420EX update

[knighttime]

Here is what the JE 416 piston looks like installed. VWVR6 and myself got the engine all put back together last night. Broken bolts were extracted and the valve springs were installed properly (the part of the valve spring with the tightly wound coils must face the combustion chamber), the timing was set, and bolts were torqued.
I was having a hell of a time installing the powerbong header pipe. But it was getting really late and I was tired, etc. But I got super lucky because I was knowingly installing it w/o the header gaskets. Well, when I got up this morning I had a treat in seeing a box from www.servicehonda.com at my front door. Yes the box contained header gaskets. :cool:
Maybe the mofo runs tonight:huh

Why was the powerbong so hard to get installed??? DId ya have your beer goggles on and they were distorting your view??:D

[knighttime]

I had everything going against me when installing it I guess. It just wouldn't go into the head. It seemed like the powerbong pipes moved after it was taken off. I'm glad though cause now I have the metal gaskets. I think it's gonna go on after work.

And I bet you can't wait ta get home and fire that sucka up.

[MOFO]

Mike,


I better see that mofo tonight up at the Beacon. :) If not, you are not allowed ONE beer until its back together...dont make me come over and hold your beer hostage. ;) I cant wait to take that SOB for a spin....



On a side note: This whole project is actually pretty easy if you take your time,have some basic hand tools and the Honda service manual (big help).

Oh and dont worry...we will line up my stock EX against this 416 and see how bad he blows my nerf bars off. ;)



Eric

So Eric how bad is this making you want to do the same thing??

I guess when you take out mikes that'll decide fer ya huh..

[MOFO]

LOL, well when he hits the start button and I dont hear any strange metal noises grinding....I'll be giving Terry a call and picking one up myself.....just kidding.

I am doing mine over the x-mas holiday. I'll be ordering the exact kit mike has....very impressed with the quality of the JE piston vs. the stock piston.



Eric

Oh,,,and mike why is it considered a 420 (hint-hint) and not a 416:D :D

[MOFO]

I think its because he drinks BUDweiser beer. :confused: :D Oh and he likes to round all his numbers up.... LOL.


Eric

Well I've also got the same exact setup from Terry to put in mine, which will start on saturday,and I almost have the same pipe setup,,aibox,,etc..so mine will be pretty close to what Mikes is,,,only difference is I got a shaved flywheel.

Oh,,,and mike why is it considered a 420 (hint-hint) and not a 416:D :D

[Stunz]

Any trick or tips on changing the valve guides?

Are your new valve guides stock 400EX replacements or did Terry recommend something else?

[knighttime]

Originally posted by Rico

Oh,,,and mike why is it considered a 420 (hint-hint) and not a 416:D :D

It's a 420EX because it SMOKES the competition.:D

[knighttime]

Originally posted by Stunz
Any trick or tips on changing the valve guides?

Are your new valve guides stock 400EX replacements or did Terry recommend something else?

The viton valve seals I installed were an upgrade from stock. And u need this tool to get to 'em. I'll make you one for cheap if you want. The tool Honda sells costs over $60.00

[Stunz]

Originally posted by knighttime


The viton valve seals I installed were an upgrade from stock. And u need this tool to get to 'em. I'll make you one for cheap if you want. The tool Honda sells costs over $60.00

Thanks, I'll see what I can do myself first, If I run into a jam, I'll take you up on your offer.

You only need this tool to compress the springs, right?

Did Terry get the valve seals for you?

Rob

[knighttime]

Yes the tool is too compress the springs. You must compress and remove the springs assembly to get to the seals.

420 BABY!

[400exdad]

:confused: Okay, if you guys have read some of my other posts you know I haven't been coming here very long. Who the heck is Terry???
Reason: You guys have got me stoked about making my 400 run better.

PS. Has anyone has had porting done at Thunder Racing or Sparks? Who have you guys had good luck with on your machine work? To be honest, I don't trust folks locally to do any machine work for me. I think most of the shops (my area) think all quads have racks and coolers and think they pull stumps with'em. Therefore, they give poor service! Just my opinion and observations.

[MOFO]

Ok first off, Terry is the guy that runs the Marcums ATV website that sponsers this site. Very good guy for info and ording parts....

Second part...from what I understand, porting your head on a mildly mod'd 400EX is not going to do anything. You are better off saving the $$$.


Eric

[400exdad]

Thanks Eric for all the info. I've just about decided to go with the JE piston (std bore) and the xr400 cam. I'm not racing of anything just having fun.

