400EX Step by step motor build

[rubbersdown]

Ok yall, heres the motor build I was talking about last week. My first writeup I have ever done so take it easy on me lol. Hope this helps someone.

[rubbersdown]

Here we go I started the build idea once I installed the crank. So thats where I have to start...
Install New crank bearings and crank/balancer making sure to align timing mars on crank gear and balancer.
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3365.jpg

Once the crank and balancer are installed you can start installing your transmission parts. First things first put the countershaft and mainshaft gear sets together while holding them in your hand and insert them into the case at the same time. making sure that your thrust washers are on the top and bottom side of the mainshaft and on the bottom side of the countershaft.
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3366.jpg

After you get them in place put your shift forks in their correct place, they are marker which is center C right R and left L. It is easiest to get them in place BUT leave the locator shaft out of the holes untill the drum and linkage is in.
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3369.jpg

[rubbersdown]

You can now put your shift linkage and drum in place making sure that the return spring pin is screwed into your case and the steel legs on the linkage go around it (one on each side) You can now also put the nipples from the shift forks into the drum. I usually put them in the most counterclockwise position on the drum as this is first gear. once their in the drum go ahead and put the shaft into them securing them in place
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3372.jpg

That is all that is in the bottom end of a big bad 4 stroke, not much to it, now its time to put the cases together...
I personally put a THIN coat of ultra copper on the aluminum surface of the cases because I dont trust a paper gasket and I do not want to take the chance of having a leak when it all together. I have never had a leak when using this stuff in combo with a standard paper gasket.
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3373.jpg

When putting the cases together make sure the 2 dowel pins go in and dont rip the gasket instead.
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3374.jpg

Once you have the cases set together they usually go together really easy but if they dont set by themselves just give it a little tap with a rubber mallet or dead blow hammer. You can now put in the case bolts. I believe there is like 13 (not 100% sure on the number) on the left and there is 2 on the right side. Tighten the bolts in 2 or 3 steps and in a criss cross pattern
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3376.jpg

[rubbersdown]

Next install the oil pump using a new steel gasket underneath and a new 3 hole rubber o-ring gasket on top.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3380.jpg

Now install the Timing chain sprocket, after you install the timing chain sprocket PUT YOUR TIMING CHAIN ON! (i forgot in the pic lol) once that sprocket and timing chain is on then put the main sprocket on and then the oil pump drive sprocket. All 3 of these will only go on one way with the flat tooth of the sprocket on the wide tooth of the crank shaft. Then you can put the oil pump driven sprocket on and put the washer and bolt on and bolt it all together. It may be easier to wait for the clutch and flywheel and cylinder to be on to tighten it all the way so it will have some resistance.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3382.jpg

After that you should put the shifter star and linkage on. First put the spring over the boss like so...
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3383.jpg

With the spring on you can now put on the stopper arm and hold it back (it takes some force now that the springs on) and put the shift star on being sure to put the dowel pin into the star/top of the shift drum.
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3384.jpg

After that go ahead and install your timing chain guide

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3385.jpg

[rubbersdown]

With the shift star and stopper on you can now put the clutch on. First make sure you put the outer guide onto the shaft...
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3386.jpg

Then install the outer basket and thrust washer...

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3388.jpg

then put the inner basket inside of the outer basket...

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3389.jpg

You can now install your plates. It starts with a fiber then alternates fiber steel fiber steel...the last plate will be a fiber and it goes in the shallower slots of the outer basket like this...

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3390.jpg

[rubbersdown]

After your plates are in Put the thrust washer on the shaft and then the lock washer with the OUTSIDE make facing well...outside.... and then put your nut on and tighten it and use a punch to lock it in place in the little hollow spot of the shaft.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3391.jpg

After this put the pressure plate on being sure to put the lifter in it first (It really only fits in one way) and then you can put your clutch springs on. For the clutch springs there is no torque value they give so just bottom them out and then tighten JUST A HARE PAST THAT, NOT MUCH AT ALL OR YOU WILL BREAK THEM!! By just a hare i mean like 7 ft pounds max! after that your done with the clutch

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3392.jpg

As for the flywheel side im sorry but I lost most the pics (no idea how) but I do have one important one. MAKE SURE before the starter gear and flywheel go on, which should have come off as 1 piece anyway, make sure your woodruff key is in place and put the thick spacer and bearing on the shaft and then slide the starter gear.flywheel on and bolt it in place.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3379.jpg

[rubbersdown]

After the flywheel is on I usually put the piston and cylinder on. Now I didnt get any really good pics of this as i was alone doing it and it kind of takes 2 hands and i had no one to take pics but the easiest way I find is to just slide the piston on, put the oiled pin threw and use a pic set to put the circlips in place. I did not do a write up on putting the rings on the piston as they were already on my piston sorry. Once the piston is on I slide the cylinder over top the piston letting it slightly rest on the top ring, I then push the rings together with my fingers one at a time and let the weight of the cylinder do the work. BEFORE you do this though make sure you put a new base gasket on and a new o-ring on the bottom of the cylinder

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3393.jpg

Once that is on or in the process of putting it on you can fish your timing chain threw and just hold it in place with something to keep it from falling back down. Also a good time to install your other timing chain guide.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3394.jpg

Once thats done you can go ahead and bolt the head on, again fishing your timing chain threw.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3395.jpg

[rubbersdown]

After the head goes on you should install your flywheel cover and gasket, first Installing the starter gear and shaft into its spot.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3398.jpg

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3399.jpg
After the cover is on set the motor to TDC by turning the motor counterclockwise with a 17mm socket on the flywheel bolt and aligning the T mark in the viewing hole. (At this point there is no compression stroke sense the cam is not in so just align the T and your good) http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3400.jpg
Once your at TDC take your cam sprocket (sprocket only) and put it "into" the timing chain so that the 2 lines are even with the deck of the head then slide your cam/bearings thew and bolt the sprocket to the cam. Once the cam is in make sure your 2 bearing setting pins are in place to.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3401.jpg

your timing is now set. you can now put on your valve cover and bolt it into place, put on your tensioner and check your valve clearance. I did not get any pics of my checking the valve clearance but its very easy. Just put the motor back at TDC this time on the compression stroke and take the timing caps off. The valve clearance per the honda manual is .10 intake and .12 exhaust. You just loosen the lock nut, unscrew the little screw a bit and put the appropriate feeler gauge between the screw and sub rocker and tighten the little screw till there is a little drag on the feeler gauge then tighten the lock nut and double check with the feeler gauge, if there is a little drag on it your done, move on to the next one. When all of them are done you should rotate the motor a couple revolutions and then put it back at TDC and re-check them just to be sure.

[rubbersdown]

Now you can work on the starter. Put the other starter gear and shaft in place like so, with the thick washer on the outside, the push your starter threw and bolt it in place and put the cover on, now thats done...

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3403.jpg

After that you can go ahead and put the clutch cover on. Only thing here is to turn the clutch shaft A LITTLE counterclockwise so that when you put the cover on it grabs the lifter and engages into the rod.
Well, thats pretty much all there is to it. Not to bad right?! now go out there and put your own motors together, its really not that hard!

FINISHED...
http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3404.jpg

[rubbersdown]

OK GUYS IM DONE. lol. I have never done a write up like this before so take it easy on me. im sure I forgot to say something or left out something you consider important so feel free to add whatever you want. I just wanted to show that its not to hard to build a motor and hopefully someone will learn something from this and it will help someone out. Also, I did this VERY fast so im sure there is lots of typos and spelling errors, I will try and go threw it and fix them at a later point lol.

[99RED4X4]

Like it. So the bottom end of the motor is really THAT SIMPLE??????

Transmissions always scare people, including me, but from your pictures it looks like its pretty simple...

[IMSROLL450R]

Sweet man great job. Ya made it look easy.

[rubbersdown]

Originally posted by 99RED4X4
Like it. So the bottom end of the motor is really THAT SIMPLE??????

Transmissions always scare people, including me, but from your pictures it looks like its pretty simple...

It really is that simple. If you take it out to replace the crank you can just take it out as a unit and install it all as a unit and never touch a thing. BUT even if you do mix it up it is super easy to put all back together. just follow the schematic and take your time. Each gear is different then the other so its pretty hard to mix them up. That is the kind of response I was looking for, people to realize how easy it actually is to rebuild these motors. and once you have done one 4 stroke they pretty much all look the same minus some cooling aspects of a liquid cooled motor.

[rubbersdown]

Originally posted by IMSROLL450R
Sweet man great job. Ya made it look easy.

Haha thanks, thats what I was trying to do because it really is just like most hot girls, easy but intimidating.

[honda400ex2003]

Looks great! The only thing that may helpful would be to embed the pics instead of having links. Maybe it is just my machine though since i am using chrome. ? Cheers to a job well done! steve

[rubbersdown]

Originally posted by honda400ex2003
Looks great! The only thing that may helpful would be to embed the pics instead of having links. Maybe it is just my machine though since i am using chrome. ? Cheers to a job well done! steve

that is how I wanted to do it but it didnt work for some reason. I clicked the img button and embeded the link to the pic like i always do and it usually shows the pic not a link but for some reason only the links showed up this time and not the pics, maybe a moderator can fix it?

[honda400ex2003]

its possible they might lol oh well it is only a few clicks more. lol steve

[99RED4X4]

it really is just like most hot girls, easy but intimidating.



Nice!

[smorris1]

greatest step by step ever! hahah

[rubbersdown]

Originally posted by smorris1
greatest step by step ever! hahah

lol thanks, maybe i can talk a mod into making it a sticky. Ive never had my very own sticky! lol.

[Racerjames]

Good deal! Very informative write up for those who fear the "big bad bottom end".
The only thing I could think to add is when you are doing your valve adjustments, when you are done, turn the motor over a couple times and just re-check the tolerances to be doubly sure.

