A faster Honda

[gofaster]

I need to gofaster!
Question:
I want the acceleration of the 450, but can I get the same acceleration with a modified 400 and still get reliability?

Seems like a bored out 400 with hot cam, 13:1 piston, larger jets and big pipe will provide the power, but it also seems like it would overheat and not last long.
Is this why Honda adds watercooling to the faster 450?

I do not race professionally, but I like to hit the local Missouri ATV parks racing friends and ride for hours when its 95°F. I want reliability. Am I better off getting a stock watercooled 450? Anyone have 5-10 years of reliable performance from a heavily modified 400?

Comments appreciated!

[A A R O N]

First of all, I wouldn't put 5-10 years on a STOCK 400ex.

That's a LOOOOOONG time to run ANY sport quad without a few engine rebuilds.

A 400ex motor with a larger piston, cam and exhaust will be plenty reliable but a once a year rebuild is always a good idea. Don't let that scare you though....once you buy the cam and exhaust, those are there to stay. Really, a new piston and rings every year will probably be fine on a 400ex. They're not that expensive either. You could do it once a year with a piston/rings/gaskets for probably around $175. Just be sure to watch the valves as well and make sure they're always in spec and when you rebuild the engine check the valvetrain and cam chain as well. I would not go with a high compression piston though....In my opinion, for the recreational rider they do not provide enough benefit for the amount of reliability you sacrifice with one. Just stick with stock compression or 11:1 even. I have an 11:1 416 in mine with a hotcam and a sparks exhaust and it does the job fine.

With a stock 450 you will also need to do frequent rebuilts, but valve adjustments, oil changes, etc will all need to be done more often because the 450 is a higher performance motor. A piped 450 is comparable to a 400ex with a piston, cam and pipe.

I will say one thing....the 400ex have proven to be a very reliable engine when treated right. As long as your mods to the 400ex motor aren't too extreme I would say that in my opinion it would be more reliable than a slightly modded 450 motor.

In your case I would go with the 400ex since you're not going to be racing it....also remember, that power is useless without a way to put it to the ground. Chassis and Suspension parts will aid this and they are far cheaper for a 400ex than any 450.

Overall, unless you're going to be racing organized races, the 400ex is probably a better choice....and certainly easier on the wallet.

[gofaster]

Thanks Aaron,
I appreciate your fast response.

I do not ride often, maybe 70 hrs/ year, but I will ride all day in the hot Missouri sun when I do. I have a 1986 Honda 200SX that has never been modified or rebuilt and still runs like new. Its hard for me to believe that a stock 400ex would not last 5 years without a new piston & rings. Are you sure that your mods are not causing overheating or a shorter engine life?

But if it is cheap and easy to add a new piston and rings, then I guess it is well worth it for the extra enjoyment of burning your buddies on the racetrack:D

For your typical rebuild, do you often have to bore and hone the cylinder, grind valve seats, replace valve guides, cam or crankshaft bearings? Is it usually just the piston rings that wear first?

Sorry for so many questions:confused:

[Old Head]

Running only 70hrs a year a 400 motor should last at least 3 to 4 years without a rebuild with the proper maintanace.

[CHEVYZ]

5-10 years on the EX is very achievable. I had 7 on mine when I went all out with it, and it still ran like it had back when I bought it in '99.

As for a 400EX keeping up with a 450 and keeping reliabilty, it depends on how far you want to go. The only real problems that most high performance EXs have are things like head gaskets...relatively cheap and easy fixes. However, you will never see the same kind of power coming from the EX. You can build them to outrun stock and slightly modded 450s with ease, but after that things really start getting hard, whereas the 450s are just starting to be opened up.

[250exkid]

for chevys...... in your sig it says 1999 440ex 2005, 06, 07 450r! do you really have them all!???????:eek2: :eek2: :eek2: :ermm:

[northwest Texas]

For the most part I agree with Aaron. I can't see upgrading to a 450 just because. Given thehours you use it a year I can see a rebuild happening no more than every 2 years.

I just did a rebuild on mine and I'm very pleased. It's much faster and I don't think I'll sacrifice reliability to be noticable.

If you're not in organized racing, the 400EX should be enough to keep you satisfied and you won't really lose any depreciation.

No doubt when it's 95 out you're going to lose power with an air cooled engine. Is it going to be noticable? If you're not seeing it now, you probably won't later.

I looked into a 450R to upgrade. I finally decided to spend the money instead on my engine (which it needed anyway) Proper maintenance will be just as high or higher with the 450 and that was one of the main reasons I didn't (other than just spending the money) upgrade. Now I'm not so sure it would've been an upgrade after riding what feels like new engine.

[81 clark racing]

get a 400ex more realiable when built right also my buddie has a 02 400ex he beats the living $hit out of and its still good to go also my other buddie i ride with has a 99 and has never opened his motor. if you take care of it and do the right maintence you will be fine.

