Big bore kits

[Dex]

What is the magic number? I wanna keep reliability but I want lots of power out of my 400ex what is the best size that keeps good reliability? Also I wanna be able to get pipes and stuff for it can you do that with a big bore? I am thinking 415, 416, 425 and 440 I don't know if the 500 would be to hard to modify and get parts for and if it would cut down on reliability to much to.
Help me out.

[twisted threads]

I have had no problems with my 440 at all. I think the biggest problem is to much compresion(i think) and it starts making them unreliable.

[racer_ex55]

Adding more cc's doesn't really get rid of reliability it's once you start adding more compression because it will run hotter. Adding race fuel will help this. You will be able to get any of the same pipes that you would with any bore. It's only once you start pushing a lot of air that you would need any special exhausts. Those are only bigger headers.

I am going to get a 465 to race next years it's been proven reliable.

[oynot400]

It seems like that there are more and more good engine builders any more. So no matter what kit you choose, chances are you will have a good reliable engine.
You need to ask yourself 2 main questions before doing this type of mod.
1. What are you going to do with the quad? Race, mx, tt, oval, ect. Or are you going to mainly trail ride?
2. What can you afford? Even if you send in your engine to have a 416 installed you could run up to some serious cash. If you can do the tear down and assembly yourself that is a big cost savings.

This is what I recommend, right or wrong. If you are going to race 100% of the time. Then a 416, high compression piston, the hole 9 yards!
If you are going to trail ride then a 416 or 440 compression under 11:1. The nice thing about a 416 there is room to go to a 426 in time, then a 440 if you feel it is nessary.
That is just my thoughts. I hope this helps....:D

[oynot400]

GNCCer,
Is that 465 kit a 440 that is stroked? or is it just bored that much? :confused:

[flaneledholes]

Originally posted by oynot400
GNCCer,
Is that 465 kit a 440 that is stroked? or is it just bored that much? :confused:

It is a 440 stroked to a 465...

[JabberJaw]

I keep telling my wife that very same thing.....

"Honey!, It's a 6 inch stroked to an 8 inch....."

[racer_ex55]

you can also get a 465 from sparks that is bore only. It uses a 92mm piston. I am thinking about getting that next year but i hear that they rev slow and I race mx so....

Is that 465 kit a 440 that is stroked? or is it just bored that much?
Actually the 465 i am going to get is a 426 stroked 6mm
if you stroke a 440 6mm yuo get a 473 if y stroke a 440 4mm you get a 460 ( that is what LRD does)

[oynot400]

Any idea what it would cost to just get the crank? Since I have the rest of it done already. :devil

I am not sure on prices i think it is like 300 to have to crank stroked. you will need a diferent piston, a good rod and i belive you need to have the counterbalancer trimmed to fit. It is going to cost less than a thousand to to have the things i just listed done. Call For Dirt Only after 6pm and mike will be more than willing to give you the prices of everything.

Nathan

Sorry For Dirt Only phone# 740-967-1078

Nathan