Hello, my fiance just got me my WhiteBrothers cam and my K&N filter and a $400.00 gift certificate to the Honda shop out where I live at for Christmas, the gift ceritficate was to pay for the extras I need to complete the cam kit on my 03 400ex. I was just curious on what you guys thought. They told her that I needed a higher compression piston and I was sure if I should go with the JE or Wiseco and which ratio should I go with. The JE is a few more bucks than the Wiseco does that mean anything. It is a stock bore and stroke 400ex it has a WhiteBrothers Revbox and a WhiteBrothers R4 muffler. Oh and by the way should I get new valves and springs and if so what kind. I want the 400 to scream up the dunes being the only kind of riding I do is in the sand. Any advice would be much appreciated. Do you guys know of any additives, you can put in the oil of the 400 to make it run cooler I know RedLine makes that water wetter stuff, but no water in the Honda. When I went to NAPA Auto parts for stuff for my new motor in my Suburburban (TOY HAULER) I ran accross this additive made by CRC one is called TOWKOOL and I'am not sure what the other is called but anyways. One goes in the tranny and one goes in the oil basically I'am rambiling along but is there anything out there like that or can one of those products in moderation be used in the oil of my 400ex. Well any advice will be helpful thanks in advance.

 

JE pistons are said to have more accurate compression ratings than the wiseco pistons and as fr the oil; i havent heard of anyone adding aything to the oil to make it cooler, most 400ex owners just add air scoops or a larger oil cooler

 

get the je piston. also, the oil in the engine is the same oil as in the tranny. i recommend not adding any additives. you can get a larger oil cooler, tank, and some air scoops

 

Ya I'am in the market for the are scoops and I'am probably gonna send my headpipe in too LRD and have it coated for $80.00 it's supposed to drop temp by 50% or more

 

The reason for the higher comp piston is to make up for the lost bottom end from the new cam. I would recomend Ross or JE but remember that since your not looking to increase the bore over what you have to for the new piston etc you may be better off looking at the stage1 hot cam and saving some $$$ that you can put towards something else.

The route that I would suggest you look into is going up to the 416 or larger and getting any of the stage2 or track/race cam profiles with a comp ratio of 11:1 or higher (depending on your prefered choice of octane) but the higher will require race fuel.

A lot of this and some other decisions depend on how you use the quad also, and what works for drag racing wouldnt be best for XC racing.

Have fun

 

Hey 440ex you have good advice. I have gone out and talked with my local wheeler shop and we have discussed the JE 416 kit and it sounds like a good idea. The thing is I have the all around use cam which is what i want I ride in the sand and hill climb and do some drag racing. but I want my power in the bottom end. I was thinking of sending the cam back to WhiteBrothers and getting the White Brothers complete 416 kit. Some people I know seem to think I should run my quad the way it is until the motor gets tired. they say I'll be throwing my money away on on the kit and to ride it with the boltons I already have see the quad is damn near new. I 'am in a situation here see I put the cam and piston on the stock motor and I run the risk of the valves and springs going bad in 50hrs or so. I could purchase new valves and springs though they are spendy will the motor be reliable and fast just doing that with the cam and all my other goodies. Then if I go with the 416 kit people say that I could run into problems with reliability and the motor going bad fast. It's a rough decision to make the people giving me the advice are guy with a extreme amount of experience with Hondas and they done all the trick stuff and this and that. They say a stock 400ex will run forever and I know this but I want to have a fast reliable beast. Ya know what I mean. Will the stock bore with all my goodies a cam and piston and valves and springs be faster then a 416 kit just wondering. Thanks in advance.

 

I have always heard to go with 11:1 compression....

 

Ok I am seeing where this can be getting confusing so I am going to try to clear up some things.

The stock 397cc engine set up makes a certain amount of power within a certain power curve etc. by modding the intake and exhaust silencer you will see an excelent gain in power (this actually is true for most atv engines) due to the greater amount of flow thru the engine, and this is why you need to rejet etc to take advantage of the additional air entering and exiting the engine.