[CHEVYZ]

Originally posted by 250exkid
for chevys...... in your sig it says 1999 440ex 2005, 06, 07 450r! do you really have them all!???????:eek2: :eek2: :eek2: :ermm: Yurp. Makes picking your bikes for trips kind of hard, but otherwise.......:p

[250exkid]

dang thats alot of money's worth of quades!!!!!
:blah:

[brokenmike]

my 400ex has been togeather for 4 years with out any trouble,and it still keeps up with the 450's. It has 440 kit,11:1 JE piston,stage 2 hot cam,intake spacer,ported,hot rod,FMF exhaust,8oz lightened flywheel,dyna FS ignition.

[stroker~riding]

Did the intake spacer help any i need more mods i got a 465 stroker?????

[400exrider707]

Originally posted by A A R O N
First of all, I wouldn't put 5-10 years on a STOCK 400ex.

That's a LOOOOOONG time to run ANY sport quad without a few engine rebuilds.

A 400ex motor with a larger piston, cam and exhaust will be plenty reliable but a once a year rebuild is always a good idea. Don't let that scare you though....once you buy the cam and exhaust, those are there to stay. Really, a new piston and rings every year will probably be fine on a 400ex. They're not that expensive either. You could do it once a year with a piston/rings/gaskets for probably around $175. Just be sure to watch the valves as well and make sure they're always in spec and when you rebuild the engine check the valvetrain and cam chain as well. I would not go with a high compression piston though....In my opinion, for the recreational rider they do not provide enough benefit for the amount of reliability you sacrifice with one. Just stick with stock compression or 11:1 even. I have an 11:1 416 in mine with a hotcam and a sparks exhaust and it does the job fine.

With a stock 450 you will also need to do frequent rebuilts, but valve adjustments, oil changes, etc will all need to be done more often because the 450 is a higher performance motor. A piped 450 is comparable to a 400ex with a piston, cam and pipe.

I will say one thing....the 400ex have proven to be a very reliable engine when treated right. As long as your mods to the 400ex motor aren't too extreme I would say that in my opinion it would be more reliable than a slightly modded 450 motor.

In your case I would go with the 400ex since you're not going to be racing it....also remember, that power is useless without a way to put it to the ground. Chassis and Suspension parts will aid this and they are far cheaper for a 400ex than any 450.

Overall, unless you're going to be racing organized races, the 400ex is probably a better choice....and certainly easier on the wallet.


Technically you should have to adjust the vavles on the 400ex more often because of the tappet system where as the shim and bucket system on the 450R although more complex to adjust, should stay in spec longer. Other than that I agree, but to me it seems like I do the same amount of maintenance on my 450 as I did on my 400. I probably change the oil more often but thats about it.:ermm:

Originally posted by brokenmike
my 400ex has been togeather for 4 years with out any trouble,and it still keeps up with the 450's. It has 440 kit,11:1 JE piston,stage 2 hot cam,intake spacer,ported,hot rod,FMF exhaust,8oz lightened flywheel,dyna FS ignition.

Small wonder your 440EX keeps up with a 450R.

:p

[DF400ex]

I also have a '99 400ex, and it's still running strong. It's never had any motor work done to it, but it's about time to. It burns a little oil on start up when I rapp on the throttle, although I cannot see any smoke when ridding, the exhaust has a little carbon on it (more than normal) so it's time for new rings and piston. I'll probably go with the 416 or 440 stroker.

Which is more reliable, 416 or the 440 stroker (416 with 4mm more travel). or 440 with stock travel?

[gofaster]

Originally posted by brokenmike
my 400ex has been togeather for 4 years with out any trouble,and it still keeps up with the 450's. It has 440 kit,11:1 JE piston,stage 2 hot cam,intake spacer,ported,hot rod,FMF exhaust,8oz lightened flywheel,dyna FS ignition.

I appreciate your reply. It sounds like you did a professional job on the engine mods. I am sure that it does keep up with the 450's. Can it run with them all day in the summer heat, 95°F, without overheating? I just keep asking myself, Why did Honda add the cost and weight of liquid cooling to the 450, unless it was required to maintain reliability and keep warrenty claims in check?

[brokenmike]

I made the intake spacer out of 1/4" aluminum,I did not notice a big difference but there was a difference. I have a oil temp dipstick and the only time I ever had it get really hot was when i was at a track and it was really muddy and my cooling fins and oil cooler got mud all in them,and I was beating on it.Once I cleaned them out it was fine.I dont know about 95 degree in the summer heat

[stroker~riding]

Thanks man i got plenty of time so i will give it a try!!!

Originally posted by brokenmike
I have a oil temp dipstick

Is that how people are guaging engine termperature?

Who makes your temp dipstick? I may need to get one. Thanx.

:)

[brokenmike]

Useing the oil temp. is the only accurate way to check the temp. Keep in mind that the oil temp. that is on the gauge is cooler because the oil has gone through the oil cooler. I got my dipstick from www.warpdriveperformance.com/ a couple of years ago and I have had no problems with it. it is like 39.95 + shipping