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Hey guys, so I have been doing some work on a project I am working on and have recently put it back together and took it for a test ride. To start the bike I only used a battery but since I did not have a place to keep the battery (XR400 Frame) I did not keep it wired in the system. From what I have found out this may have caused my starting issue I now have (No spark). The bike is getting fuel and the battery is fully charged. So my guess is that from running without a battery I may have shorted out some of the electrical components though I am not sure which ones to check first and how to check them. I know I should check the stator, regulator/rectifier, and the CDI but I am not sure if one would be a better place to start over the others...my theory is to start with the cheap fixes first but it would be great to just figure it out first and then just replace what needs to be replaced. Any help is appreciated!

Hi, im pretty new to the forums so im going to introducw myself. Im brandon and i am confused what i should get. I am 5'2 and in the 140-150 pounds and pretty experienced with four wheelers and dirt bikes. My question is would i be able play around on something like a stock yfz 450 without having to constantly be up on it making sure it wouldnt flip. Would i be able to handle the power/tourqe while being able to mess around and have fun?

So my 2007 trx400ex's brake pedal has seized in frame. How to get it unstuck?. I have been confused about this for quite a while

I have a 2005 honda 400ex thats been bored to a 440 with a stock cam, valves are set just right I have tried from a 150-175 main jet and from a 38 to a 45 pilot I cant get the thing to idle for the life of me, it seems like it wants to turn over whenever i hold the throttle wide open, i got it to turn over once and idle, when it did idle it seemed fine,my question is whenever i hold the throttle wide open am I pushing gas into in or leaning it out since im holding it wide open also I have the choke open while trying to start, ive tried to choke it and it doesnt sound like it wants to kick over. The carb is literally brand new and ive blown compressed air through it multiple times, compression is at 100 psi with valves sitting at .004in/.005ex brand new oem honda filter,brand new spark plug, brand new gas coil is getting a nice blue/white spark, all of the airboots are tightened down good, ive cleaned every single ground on the bike and has a new starter, I know ive made this long but does it have to do with me utilizing the stock cam with such a big bore? im stumped and i need this bike to run, I dont know if slammedranger is on this website but i really need a 400ex guy also dont have the decompression mechanism on the cam itself with the spring and detent removed from the head

I have a 400ex that I am looking to get a battery for and I am wondering what batteries out there would last the best and are the most reliable...I am interested in the antigravity batteries because of the size and weight reductions and since this is a somewhat custom build...those would be most ideal for this application..but does anyone know of other good reputable batteries or have experience with these antigravity batteries?

Alright guys, so I am new here so before I get started I just wanted to make a few opening remarks... *If this post is in the wrong section I apologize and if it's possible to move please do so and I know this topic has been brought up before somewhere but I can not find it so here it is again...and hopefully gives more information on this build. Also if anyone has questions about this ongoing project I should be able to answer them. The reason I have decided to finally make this post is because I have finally got it all buttoned up (engine wise) and seems to be running well...aside from a few complications which maybe some of you can help out with. Lastly, my apologies for the long post I felt that I should include most things I did because in my own research, this project is not talked about much at all it seems. So here it is, I have been working on this project for around 5-6 months now and, mind you, it started as a basket case so it doesn't look great cosmetically by any means and most of the plastics are either gone or damaged but mechanically, all parts appear to be there and it working condition. What I have done is exactly what the title says, placed a 400EX engine into an XR400 frame. Now, most people that do this start with the XR400 and find a 400EX engine to put in, but I was given a frame and engine with a buck of extra bolts, nuts and clamps. After two years of sitting in my basement I decided to test if the engine turned over, great news, it did. SO, that motivated me to put it in the frame and it DOES fit, but the bottom frame mount is too far up to be used, but with three other mounts tightened down, it was fine. BAD IDEA, turns out the engine had ZERO compression and needed a new top end because whoever had it last put the piston in backwards and bent the intake valves. After a couple weeks I found the time to get the engine bored out 1mm over and changed the valves. *REBUILD* Got the 400EX taken apart and slowly starting to find the issues associated to ZERO compression According to the piston, two intake valves were coming in contact with the piston itself, luckily this appeared to be a fresh rebuild...otherwise it may have detonated and caused many other issues.. And just as expected...bent intake valves...which mean possible cracked or damaged valve stems... Clearly, these are the culprit for no compression...to the left is the PVC pipe valve spring compressor I used to get the valves out, but not in I will show that tool later on. Further investigation revealed build up of some sort on the piston wall, so after attempting to hone this away I quit and took it to get it bored out. Knowing that I had bent the valves, I decided it was best to check the timing chain and low and behold...it was slapping all over the place inside the case when it "started" for the first time I assume... Removed both inner and out clutch baskets, oil pump gear and drive gear to get to chain and found out that the oil pump does not need to be removed to get to the chain(rookie mistake) and also discovered that the springs behind the outer clutch basket move freely which is not what they are supposed to do I am guessing...so that will be replaced. New chain in and clutch baskets are torqued back down with a new piston on top...another rookie mistake...make sure to put the piston on BEFORE putting the jug back on...yeah felt like an idiot after I did that... Very hard to tell but from my measurements...the original chain(left) was stretched by half a link I believe Also found out that at some point the crank was replaced....just hope that whoever put the piston in backwards didn't do anything wrong here... Seated new valves(ended up going back through a few more times after I took this picture) Valves and springs put back in the head and retaining clips in...I'd like to think I saved myself some money by making a compressor tool in the upper right corner Used a clamp and I duct taped a copper crush washer on the other end to help protect the head....the thinking was that the copper would dent before anything else would And finally all back together...but keep in mind this motor still hasn't been started in 4 years at the least.... **Starting** 1/15/17 Bike officially started today, but it is really cold here so it was running lean with a high idle and slight back fire when revving...will try again when weather warms up... 2/19/17 Had a nice 50 degree day and decided to take it out and try to start it again and she still comes to life...but the idle was still high in this video...I was able to get it adjusted to a nice even idle....the only problem was that it had to be at full choke...vacuum leak? I figured since I am running an XR400 carb right now it probably won't run the best anyway...but full choke shouldn't be necessary regardless...if anyone has any tips or suggests feel free to let me know...willing to try out other carbs without the insane price tags.. Of the four available engine mounting locations on the XR400 frame(I think) I only used three but have plans to move the bottom one down to put that to use.. Closing remarks This is my first post and I did learn a significant amount in the process but keep in mind this is by no means complete so I will still be figuring more things out as I go...and as I said I have not many posts...(one really) about this project being done and the details of fitment. The most I saw were people guessing that it would not be possible to fit this machine, but I believe that I can say it is "fitted" now but a few more kinks just need to be straightened out...other than that I am looking forward to finishing it up and going for a ride...one day!

Hi, my 400ex when i go to start it the starter just kind of spins and doesnt engage. I mean ever once in a while it will kinda catch but it isnt working right and i dont know how to fix it

Hi i've been riding a 400ex with a 440 kit in it and fmf powerbomb headers in it. and i wanna sell it and buy a dirtbike and i wanna get a yz125 but i have no experience with 2-strokes. I guess my question is do you guys think i can handle it? Oh yeah, if you think i cant handle the yz125 i would really like to get a 2-stroke dirtbike so if there is an alternative let me know. I am 13 years old 5,6

Just picked up a 2004 400 ex for 500$. As I got it home and was looking I found this random wire hanging down, (circled in red) it obviously doesn’t go there and was wondering what the heck it is? