400 project build

[matt400g12]

Bought a 2005 400ex for $1000 in need of complete engine rebuild. Just thought I'd start a thread of my progress over next month of rebuilding it! :D

http://i579.photobucket.com/albums/ss235/mattgx2012/400.jpg (http://s579.photobucket.com/user/mattgx2012/media/400.jpg.html)

http://i579.photobucket.com/albums/ss235/mattgx2012/20131025_121518.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131025_121518.jpg.html)

[matt400g12]

http://i579.photobucket.com/albums/ss235/mattgx2012/piston.jpg (http://s579.photobucket.com/user/mattgx2012/media/piston.jpg.html)
Believe it or not...it ran in this condition. I had no idea what was going on in the engine until I thought about it and started tearing down the top end. VIDEO:
https://www.youtube.com/watch?v=lzJHnEHeZ_U

This is a breakdown of what my plans are:
-#1 I have to get that freakin swingarm pivot bolt out!! I might have to take it to the dealership cause I don't wanna make it worse
-Replace headlight (the mounts were broken and I found woodscrews through the bottom)
-I sent the cylinder in to get bored out a millimeter, and ordered a wiseco piston to match it
-I've got a hotrods heavy duty crankshaft and main bearings on order as well (hoping it will outlast the oem one, which I'm sure it will)
-Replace timing chain as preventative maintenance. Might as well while I got it apart
-Gotta split the cases, obviously, and clear out all the piston pieces!
-Fix er up cosmetically (bumper, seat cover, plastics, graphics)
-Get new wheels and new front tires (one of the front tires is stock and the other is basically a brand new carlysle trail wolf)
-Various other fixes (Clean carb, clean head, valves)

[Fix29]

I bought a parts bike last month and the piston looked almost exactly the same. I found the missing piece of the piston skirt in the bottom end lol.

[Exrider911]

Can't believe that thing still ran lol those 400ex are crazy reliable..:muscle:

[RNL]

Good thread, look forward to your progress.

[Blodg]

Fix29 or Matt, any idea what caused the piston damage in those motors? And yes it is hard to believe it ran like that!

[beastlywarrior]

High head, high revving and brittle cast pistons

[Fix29]

When I took the motor apart it appeared to me that the oil pump may have quit working.

[matt400g12]

yeah those cast pistons are no good. I ran wiseco in all my bikes and never had a problem with them

[matt400g12]

UPDATE:
I took the whole quad to the dealership to get the swingarm pivot bolt out. I do not have the time or tools to get it done especially living in an air force dorm. But if you can spare $100 have a shop do it cause it will prevent a lot of possible issues. This has been the only thing keeping me from doing anything so the project can finally move on.

First thing I did was I removed the engine and stuck it on the floor in my truck. Then I put all the plastics on for transport. I'm separating from the air force, so it's going up north to Michigan in a week or 2. Plus all my specialty tools are there :D

The cylinder is currently being sent out to be bored out to 86mm (stock being 85mm) and along with that I am getting a wiseco 86mm piston. Once I get back home to Michigan I'm going to order the new heavy duty hot rods crankshaft, main bearings, and timing chain. This is going to be a pretty slow project. I probably won't be completely done with it for another month! :mad:

The EX next to my truck

http://i579.photobucket.com/albums/ss235/mattgx2012/20131101_133822.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131101_133822.jpg.html)

engine out

http://i579.photobucket.com/albums/ss235/mattgx2012/20131101_141040.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131101_141040.jpg.html)

[Stickman400]

Bet that is a tight fit getting that engine in that Rangers floor. Mine has barely enough room for your legs, let alone a 400 engine, lol.

[matt400g12]

Bet that is a tight fit getting that engine in that Rangers floor. Mine has barely enough room for your legs, let alone a 400 engine, lol.

Hahaha yeah I had to move my seat back as far as it could!


...Another video update:
http://www.youtube.com/watch?v=hBamNWqWMPU

[RNL]

Where bouts in Michigan?

[matt400g12]

Where bouts in Michigan?

I'm from Ann Arbor area. There's places to ride an hour each direction! Cant wait to get back, theres nowhere to ride here in delaware

[matt400g12]

http://i579.photobucket.com/albums/ss235/mattgx2012/20131102_210125.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131102_210125.jpg.html)

Anybody know how to clean up the carbon buildup here? and what is up with those chips around the exhaust valves? are there pieces missing?

[matt400g12]

Well, I took out the exhaust valves. I got new Kibblewhite valves coming in on Thursday. Id rather have brand new ones than have to clean the old ones. They look too rough to re-use anyways, so here's the valves! I'll post again when the new ones come in and I have everything cleaned up

http://i579.photobucket.com/albums/ss235/mattgx2012/20131103_163707.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131103_163707.jpg.html)

[CJM]

yamaha carb dip, works REALLY well.