Now go and bore that same engine 5% larger to 416cc and you will find little gain unless you up the compression or make other changes. Just increasing the bore a small percentage will only show similar increases etc. You can also go with higher compression, larger profile cam, fcr carb and porting to up the power more but at this stage its still an option to get more power or better performance beyond the benefits of the larger bore and intake and exhaust mods.

But go 11% larger in the bore to 440cc and you find you have a whole different deal. To be honest a large part of the issues with previous 440 set ups was allmost completely due to the piston or the way the piston mfg designed them and how they fit into the quad engine. The ex engine was borrowed from the XR and most of the piston mfg's were setting up the piston (specifically the piston to deck heights) for the XR and not the EX and this caused a large loss of compression. Anyhow assumeing you will not be installing a 11.2:1 piston that only creates a true 9:1 when installed and dont have the comp problems you still have to be prepared to make other mods to allow the engine to be able to flow properly with the added cc's of the new bore.

Unlike the 416 the 440 will need many of the things that were only optional on the 416. Though most "national" level motors of either size would have it all plus some not mentioned the 440 will get a larger benefit from things like the FCR carb, bigger cam, etc etc etc since it has more cc's to take advantage of the other mods that increase flow.

Sure you can compromise or cut corners and I sure did but a lot depends on how you intend to use the quad. If I was looking to race TT or just drag race I couldnt get away with the stk carb or head pipe, but since I was looking for more bottom end grunt for the woods I was able to just mod the stock items and still get a large power increase. I know the carb would still be a benefit for me due to the port work but till I decide to pump another $400.00 into this machine I will make do with whats there.

Heavier valve springs, larger valves and some other stuff is part of a list at some builders but left off at others depending on the "whole package" and there are some that will allmost never use larger valves except on the most extreme engines.

As far as your application I wouldnt bother with a kit and since you will have the intake and exhaust mods you would only need a new piston and to have it bored out etc. then if you want you can look at the other things that you could do also or later. The all around cam isnt a bad cam but do some reasearch on what others are using and their set ups plus check how they use the quads and make a decision. Its not hard to swap out a cam and it will take you longer to make up your mind or get it shipped to you than replace one.

Hope that helped clear things up [img]i/expressions/face-icon-small-smile.gif[/img]

 

Hey whats going on 440ex026 I think I'am going to keep my stock bore I've done some research while iI was waiting for you to reply all the parts I have are matched from WhiteBrothers. What I mean is they are all WhiteBrothers parts besides the K&N filter and Motoforce intake system. I've talked with some guys who have been riding for years and they tell me that a stock bored honda motor will run forever and I shouldn't have to tinker with it I should just improve whats already there. Now my question for you is. How much power do you think I'll have with this setup. WhiteBrothers R4 muffler, WhiteBrothers stage1 cam (AA), WhiteBrothers RevBox, K&N filter, Motoforce intake, JE 10:8:1 piston, aftermarket valves and springs, I already have most of the setup all the boltons and cam. I don't have a piston and the rest of the internals what valves and springs do you recommend. How many ponies do you think I'll be pushing. One more question do you think after all of this I'll be as fast or faster than a 416 or 440. Just kinda curious. Thanks

 

I know you go by sandrider but before I answer your power question lets hear about how you use the quad and what lever rider you are etc. It does make a difference to me if I want to honestly answer your questions.

To understand the "why" I want to know this think of how much different a stock banshee, warrior and 400ex are in how the power comes on in the power band etc. If you are riding mostly sand dunes you want a different set up than if your riding XC or MX etc. and the higher reving powerband of the shee would benefit the dunes or desert racer, and rock crawling or normal trail riding would be great for the low geared and mostly bottom end power of the warrior, and finally the more rounded power band of the 400ex would be great for the XC or mx type stuff.

Theres a lot more to building an engine than just installing parts if you want excelent results.

One thing I understand that I wish more engine guys would pay attention to is that not everyone ride like or has the same needs I do. Personally I prefer an engine with lots of torque and will sacrifice a little top end to get more bottom end etc, but I ride with people who are only concerned with the mid to top end power. Its all good but I believe if you dont have the final desired result in mind when setting things up you may short change yourself with an engine that isnt as strong as you would like, well at least not in the area you wanted.