore was only a bike length or two behind my 440 kit. After the 440 was built the stock bore couldn't touch it let alone the 440 kit.

[jsmith2232]

what is the difference in parts, labor and cost of the kit and a properly built 440 that gets you that extra?

[ZSK]

By properly built, I mean the parts that will get you reliability and a powerful engine. With the kit, you bore the cylinder and press in a new sleave. Also bore the cases for the larger sleave.

To do it right, at the minimum you need to replace the headstuds ($75-100), cam chain ($35), clutch components (Price varies, $200-$800), Rod all to heavy duty specs. To gain the most performance, you will need a cam, fcr39 or fcr41 carb depending on application ($300-400). A good full system ($300 used, $500 new), LRD or Sparks are about the best they come. An aftermarket air box and K&N or UNI filter. Add in a bigger oil tank for added cooling and possible a secondary oil cooler. Add in all of the labor of a machine shop or builder to the cost, if you can't do the work yourself, and gasket kits as you go. I built my 440 over two years replacing everything as it broke or wore out. From my experiences stay with stock displacement unless you like working on an engine that much.

[jsmith2232]

wow thats alot more than i thought it would take, i work in a machine shop on a cnc mill every day but that doesn't make up for the lack of experience of working on engines. i guess i will just go ahead with the hot cam and high comp piston and keep it simple.

[lostcreekz450]

do both 440 cam and high comp piston way better results

[cals400ex]

the 440's gain in the torque department. they have a lot of power at low rpms. a high compression stock bore piston should run fairly close in a drag race. you won't have as much torque but you will have a higher revving bike. compression is more important than the bore size typically. however, the larger bore you go, the smaller dome is needed on the piston to acheive a desired compression ratio. a smaller dome means a better flame travel across the top of the piston (more efficient). our 440 has less top end speed too. i guess that is due to the heavier piston. my 426 would outrun the 416 and the 440 both everytime. the 416 and the 440 are pretty close in a drag race until top end. this is where the 416 will pull away. on a track the low end power of the 440 is nice. it makes really good power down low. it wont' pull high rpms worth a crap compared to our other builds though.

[racin richard]

Originally posted by ZSK
With a properly built 440 you'll see mid 40's on the HP numbers. With the "kits" you might see 35. I'd do a stock bore hig compression piston and hotcam. That is the best bang for your buck. Unless you have $2000 to do a full 440 the way it should be, do a stock bore piston and cam.
2000$ i don't know who has a kit for that much but if you go to wiseco or rocky mountain you can get a kit 220 and i paid 133 to get the new sleeve bored and put in if you no how do do it yourself do a 440! you'll be happy

[jsmith2232]

i have all of the equiptment including mills, tooling, precision measurement instruments at my fingertips and i'm sure i can do it accurately enough, but it's getting things apart and putting them back together the correct way that worries me, do you know if there is any step by step instructions out there?

[wilkin250r]

It's more than just the cam chain and heavy-duty studs. There are lots of little tips and tricks involved with a properly-built engine that gives it and advantage over a do-it-yourself piece of junk.

Lapping the head and cylinder to make sure they are flat.

Properly setting the ring gap, bore clearance, squish band.

Calculations for optimal gasket thicknesses, thinner isn't always better, but too thick and you lose power.

If it was just a matter of bolting s**t together, there wouldn't be a need for race shops. There's a lot more to a reliable, high-powered motor then just the individual components.

True, a do-it-yourself 440 kit will give you a power increase over stock, but not quite as much as a professionally-built race motor.