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RKDad

2003 400EX custom

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I recently picked this quad up and upon inspection found it had some unique custom work. I'll post some pics of the most obvious mods and see what you think. I'm still laughing at what I'm finding as I tear down further. The 1st picture is the custom table cloth seat cover. 2nd is the custom pull start. 3rd is what seems to be the battery box. 4th and well my favorite, custom battery relocation and filter delete. Guess they figured it needed more minerals or just increased air flow. Did you happen to see the custom battery connector? Priceless! Not to mention all the wood screws holding plastics and some red lights installed in the frame. And finally, for this discussion, tilt steering. The steering rod is bent back right at the top clamp almost resting on the tank. 

Now it does run and drive after ingesting large amounts of dirt. It does knock louder than the landlord on rent day though. 

They were asking 1500 and I handed them 800 and they accepted. The only reason I bought it was because I knew parts were available and fairly cheap. 

What do you think? Good or bad deal. 

RKDad

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Well I can say you have a unique 400EX...lol  Hey if it runs and drives I would say you did pretty well....always a plus..

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Thanks, I definately have my work cut out for me, but I do rather enjoy it. Especially after trying to find parts for my 85 XR350R. Parts wharehouses were on the coast of Japan and were destroyed in the tsunami's. Being produced for only one year there are no major motor or carb parts. 

RK

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wow! yeah it's customized.... as for the price, i couldn't say.... but curious to what other custom mods you come accros. i would seek out @SlammedRanger 

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Thanks Wilson,  I did notice one thing, looks like it's a little rich on the dirt if I'm reading this plug correctly.

Other than a lot of weight reduction in the form of missing bolts. Wishing I would've bought this before we redid our front deck,  I wouldn't have had to buy as many wood screws. Lol  

I'm so anxious to tear into the motor but need to finish my work shed first.  Oh and when shifting gears you push into gear and after you release it you hear the click. There's a slight pause like it sticks then goes into gear. Again I'm suspecting a little to much dirt. Oh well, in these times we all need a good laugh.

 

RK

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your welcome, and yeah I'm with you, i honestly do think you have your work cut out for you, the socket spacer on the battery post really got me, because i have seen that done before this post, lets just hope the socket was a china made, but it looks like a craftmans socket...... i don't mean any disrespect .... but the mods they did are funny, but it  runs! so plus plus... and the tow rope on the front is for pulling this machine off ? you have to give them credit for the battery in the air box thats a new one on me, it and the missing air filter might ?? explain the disfigured spark plug. 

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That is indeed the custom pull start. I'm afraid the motor is full of dirt, or enough to take out the rod bearing for sure. Weird thing was when I drained the oil, the oil tank plug was covered in dirt and sediment. The crank plug wasn't.

 

I am so resisting the urge to take the top end off until the shed is finished, but I'm feeling weaker all the time.  We'll see, I might just to peek..

 

RK

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Well I had to Peek and I'm a little confused. It was everything I expected until I removed the cylinder. 

The cam was absolutely smoked, if you look on the middle journal you see shavings against the cam, they are welded. Had to tap it with a hammer and punch to break it off after I got the cam out.

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Removed the valve cover and inspected the lifters, yep, just as bad. Complete loss, the journals are wasted as well. 

 

RK

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This head as well will join the pile of paper weights. Valves and guides are so wore that you can wiggle them from side to side. I will keep the springs as spares if they're still in spec.

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Check out the debris on top of the piston. I believe they are pine needles. Unbelievable!! Now the interesting part, I'm figuring rings are wiped and cylinder would be scratched beyond belief. But not so, in fact the piston and rings look OK and the cylinder walls are as smooth as a babies behind and barely any ridge at top of cylinder and its mostly the same crap thats on the piston. 

 

With the amount of noise this thing made when it fired it startled me so bad that I couldn't shut the engine off fast enough. So naturally I'm expecting the rod to have ALOT of free play. But in fact there is zero lash up and down and I tried it in every position on the crank. That's where I was standing there scratching my head. There is a little more side wiggle than normal but it's little enough I wouldn't worry. 

Now I didn't notice the wrist pin when I was removing the piston and after another look I noticed the burned ring in the pin. So I reinstalled the piston and it had so much side to side and if you put your fingers on the ends of the piston and rock it back and forth its like a bobble head. There seems to have been alot of heat on the crank as you can clearly see the blue color. Con rod does have one spot you can feel slight drag other than that its like butter. Either way a new bottom end is going to be installed. Once the flywheel puller and case splitter get here I'll dive a little deeper into it. 

 

RK

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Looks to me like the rings or valve guide seals were leaking oil into the cylinder , till the engine got so low that it cause damage to the wrist pin , connecting rod journal , cam and cam journals 

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8 hours ago, RKDad said:

Check out the debris on top of the piston. I believe they are pine needles.

 

hard to believe a pine needle would make that trip....wow, be sure to keep us updated, and please don't tell the PO about this place..lol! we don't care for people that abuse machines that much...... i did notice the exhaust right out of the engine looked like it was oil coated. i can honestly say i feel for this machine. looks like a complete engine build unless your planning on flipping it ? 

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2 hours ago, Fishfiles said:

Looks to me like the rings or valve guide seals were leaking oil into the cylinder , till the engine got so low that it cause damage to the wrist pin , connecting rod journal , cam and cam journals 

Definitely didn't have enough oil. It had about a quart in it when I drained it. The main cause was the dirt ingested. I was told they removed the filter because ridding through swamps it would get the filter wet and die. And they live on a dirt road to. 