[Blodg]

And lot's of elbow grease to remove the carbon build-up. Mine took a lot of scraping with a plastic scraper to finally get it clean.

[MtnEX]

Talk about having second thoughts about opening mine up now... lol... 2000 vs 2005... oh boy...

[Blodg]

I should add - if you want new valves then of course there is nothing wrong with that. But I wouldn't buy new ones just because of cleaning the old ones. Cleaning the valves is very easy compared to cleaning the head. I spent hours scraping carbon off the head and only a few minutes cleaning the valves on a bench grinder with a wire wheel.

[LxMxL97]

don't forget new valve seals!

[matt400g12]

don't forget new valve seals!
almost forgot about those lol thanks for the save! I'll have to order those with everything else when I get paid in 10 days. man the anticipation :(

[LxMxL97]

When I took mine apart I almost forgot to do mine they weren't bad I just like to do a little preventive maintenance

[matt400g12]

Got the engine apart. Look at those piston pieces
http://i579.photobucket.com/albums/ss235/mattgx2012/20131105_121232.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131105_121232.jpg.html)
http://i579.photobucket.com/albums/ss235/mattgx2012/20131105_121243.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131105_121243.jpg.html)
Transmission is in great shape!
http://i579.photobucket.com/albums/ss235/mattgx2012/20131105_121238.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131105_121238.jpg.html)
Cleaned up the head a little bit
http://i579.photobucket.com/albums/ss235/mattgx2012/20131103_170620.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131103_170620.jpg.html)

[johnbanghart]

make sure you clean your oil tank filter some of that piston might have made its way to the filter and will either clog the filter or sit there and build up

[matt400g12]

make sure you clean your oil tank filter some of that piston might have made its way to the filter and will either clog the filter or sit there and build up
How do I access the oil tank filter? I haven't really got a good look at the oil tank but from what I've seen I didnt really see any kind of access point haha. Thanks!

[johnbanghart]

correct me if i,m wrong but i think there is a oil screen in the bottom hose that comes off the tank. and there is also a screen next to the oil pump with a 10mm bolt in it in side the crank case

[Stickman400]

correct me if i,m wrong but i think there is a oil screen in the bottom hose that comes off the tank. and there is also a screen next to the oil pump with a 10mm bolt in it in side the crank case

bingo

[matt400g12]

Got a bunch of stuff in the mail!
-You can see the new exhaust valves I put in the head
-Gaskets! and they came with valve seals, which is nice
-flywheel puller
-swingarm bushings
http://i579.photobucket.com/albums/ss235/mattgx2012/20131106_125443.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131106_125443.jpg.html)

everything is going together nicely
http://i579.photobucket.com/albums/ss235/mattgx2012/20131103_154613-1.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131103_154613-1.jpg.html)

[johnbanghart]

looking good bud ... not gonna lie kinda drooling over here :huh not a bad looking bike .

[matt400g12]

looking good bud ... not gonna lie kinda drooling over here :huh not a bad looking bike .

Thanks haha I'll take that as a compliment? :D but tomorrow I'll be ordering the rest of the parts, so we can get this rolling. Literally. haha
-Heavy duty Hot rods crank
-Hot rods main bearings
-New camchain
I'll have all the parts this wednesday, and I'll be working on it on wednesday and thursday, so expect a bunch of updates and pictures!
also...Got a new OEM hood, and swingarm bearings/pivot bolt in. Looks way better
http://i579.photobucket.com/albums/ss235/mattgx2012/20131107_133735.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131107_133735.jpg.html)

[johnbanghart]

Are you going to do 450r front shocks?

[matt400g12]

Are you going to do 450r front shocks?

I'll probably get around to doing that a little later. Probably around spring time. Not too big of a priority; although I heard how freakin amazing they are compared to stock. When I do get them I'm gonna have em done for my weight too.

[Blodg]

Looking good so far, thanks for the updates.

[matt400g12]

Gutted the engine. Ready for the new main bearings and crank, that's coming in tomorrow!!

http://i579.photobucket.com/albums/ss235/mattgx2012/20131112_105522.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131112_105522.jpg.html)

[matt400g12]

Also, I'm thinking of getting a 2002-2008 CRF450R camchain. I've read a few threads on it, I heard one person say it doesn't fit, and some people say that you need to replace the cam gear after a while. Anyone have any opinion on these?

[Stickman400]

The years you listed will all fit, most buy the '02 just to be certain, but I bought an '05 and it worked perfect also. They went from a 112 link chain in '08 to a 108 link in '09. I've never heard of having to replace the gear unless it's worn just from normal wear. If yours is abnormally worn or it's just an old motor then you could replace it just for peace of mind.

