Getting the 400ex to keep up with 450's and spank the kfx/ltz

[400exrapes]

I got one friend with completley stock yfz450 and 450r, and one friend might be getting a kfx400 completley stock. I dont want to just beat the kfx400 but spank it and coming close to the 450's is all i want not beat them but be close. What do I need to do that will keep the great reliabilty of my quad to do all this. And dont tell me just buy a 450 dude.

[Ruby Soho]

426, or 440

[400exrapes]

yeah but i hear that kills the reliability i picked honda for the speed and reliabilty and i dont want to like destroy it

[Ruby Soho]

if 440's are built properly they will last. same with 426's

i think a 416 would beat a kfx also

[Wheelie]

Check out www.powroll.com. Take a look at the 440 stroker. Combined with a good cam and porting, you'll have no problem keeping up with the new 450's. Go with the HD rod, and the machine will be very reliable as well.

[zrpilot]

I think a 416 will keep up to a stock 450R, if built right!

[idro]

If you're a good rider you have nothing to fear, 400's arent meant to be top end queens. I can keep up with my buddy and his 450r all day long on trails...


Your honda will take water, take a beating, and take anything you will put it up against.

[ryandu]

You will eat them up with this setup and have a very reliable setup.



You will not have to run race fuel, you will just have to jet your bike accordingly.

11:1 piston, stock bore (High rev can be good)
stage 1 or 2 camshaft
make air flow from K&N intake, through a good flow exhausst like HMF.
leave off jug gasket, and get a thin head gasket
port and polish your head, very easy to do. While in there, cut the bottom of the valve guides off to make a clean flow.
Add heavy duty valve springs, and clutch plates

Last but sure not least, will give you around 6hp.
TRX 450R Carb, get it from service honda for $170.


later

[Brehmmotorsport]

yeah i don't think you are going to get a 450 on top end without a big bore kit. However. I race harescrambles and need the reliability too. Get a ehs or some sort of open air box and a k&n. Sparks timing key advance. And by a good fuel. C12 or what I run U4. Bump up that pilot jet and some may argue but get a rev box. ( the timing key and rev box do opposite things). This is my setup I am running a 42 pilot and a 170 main in the stock carb mixing gas and u4 50/50. I run with the 450s and pull them in the woods. Make sure you drop a tooth on the counter sprocket too. I consistantly get awesome starts and put a hurtin on them but with all this said after you tape out in fifth gear they probably have another gear to go easy. But realisticly how often do you run fifth gear.

[Brehmmotorsport]

yeah everything I said to do you wont have to open the motor just the side case for the timing. Keep the stock cam for the quick rev. The more you try to make your stock motor pull the more the 450 has an advantage. Get a good exhaust. An open one no discs. Sparks hmf or tc.

[400exrapes]

i always here about this tc exhaust but i havent seen a good picture of a 400ex with it all i here is that it produces the most power but there website doesnt have it either

[Brehmmotorsport]

ill try to get a pic on here in the next day or so but to be honest. I love my tc and it made a huge difference but it is also insanely loud. I race and trust me as soon as that decible meter comes to my tracks I am going to be shut down. For the price I would recommend the hmf and you can get the quiet core for the price.

[400exrapes]

yeahh im not so sure cause i want good performance and goos ound the hmfs i heard are loud even with the quiet core... what about the rs3 comp series yoshi s/o i know they produce real good power i just need to know how loud it is compared to stock because our friends got a 300ex with a dg pipe and no lieits the excact same thing as the hmf with a d.g. lettering instead of hmf on it and its so loud something not that loud