400exdad

I know I've mentoned this before because of your background with cars. When you take the head off and remove the valve springs-- look behind the valve seats. The casting quality is first rate compared to the old cast iron heads that we're used to but the machining ridges for the seat inserts can be cleaned up easily with a little pocket porting. I wouldn't pay for it but if you've got some experience-- IT'S FREE. :cool:

[400exdad]

:D Thanks for the info 2slow! Aluminum is a lot easier to port on than the old cast iron I use to have to mess with.

[400exdad]

Knighttime... tell me about your PowerCore4 Q. You just got it right? It's supposed to be quiet. Right? Is it noticeably more quiet than say a WB without the quiet core, what about with? Right now I'm running the stock pipe and love how quiet it is. However, I know at some time I may have to get a pipe to realize the full potential of the hopefully soon to be installed piston and cam.

Thanks

Oh yeah, try to keep your thumb outta that new motor! If you can!:D

[knighttime]

Well if u want excitement, get the 416/420 kit with the xr400 cam. When you have it half throttle and then goose it, well, the mofo flies; kinda like its in a ... well i hate to say it, ... but its goes into a powerband.

Happy Thanksgiving,

Mike

[kabd69667]

Hey 400exdad do you mean gt thunder or is there a thunder racing that i don't know of?? If it's gt then there porting is awesome. You won't be able to get that done for a while cuz their store burnt down. Thye are in the process of building a new one

Originally posted by knighttime
Well if u want excitement, get the 416/420 kit with the xr400 cam. When you have it half throttle and then goose it, well, the mofo flies; kinda like its in a ... well i hate to say it, ... but its goes into a powerband.

Happy Thanksgiving,

Mike

That's music to my ears.:D :D I guess I'll know come next week,,,great ta hear everything is runnin like clockwork...and yeah keep yer tumb out of it.:D

[MOFO]

Yep, i got a chance to take it for a spin last night. As soon as i touched the throttle in neutral I could tell there was a difference. Mike is right, it kinda gives it a two stroke feel. It still has all the bottom end it had before, but once she rev's up....you better be ready to shift.

Oh BTW, he already broke it in according to an very good local engine builder (the guy that bored the cylinder for him)....did the 15 min rides then complete cool down (no idle during this period)


And yes, I will be ordering this kit very soon. :)



Eric

[400exdad]

:devil When I first starting coming here, I thought: Man, just the high compression lighter weight piston will be nice. The more I read, the more I want to do it a 416 now... Maybe I'll call mine a 421 :D Just kidding.

kabd69667, I saw Thunder Racing in the article I read. Up to just a few days (before I came here) ago, I had never heard of GT Racing. Any more info on them besides a burnt down building? The article is here: http:www.atvillustrated.com/feature_articles/400exbuildup/kit2.html

Happy Turkey Day

[kabd69667]

http://www.geocities.com/gtthunder.geo/ They are located in millersburg, ohio. They make great cams. I'm sure their porting is great.

I have GT Thunder race porting on my EX. It is a major improvement. They did great work and it was a fast turn around.

My sure you have a free flowing full exhaust system or else it would be useless to even get it done.

I thought about porting on mine but Tom Carlson at TC racing said if ya ain't running a bigger carb then your pissen in the wind. The stock porting is already more than the stock carb can handle,,,ya gotta look at it this way,,,just using round numbers here......if the stock carb lets in 50 gallons of air a minute and the stock porting lets in 75 gallons of air a minute,,your already not getting full use of the stock ports,,if ya bore em bigger your still not doing anything. I just wanted to get mine cleaned up,,a simple play port is what they call it and Tom said I can do it,, it won't hurt it but I won't feel any power difference after the porting was done..so I'm leaving it alone,,I'll use the money else wear. And I'm not saying porting is a waste of money,,it's not if its done with other mods that will benefit it..

Oh and Mike will that thing do 5th gear wheelies know????

Knighttime,
did you change your jets after installing your cam and piston or was the 160 what you used before?

[knighttime]

Originally posted by mbiigamber
Knighttime,
did you change your jets after installing your cam and piston or was the 160 what you used before?

I left the jets just like they were b4 the 416 kit. You dont really want to change that after a rebuild, because you dont wanna be stalling or fighting to get it started b4 u break it in.

[knighttime]

Originally posted by Rico

Oh and Mike will that thing do 5th gear wheelies know????

Well I think it would to tell you the truth. I'll have to maybe try at camp this weekend. I dont think I have enough of a straightaway though.

Well I'm of to camp. Maybe the 420EX will be draggin' a deer. :huh