[lanceam24]

Matt- I'm in the same boat as you. I got an 07 a few weeks ago that ran but second gear had vanished. I tore it apart and the whole transmission was shot so I paid $100 and got a new one. My bottom end is just about done and I'll be starting on the top end today so hopefully I'll be done this week. I'm just following the "how to rebuild an engine" in the sticky. That along with the manual and it's pretty simple. Just waiting on updates from you now haha

[matt400g12]

alright guys. major problem. I heated up the main bearing, and put the crank in the freezer. tried to line up the crank with the countershaft, but the crank stuck to the bearing and now I can't get it back out to line it up properly. I am steaming right now. major frustration. what do I do

[matt400g12]

anyways...With a little tapping, I got it out and adjusted it to how it's supposed to go. Spent a while getting the transmission back in place, made sure it shifted nicely and then put the cases back together! The only thing that worries me is that the countershaft was moving from side to side a little bit...But after looking at parts diagrams I noticed I wasn't missing anything so I left it how it was and moved on. I got the piston on along with the newly bored 86mm cylinder, and I put the right side cover on. I'd do the left side cover but I'm missing one of the washers for the starter gear. I'm gonna have to look everything over again and order anything I'm missing along with that washer. I decided I was gonna use the old camchain just because if there's anything wrong with it and the engine somehow catastrophically fails I wouldn't have wasted my money haha but once I know everything is in good working order I'll get a CRF chain. heres a current pic

http://i579.photobucket.com/albums/ss235/mattgx2012/20131113_190947.jpg (http://s579.photobucket.com/user/mattgx2012/media/20131113_190947.jpg.html)

[matt400g12]

Matt- I'm in the same boat as you. I got an 07 a few weeks ago that ran but second gear had vanished. I tore it apart and the whole transmission was shot so I paid $100 and got a new one. My bottom end is just about done and I'll be starting on the top end today so hopefully I'll be done this week. I'm just following the "how to rebuild an engine" in the sticky. That along with the manual and it's pretty simple. Just waiting on updates from you now haha

haha yeah tranny work sucks. Had to do it twice on my old yz250. Surprisingly the transmission in this 400 looked absolutely perfect!

[matt400g12]

UPDATE:
I spent all night putting my motor together, then I put it in the frame this morning. Everything works great! Exept for the fact that it won't actually start...It turns over and sounds great but it's not firing. Got a new spark plug and it sparks, I don't know what the problem could be

[LxMxL97]

UPDATE:
I spent all night putting my motor together, then I put it in the frame this morning. Everything works great! Exept for the fact that it won't actually start...It turns over and sounds great but it's not firing. Got a new spark plug and it sparks, I don't know what the problem could be

your cam might be 180 degrees out of time also before you take the head off check your valves and make sure they are correct so you don't do that work for nothing

[Fix29]

I believe it will still run 180 degrees out of time. Did you stay with the stock cam? Sounds like maybe the decompression plunger that sits under it is missing.

[matt400g12]

I believe it will still run 180 degrees out of time. Did you stay with the stock cam? Sounds like maybe the decompression plunger that sits under it is missing.

It was 180 degrees off, Flipped it around and it purred. Like I've never heard a 4 stroke engine sound as nice as mine did. I'm REALLY satisfied with it. No ticks or anything. I'll have to get a video up tomorrow!

[Fix29]

Glad to hear you got it back up and running man.

[matt400g12]

Yes!!! It's great that it's running and its a huge step forward, but now I got a couple other issues to deal with. I took it to a dealership to have them put on a new idle screw, and diagnose an oil leak. They said it's leaking from the head...which is a relief. As long as it's not from the cases! ahah anyways. I don't have the time to mess with it at the moment because of all the running around I have to do from separating from the military. So when I get back home I can replace whichever gasket needs it. Also I was going to make a video but I couldn't get a good one of it idling on its own because of the idle screw situation...so once I get it back I can make one of it idling.

[matt400g12]

Update:
It was leaking oil, so I'm gonna take the top end off and do a better job of sealing it up with my extra set of gaskets. While I have the top end off, it was recommended I lap the valves (Which I should've done anyways) so I'm gonna get that all done THEN I can get a video when I'm breaking it in! In the past week, I had the carburetor rebuilt and cleaned, and a new fuel screw put in as well.

[matt400g12]

Video of it running with no leaks and everything how it should be! FINALLY!

https://www.youtube.com/watch?v=S7L39b1HNcc&feature=c4-overview-vl&list=PLwuFk0VZsfgdD-8cTcLFVvBdAdWV_oTba