Valve train Issue, 416 build

[vinson581]

so i picked up a really really clean 03 ex for 1000$ because i was long over due on owning a 400 :macho , it had a slight ticking sound, figured it was the cam chain, tensioner, or just the valves out of adjustment. it starts right up but ticks decently bad, so i pulled it apart and it seems as if one of the lash adjusters on the "passanger" side exhaust valve, needs to sit up MUCH higher then on the other side (to be within the .005 exhaust clearance spec). i am thinking that the valve is just bent, sound right? being i already have the motor half torn down, and i have an 11:1 416 piston new in the box from my old bike i figured what the heck id throw it in there :) now for my real question what valves are you all running, this bike is going to be a trail bike so i dont need anything crazy at all, trying to keep the budget low as i just built a 2010 yfz450r for mx so funds are kinda low.

i was thinking about this setup

416 piston
CRF450r 02 cam chain
kibblewhite valves (im scared to use cheap valves)
mabey a hotcam (not sure may keep the stocker)
NOWWW the question is to get another stock tensioner, or use a manual tensioner...how are they?

i will try to get some pics of the head to show what i mean about the lash adjuster being far out.

http://i20.photobucket.com/albums/b206/vinson581/2011-03-24_11-57-40_481.jpg
http://i20.photobucket.com/albums/b206/vinson581/2011-03-24_11-57-57_69.jpg
http://i20.photobucket.com/albums/b206/vinson581/2011-03-24_11-58-44_283.jpg
http://i20.photobucket.com/albums/b206/vinson581/2011-03-24_11-58-34_849.jpg

^ those other pictures are just for reference on anyone needing to know how to set the timing on a 400ex, cam lobes, down, top dead center, t mark lined up on flywheel

[tri5ron]

11:1 is putting you into or very near pre-detonation for pump gas, and is also going to cause more heat.

Trail riding often is at a slower pace with limited airflow for cooling.

So you will be building a air cooled trailbike, that will probably need special fuel, that creates more heat, and gets less airflow.


next your saying you want to keep the cash spent to a minimum, yet you want the KW valves.
OEM valves are plenty fine for 95% of the applications and builds out there, and you are certainly not building yours into the other 5%

not trying to be a jerk here, it just dosent make sence to me.

As far as the tensioner goes, personally I'd just stay with a stock type, not a manual. remember, 400EX's just do have a noisey top end.

My opinion of the perfect trail bike build, that will never let you down is ...
Stock piston, or up to 416, at 10:1, or 10.5:1 (MAX.),
foam air filter,
muffler, (slip-on), of your choice,
ground welds on stock headpipe,
stage 1 (or 2) hotcam, or equivalent,
04-05 450r carb properly jetted to your elevation/temps
Sparks +6 ignition timing key.

upgraded front shocks of your choice,
steering stabilizer of your choice,
XR's Only Oil temp gauge (just to keep an eye on it),
Spal fan, or larger cooler if you need it,
gearing stock or 1 tooth down on the front


It will run on pump gas, be a stump pulling torque monster, never overheat (even in the slow and rough terrain), will produce about 34 hp, (over the stock 24-26 hp), still be just as reliable as a bone stock machine, and always bring you back home.

(jmho). that, and a $5 bill will get you a gallon of gas.

[CJM]

I have a 416, similar setup to Rons-but it has an 11:1 piston and stage 2 cam.

It never gets to hot for trail riding, if it does (which is SUPER rare) Ihave an electric fan I can turn on thats mounted to the oil cooler. you can also add a larger oil tank and that helps too.

Buy stock valves and replace the springs, they are decently priced and will work fine. You dont need kibblewhites.

But I would do 10:1 and a +6 key if I had to do it all over again just so I can run the key. Im contemplating using one of the custom +3keys member wheelie makes with my setup-but he does say you need 100 octane. Now whether its really needed or not IDK-I might chance it.

[vinson581]

ment 10:1 hit the wrong key on my phone when i posted this.

i dont know why everyone says 400ex's have a noisy top end, all the ones ive owned were always extreamly smooth, a yfz on the other hand now thats loud!

going with kw's because oem valves cost more money by about 10$ per valve, so it makes no sense to go oem

this didnt help at all answer my question really on the lash adjuster lol

[vinson581]

well i said i was going to save some money but i figured im going to build it once and build it correctly...

new valve guides, and seals
Kibblewhite Black Diamond Intake and Exhaust Valves
416 10:1 piston
Hotcam stage 1
Heavy Duty Timing Chain
cleanup port

other fun stuff


grind exhaust welds
put all my spare parts off my old ex on

works tripples, burgard arms, g-force axle, +stem

[matts27]

Tear it down before spending all that money on valves. A simple lap job will match or exceed all that cutting you need to match NEW valves back up, plus shimming to get the height right. I would look at the contact points to the rocker assembly and see if the service manual gives you specs on service limit size and dimensions. I don't know if the clymers has it in it but would almost guarantee the Honda book would. Also, is the adjuster running out of screw, the pic is upside down and you can't really see the other rockers. They should all be pretty close, also the head could be carboned up bad holding the valve on you on the spring might be soft causing the added adjuster height. On tear down you should see it.

