416 Kit Questions/ Good 400ex engine builders in Indiana Ohio???

[tdub400ex08]

Sorry about all the recent questions but I'm trying to build a RELIABLE quad thats faster then stock but still keeps its reliability and I keep getting mixed answers from all the honda dealers in the area and even from companies like CT, Sparks, and trinity. I would like to find someone local to speak with that could do the work reliably who has experience.

After looking into the Trinity 460 kit it seems that it may be a little more then I want to spend (to do it right) and more then I need.

My goal is to get 10hp at the wheels but I don't want to loose any torq or bottom end power. What would I get it if I did the following mods?

416 11:1 piston (JE, Wisco, or CP)?
High flow filter (twinair, sparks, uni)?
ENS air box lid
Edelbrock carb (regular or 440)?
Cam (sparks X1, hot cam 1 or 2)?
Full Exhaust (HMF, CT, Sparks)?

I will add an external oil cooler like fst kit but with an Earls oil cooler. Their suppose to be 2x as efficient as the tub and fin.

What do you think?

I wouldn't mind getting a 440 kit for the extra bottom end power but it seems like everyone in the area who has built them has had head gasket problems or says they don't last long or need to be re-ringed and honed every 100 hours or so.

Thank you so much for all your help!

[Miami_Vice454]

you get A LOT more than 10 hp at the wheels bone stock.

[Pipeless416]

Originally posted by Miami_Vice454
you get A LOT more than 10 hp at the wheels bone stock.

pretty sure he meant 10 more than stock.

[Honda#4]

You forgot about porting the head also, the setup I have is flawless and makes awesome lowend power, and doing it yourself will save alot of time and money and you'll learn something from doing it.

Basically the pistons you got listed are all good, wiseco tends to be off of there piston specs so I read but never concured this. Ditto to the air filters can't go wrong with any of them K&N tends to flow more air but sometimes dirt may pass through, the sparks and Uni I think are basically the same filter. As far as carbs are concerned the people say that the edelbrock carb is hard to tune but some people have had luck with them, im not on the 450r bandwagon but people say that you gain good throttle response and power is increased slightly. Now depending on where you want your power the cam will influence this, with the 416 i'd choose the stg 2 hotcam cuz its drop in and doesnt require hardened rockers like the webcams do. For the exhaust it all comes down to personal preference but in the end keeping it quiet is the way to go.

With the 416 you wont have to worry about overheating issues mine runs at 220-250 on a hot day. Switching to race gas made it run 7-10 degrees cooler but is not needed with a 416 but 93 is required.

[Loshe]

With the 416 kit you should not lose any reliability.As for the piston I would run the JE, the air filters you listed I would run the Twin Air, as for the carb you could rejet your stock carb and make it usable with the 416 kit, the cam i would run the hot cam unless you want to put hard faced rocker arms in to without knowing what type of riding it would be hard to say what stage to run.The same goes for the exhaust it depends on where you ride and if there any noise restrictions.




2000 400ex
AC nerfs/ front bumper
K&N filter with prefilter
Dynojet jet kit
full yoshimura exhaust

[Miami_Vice454]

pretty sure he meant 10 more than stock.

ok that sounds reasonable.

[pbblaster2]

i am in the same boat as this guy, i am looking to ride sport class at local series and i race a yfz at nationals and i am not as knolagible on the 400 this is what i want to do

426
je piston 11:1
stage 3 hot cam
ground stock header
hmf slip on
port and polish
stock carb
uni filter

sorry if you think i am jacking your thread just looking for some help also

[TRXRacer1]

Originally posted by pbblaster2
i am in the same boat as this guy, i am looking to ride sport class at local series and i race a yfz at nationals and i am not as knolagible on the 400 this is what i want to do

426
je piston 11:1
stage 3 hot cam
ground stock header
hmf slip on
port and polish
stock carb
uni filter

sorry if you think i am jacking your thread just looking for some help also All good but the P&P is pointless with a stock carb and pipe. You'll need at least a 450r carb and a full exhaust to justify it. If you can run race fuel get the 13:1.

[matt14c]

Originally posted by pbblaster2
i am in the same boat as this guy, i am looking to ride sport class at local series and i race a yfz at nationals and i am not as knolagible on the 400 this is what i want to do

426
je piston 11:1
stage 3 hot cam
ground stock header
hmf slip on
port and polish
stock carb
uni filter

sorry if you think i am jacking your thread just looking for some help also

I may be wrong but I think the stage 3 hotcam was made primarily for the 440 + bore sizes. Not sure how it would work in the 426. Yes a port and polish would be a waste of money with just a slip on and stock carb. The 450R carb is actually a large carb I believe 41mm there are a couple smaller carbs than that. FCR 39mm and Edelbrock is also a 39mm. Go with a different carb full hmf system or equivalent and stage two hotcam and that setup should rip!