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2 hours ago, _Wilson_™ said:

 

hard to believe a pine needle would make that trip....wow, be sure to keep us updated, and please don't tell the PO about this place..lol! we don't care for people that abuse machines that much...... i did notice the exhaust right out of the engine looked like it was oil coated. i can honestly say i feel for this machine. looks like a complete engine build unless your planning on flipping it ? 

I do plan on keeping it so I'll put the money into it since I got it cheap enough. Saddest part was when I left from picking it up, they actually had 2 of them. Was like taking a puppy from it's mother. The other one wasn't quite as bad, it only had a slight knock, but they said the guy did some engine work himself to make it faster. After seeing the way they were both taken care of I offered them $1500 for both. 

 

Well going to wait for some tools to arrive so I should be back in a few days with an update unless I find something else amazing, lol. 

 

RK

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i like your attitude..... lol! especially about the wood screws, and seat cover. 

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Thanks Wilson, I'm a litlle more giddy than anything. I waited 36yrs to get my childhood dream bike. This is kind of like that. One I always wanted but could never afford. Except unlike my XR350  which I change oil after every ride, about 60 miles. And parts are all but non existent. This I can ride the snot out of and enjoy it. With the air filter on. 

 

RK

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your welcome..... i was kind of the same when i purchased my 1st atv an 85 fourtrax 250..... spent alot time riding that bike, I'd like to have another to go with what i have now... chances of finding one are slim, and and one in good shape .... almost impossible... anyways  how's the repair going @RKDad

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Hello Wilson, Just got my tools a couple days ago so I will be yanking the crank today hopefully. Just need to take clutch side apart. Then it's off to Dr Crank Shaft for rebuild. Instead of trying to find one that doesn't cost more than the bike, figured it to be the best option. 

Now I'm finishing my coffee waiting for the sun to come up and warm things up a bit so I can get at it. 

 

I have a couple vehicles i've sold over the years that I wish I could get back. Always wonder, what's a fella thinking when he sales his favorite toys. Probably, I wish I knew how much I'd miss it and kept it. 

 

Thanks

RK

 

 

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1 hour ago, RKDad said:

I have a couple vehicles i've sold over the years that I wish I could get back. Always wonder, what's a fella thinking when he sales his favorite toys. Probably, I wish I knew how much I'd miss it and kept it.

 

i can relate completely ..... lol. 

 

be sure to keep updated on this refresh. 

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I would bet my last dollar the crank is completely fine. The blue on the rod is 100% normal. If there was no up and down play in the big end it would be good to go. Your knocking i would almost guarantee was a stretched timing chain. While you are doing this rebuild i suggest doing the crf450r timing chain upgrade. Requires no modification but is alot stronger then the factory chain. If you have any questions feel free to hit me up! I have alot of custom mods done to my quad aswell. But not that type of custom lol

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1 hour ago, SlammedRanger said:

I would bet my last dollar the crank is completely fine. The blue on the rod is 100% normal. If there was no up and down play in the big end it would be good to go. Your knocking i would almost guarantee was a stretched timing chain. While you are doing this rebuild i suggest doing the crf450r timing chain upgrade. Requires no modification but is alot stronger then the factory chain. If you have any questions feel free to hit me up! I have alot of custom mods done to my quad aswell. But not that type of custom lol

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You definitely would keep your money on that one. After I looked at it closer the other day I noticed the crank had no color at all. It has maybe 25% more side to side and zero around the crank. Have to send it in to get a new rod as the wrist did a number on it. I think the cam chain is good. I used a little tool I made to count how many turns it takes to pull the tensioner all the way in. Then installed it and rotated the motor a few turns then checked how many turns it took to retract the tensioner. 9 1/2 turns from full extension and only 6 1/6 off cam chain. Seemed to have plenty of adjustment left and the guides look almost new. It felt good, but when I took it out there are 2 link that bind pretty badly even after trying to loosen it up in and ultra sonic cleaner using 50/50 simple green/water. So I will be looking for a new chain regardless. Thanks for the part number, going to get on that. 

 

Not sure on the cylinder yet. It's going to need honed out to see how much it will need to be bored. I want to stay in OEM spec for now and ride it that way next summer before changing thing up a little. Some before and after stuff. If I understood correctly I can go .025 over bore and still be able to use oem size piston? Should be getting a hone in a few days so I can see after I spend some time on it

 

I got a few pics of progress so far. I will put them up as soon as I get home tonight. 

 

Thanks

RK 

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Well here's  progress so far.  I got the case split and everything out. I have to admit, I thought the motor would've been in worse shape than it is. Bearings are all in great shape, most damage seems to be in the top end. Think I'm going to take cylinder to a local shop and have them hone it. I have a hunch it's beyond oem spec. If so I will keep it for when I put a bore kit in it. Sending out crank today for a refresh.

 

The oil tank and cooler are next on the list. The tank was full of dirt and metal so I'm sure the cooler is packed. I used kerosene in the tank and it cleaned it right out. My ultra sonic cleaner isn't big enough to put he oil cooler in so I'll fill it with kerosene and let it sit then blow out and see how it works.  

 

RK

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thanks for the update, i take you've not run into anymore hacks ?? I'm not an expert by any means, but i think a complete refresh on this one is a great idea being this is your dream bike. 

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Fortunately no more hacks, other than a pair of 6" bolts they used on the front top shock mount. They must've had trouble with the little filter in the carb as well because it's gone. I could only imagine what the other quad looked like. They actually "modded" it for more power. It did run better, by that I mean it didn't knock as loud. Lol it was in better shape but knowing they were inside that motor was enough for me. It was a newer model with the cut (narrower) fenders. Both had the same visual mods though. 

Well gotta get out and get the wirring and steering stem off then a deep clean to really check the frame for damage. Will post if I find anything.

 

RK

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