[rubbersdown]

Originally posted by Racerjames
Good deal! Very informative write up for those who fear the "big bad bottom end".
The only thing I could think to add is when you are doing your valve adjustments, when you are done, turn the motor over a couple times and just re-check the tolerances to be doubly sure.

Good idea, ill edit and add that.

[NacsMXer]

Originally posted by rubbersdown
that is how I wanted to do it but it didnt work for some reason. I clicked the img button and embeded the link to the pic like i always do and it usually shows the pic not a link but for some reason only the links showed up this time and not the pics, maybe a moderator can fix it?

This is a FANTASTIC write up, very informative thank you. :)

Photobucket links don't like to work when you use the "ATVriders IMG" button and paste the link for some reason. It is easy to fix though.

Just go into your actual Photobucket album. Mouse over each thumbnail of the photos and you will see a bunch of options below it pop up. Such as "Email & IM, Direct Link, IMG code", etc.

Simply copy and paste the IMG code directly to your ATVriders post, and that's it. Don't use the ATVriders IMG button or anything. Should fix it, and would make the write up a lot easier to read.

Thanks again.

[rubbersdown]

That worked perfect, got the actual images on there now instead of links. THANKS!


Originally posted by NacsMXer
This is a FANTASTIC write up, very informative thank you. :)

Photobucket links don't like to work when you use the "ATVriders IMG" button and paste the link for some reason. It is easy to fix though.

Just go into your actual Photobucket album. Mouse over each thumbnail of the photos and you will see a bunch of options below it pop up. Such as "Email & IM, Direct Link, IMG code", etc.

Simply copy and paste the IMG code directly to your ATVriders post, and that's it. Don't use the ATVriders IMG button or anything. Should fix it, and would make the write up a lot easier to read.

Thanks again.

[MtnEX]

One of the best threads I have ever seen on here!

Ain't Skeerd no more...

Nice writeup... nice to "see" it done before doing it yourself.

[rubbersdown]

Thanks buddy, I buy blown up bikes and rebuild them and sell them for $ all the time. I usually do motorcycles but from now on if I get a quad im going to try and do a build thread like this for every dif quad I do just to help out my forum peeps.


Originally posted by MtnEX
One of the best threads I have ever seen on here!

Ain't Skeerd no more...

Nice writeup... nice to "see" it done before doing it yourself.

[NacsMXer]

Glad it worked rubbersdown :)

I think it's sticky time for this thread! :D

[Honda#4]

One of the best rebuild threads I've seen, makes me feel better about a bottom end rebuild thats for sure.

Great job Rubbersdown.

[tri5ron]

Good Job, and nice write-up.

The only thing I would add is the importance of Proper Torqueing Proceedures.

Cleaning all Casebolts, Side cover bolts, and all of the threaded holes that they go into.
Also to elaborate on the importance of using a properly set torque wrench, and proper torque proceedures/sequences..

All of this to help to avoid stripping any threaded holes, or snapping any bolts.
(it seems to be a common issue/occurance, with many of the less experienced members here).

Great job, It will surely be a benefit to many.

[Racerjames]

OOh OOh that reminds me!!

If you are torquing to spec, be sure there is no oil down in the bottom of a bolt hole, it will throw your torque values way off and can contribute to things coming apart by themselves

[bkb88]

How about putting together a list of specific specialty tools used & a few pictures of tools required? This is an invaluable source of info for anyone wanting to do a full overhaul!

[rubbersdown]

Originally posted by bkb88
How about putting together a list of specific specialty tools used & a few pictures of tools required? This is an invaluable source of info for anyone wanting to do a full overhaul!

There really are no specialty tools required except for a flywheel puller if your taking it apart and you can get that on ebay for like $10. You dont need a case splitter and you can sweat in the crank and bearings with a freezer and either a torch or an oven so you dont have to have a press. Its really just sockets, wrenches, screwdrivers and a torque wrench. ntn special really.

[bkb88]

Thank you for clearing that up! Definitely feeling more confident about rebuilding a 4-stroke bottom end if the time ever comes.

[Scro]

I added a link to the "Popular threads" sticky.

[rubbersdown]

Originally posted by Scro
I added a link to the "Popular threads" sticky.

Sweet, im stickied!
thanks

[Ian400ex]

Thanks for this, it's always nice to SEE what you are going to do.

[400exmxrider15]

What do you use loctite thread locker on?

[gbettner]

I just did a complete top and bottom end rebuild as a side job for some kid who toasted his motor using ONLY this sticky thread. It runs great with no issues. Thanks for such a helpful informative thread, you've really helped me out a ton!

[2001400exrida]

great write up!

I wish i would have had access to this when i was doing my build.

The only point i will make is to be sure to put locktite on the cam sprocket screws. One of my screws fell out while running and it caused all sorts of havoc!

1 head, valve cover, and cam chain later, and i'm back up and running, but it was an expensive lesson, lol.