A bent valve would give you a lot of indications with a rap at idle and run real bad, just my two cents, Matt

[Stark]

Originally posted by vinson581
ment 10:1 hit the wrong key on my phone when i posted this.

i dont know why everyone says 400ex's have a noisy top end, all the ones ive owned were always extreamly smooth, a yfz on the other hand now thats loud!

going with kw's because oem valves cost more money by about 10$ per valve, so it makes no sense to go oem

this didnt help at all answer my question really on the lash adjuster lol

might be just a bent rocker arm.

[vinson581]

it does not idle well at all, it will sputter every other fire of the crank which would kinda make sence being that when it hits the exhaust stroke it sputters, and runs poorly. i ddint think these rocker arms could bend? arent they cast? always thought they could crack or break but not bend.

[Stark]

It was just a guess.. I adjusted my valves on a old Suzuki SP600 I had when I was younger. Single cyl, 4 valve. After I got done, i noticed one valve was adjusted higher than the other. Took the cover off and noticed that the rocker arm was bent on one.

Just take em off and look at em.. i'm sure you'll find the culprit! :)

[vinson581]

thanks man i appriciate it! im going to pull the head off right after i type this and pull the valves out, either way i have an entire new valvetrain that will be here tomorrow :) i am slightly worried about that rocker tho, i shall soon find out

[Stark]

Shweet! :)

[vinson581]

well all the lifters are perfect, but im still a bit confused how one of the lash adjusters is SO far up, i am starting to think that the decompression mech on the cam is causing this? is this possible, where it is hitting the lifter and causing it to stay "stuck down" thus me needing to screw the lash adjuster way far out?

here is the correct one adjusted at .005 TDC comp stroke

http://i20.photobucket.com/albums/b206/vinson581/2011-03-24_18-59-13_909.jpg

and the incorrect looking adjuster also adjusted at .005 TDC comp stroke

http://i20.photobucket.com/albums/b206/vinson581/2011-03-24_18-59-26_196.jpg

im not thinking it cant be a bent valve because if a valve WAS bent the valve would actually sit lower, or stick open, theres no way it would sit HIGHER! im betting my money on that decompression assembly on the cam.

[CJM]

When your adjusting them, are they loose?

I had a similar issue and for whatever reason that time I adjusted them I had a hell of a time getting to to TDC properly.

[matts27]

Mic the cam lobes. The so called "good" rocker might be the culprit. Meaning the cam could be worn requiring such a long adjuster. Might be that simple, I don't think the adjuster can fail in a way to hold the valve open. Let us know what you find. Matt

[vinson581]

when im adjusting them they are "loose" as in .005 of clearance, im postitive im at tdc because both the exhaust and intake rockers have play...and im not to sure how the lifter could be bent down? it could really only get "bent" up by means of a valve hitting the piston which is has not done.

do you guys understand what im saying about the compression relese mech on the cam causing the exhaust valve to "stick", im thinking about just removing the comp release dowel and spring...same as if i put a cam in...shouldnt be a problem in my mind right?

and matt its not requiring a "long adjuster" its requiring the adjuster be turned very very short "counterclockwise"

and im referenceing the 3 correct looking adjusters to my old "new in 2002" 400ex pics when i did the valve adjustment back in the day. and the 3 look the same so im positive, 3 out of 4 are correct. and the one thats incorrect is on the decompression side.

[vinson581]

and this is what i mean here is a basically new 400ex i had...look how the exhaust adjuster is very much the same distance as the "correct" one on the bike im working on

http://i20.photobucket.com/albums/b206/vinson581/p7300053.jpg

[CJM]

Ok after all the info and pics I vote either:
-rocker arm is bent somehow
-valve is bent
-cam is messed up
-out of time perhaps by the cam gear.

Not really sure which one it is, you could try new valves and see what happens. I would pull it all apart and carefully inspect the valves, rockers, etc and look for defects.

Sorry not much more advice than that :(

[vinson581]

-rocker arm is bent somehow- took rockers out of head, they are fine i measured all of them
-valve is bent- possibly but ive never seen a valve stick UP further then it would go normally,
-cam is messed up- possible, but the cam "looks" fine
-out of time perhaps by the cam gear- if out of time both exhaust valves "should" be sitting incorrectly being they open as a pair...

im going to go and say its the cam decompression device, im going to pull the pin out and i am betting it going to be the culprit...reason i say so is its a very uncommon problem, i usually have the uncommon ones lol, but in all seriousness, by reading what i have it seems like a bad decomp mech could cause only ONE exhaust valves to stick!

[vinson581]

as i thought!, the compression release was stuck causing the valve to stick, got it unstuck, and walahhhh it runs so smooth sounds just like my new 400ex did back in the day :) guess i shall be returning those parts...good thing there is no re-stock fee!

[Stark]

awesome! glad you got it fixed!