440 kit where to start???

I have decided I want the 440 kit. I do about 60% drag racing on sand bars and 40% trail riding. I already have a pipe and silencer (WB R-4). My question is where do I start for the 440 kit? I know I want a cam, vavle springs, and maybe a new carb, I would like to stick with the stock carb. I tried looking for websites but had no luck. Where do I start???

[Ononewheel]

Check this site out. www.geocities.com/gtthunder.geo/400ex.html
Seems to have alot of good information with alot of different combo's. I notice a 400 with a carb and some other stuff makes almost as much power as a 440 with the stock carb. Take a look, see what you think.

[Matt Fisher]

GT Thunders website is a great place to start.

Speed costs money- how fast do you want to go?

I want to go fast but reliablity is more important to me then speed. I am looking to go about 80-85mph tops. I don't even know if this is resonable is it? I want to keep the motor reliable and dependable. Maybe just an aftermarket cam is the way to go? What can I expect from a cam compared to the bore kit? Maybe the big bore kit is not the answer at all, can other smaller aftermarket parts lead up to the performance similar to the bore kit? Also does maitance increase with the big bore kit? Thanks

[Blysster]

If it's speed you are looking for then I would got with the 416 over the 440, I beleive it's a bit more reliable too, correct me if I'm wrong. Changing you sprockets will make the biggest difference for the cost. I would also put in a jet kit and defenetly a cam. A 440 or a 416 kit without the cam and the other small mods (filter, jetting, pipe, etc) will ot make all that much of an improvement over stock.

If you are on a budget go for the XR or WB cam as you will not need to change the rockers. The 416 is much cheaper than the 440 too.

I thought about the samller bore kits as well. The only problem I have with them is that I am afraid that if I go smaller and get the 416 kit then I will just wish that I had gone with the bigger one later. So I thought that the 440 kit will slove all my power and speed problems. I have the White Brothers R4 pipe and silencer w/ K&N. I am thinking maybe a WhiteBrothers cam and a new carb. The dyno charts tell me that the 440 kit is just to hard to say no to. I haven't looked at the 425 kit either. Thanks for your help.

[400exJOE]

If you're looking for a carb, I have a 38mm lectron flatside that is set up for a 440. I would be willing to sell it for $200 and its in awsome conditions. Just thought I'd let ya know. JOE

[Matt Fisher]

A 440 is not inherintly more or less reliable than a 416. Maybe because it makes more power it stresses the motor a smidge more, but that's about it. Really not something that's worth worrying about.

The biggest detrament to making power in a 400EX is the cam, imo. The XR cam is just fine in smaller displacement, lower compression motors. It also works well for people that really value torque over top-end. The bigger the motor and higher the compression, the less effective it is.

The cheapest route to making a few more ponies would be no base gasket, a thin head gasket, and an XR cam.

A smaller sprocket will not actually increase power, but will trade top-end for off-the line power and acceleration. If you want to do 80-85 mph, I'd guess that it wouldn't be an option.

The difference in cost between a 416 and a 440 is the sleeve and more expensive boring. About a $150 difference, not alot of money. While a XR cam will work well in a 416, I really believe it's too small for a 440. You'll be leaving a bunch of power on the table.

For a serious increase in power, try a 440 motor with an actual compression ratio of about 10.5 to 11:1 (unless you want to run race fuel). Use a GT Thunder or WB Track cam.

The lift/duration specs for the GTT and WB Track cam are the same- although ramp angles, overlap, etc. might not be.

Imo, a carb on a built motor certainly may be worthwhile, the more built up the more improvement you'll get. Really not worth it on a lightly modded moter.

Things like filter, jetting, etc. will be needed in any combo.

If it were me, and it is actually, because I am putting the 416 kit in by bike next week, i would go with the smaller kit. The real difference is your bottom end. You will get a better take off and bottom end by going with the 416, then the 440. Yuor motor will be stronger throughout, except for the top end. How do i know.. research. I have looked at several bikes with the 416, 440 and races them all. My stock bike will run with the 440's for the first 50 yards or so, then the power of the 440's pull away. But on the 416, he has me from the start. You have to think, how often do i race in 5th gear wide out. If it is frequently, then maybe the 440 is for you, but I will tell you what, by the time i get to 5th, the race is over. So there you go, wiseco makes a 416 w/ 11:1 compression and JE has one 12.5:1 An excellent site to check out is www.sparksracing.com they can hook you up. Anyway, thats my opinion.

Duneflyer
1999 400ex
DG nerfs
PRM six pack rack
ITP holeshot rears
K&N filter w/ pro flo kit
38 mm lectron carb
pro race series webcam
Works performance front shocks
Big Gun race series full exhaust
::coming soon:: GNCC Curtis Sparks 416 kit from Wiseco

[JustRace]

I believe that info is backwards... Last I knew the 416/440 had similar top ends but the 440 is more low end.

I'm sure that you will be happy with what ever you choose.

Keep in mind that a 416 probably won't need the heads ported for increae flow, while the 440 will have to. I was at Dumont this weekend and a 416 with a WB mid cam was beating the 440's with the same cam. Reason It couldn't breath and was losing lots of races.

My mostly stock, jetted, slip on WB, and dyno tuned. with 235Lbs rider was losing by about 5 bike lengths to the 416 and 2 to the 440's.