[TRXRacer1]

Originally posted by matt14c
I may be wrong but I think the stage 3 hotcam was made primarily for the 440 + bore sizes. Not sure how it would work in the 426. Yes a port and polish would be a waste of money with just a slip on and stock carb. The 450R carb is actually a large carb I believe 41mm there are a couple smaller carbs than that. FCR 39mm and Edelbrock is also a 39mm. Go with a different carb full hmf system or equivalent and stage two hotcam and that setup should rip! Stage 3 works good with any high flow build. 41mm is big but it's not the most efficient carb. A 39mm FCR could actually mix and flow a little more.

[pbblaster2]

ok thanks for the imput guys, the p&P is free soo ill start looking for a carb

[MtnEX]

From what I have read, I think the head gasket problems are not an issue if the build is right, with good gaskets, HD studs, proper torque, etc...

I also have trouble accepting that a larger piston is the cause for having to re-build often. I'd say that's more to do with jetting, lubrication, and temperature control.


I would not be afraid to do one, but would not do it on "MY" jug. I would instead pull and stash... and get one of those 440 kits with cylinder... the "bolt-on" jobs... PUMP GAS COMPRESSION... and I would install it RIGHT with everything needed.

If it didn't work out, I could always do a mild bore on the original cylinder.

[ish416]

I had Terry at Cobys Cycle from Portland, IN build my EX motor a few years ago and it still runs great.

416 12.5 JE
K&N open airbox
450R carb
Hot Cam stage 1
FMF slip-on
Sparks timing key
Ported head

It runs pretty close with stock 450s.

Its a great all around motor, tons of torque. Everyone that rides it is impressed with the power that it has.

Give Terry a call 260 335 2611.

[tdub400ex08]

Thanks I'll call Terry sometime and talk with him about the build. I'm only about 30 min away from portland.

[Miami_Vice454]

ish416, what octane do you run? i was thinking of doing this same compression

[MtnEX]

Originally posted by ish416
I had Terry at Cobys Cycle from Portland, IN build my EX motor a few years ago and it still runs great.

416 12.5 JE
K&N open airbox
450R carb
Hot Cam stage 1
FMF slip-on
Sparks timing key
Ported head

It runs pretty close with stock 450s.

Its a great all around motor, tons of torque. Everyone that rides it is impressed with the power that it has.

Give Terry a call 260 335 2611.

Good post and an honest one too.
Thanks.

That is a build list I have not seen before.
Interesting choices.


Originally posted by Miami_Vice454
ish416, what octane do you run? i was thinking of doing this same compression

ish416 I was wondering the same thing.

Haven't seen anyone run a Sparks key with compression that high either.

[jasonwayne222]

from what ive read and what the website says, if u put in a sparks key with that high of comp. ur gonna go boom, but look it up for urself,

I have a question for u 416 guys, i just got done doin mine and i couldnt find a head gasket specifically for the 87mm piston, called chapparel and looked on ebay and closest thing i could find was a 86mm gasket kit, it works fine on my 87mm piston, plenty of clearance and i would think it would be better anyhow because u have more material, smaller hole u know

anyhow where can u get the 416 gasket kit?

[Honda#4]

You use a stock gasket remember its only when you get a 440 that you need a new sleeve pressed in and thus buying a bigger gasket.

[400ex28]

pick up a service manual and do it yourself...

[TRXRacer1]

Originally posted by MtnEX
From what I have read, I think the head gasket problems are not an issue if the build is right, with good gaskets, HD studs, proper torque, etc...

True and you don't even need HD studs. There's nothing wrong with the stock studs, just the material they sit in. Inserts do the exact same think the HD studs do. Do which ever one is cheaper.


Originally posted by MtnEX

ish416 I was wondering the same thing.

Haven't seen anyone run a Sparks key with compression that high either. Yeah that's pretty wicked. I'd like to know how those temps are being controlled. That plug is firing in massive compression if there is a key in there.


Originally posted by Honda#4
You use a stock gasket remember its only when you get a 440 that you need a new sleeve pressed in and thus buying a bigger gasket. By 87mm you should be using an oversized gasket. By 88mm, even with the stock sleeve, you need the BB gasket. The sleeve doesn't matter as much as the bore.

[pbblaster2]

is the 88mm bore reliable

[TRXRacer1]

Originally posted by pbblaster2
is the 88mm bore reliable Yes. Don't believe the hype that the sleeve is too thin at 88mm. It's just the last safe bore you can do.

[ish416]

I usually run AV fuel without de-icer.

The AV fuel is 100ll. Which is about 103 - 108 octane based on pump gas ratings. The low levels of lead help with detonation and keep the temps cool.

Also, I am running the 400ex gasket and not the XR gasket which is thinner.

I would say that my compression ratio is actually around 12.2 - 12.3:1.

Worst thing about av gas is that the packing in my silencer lasts about half as long as it should.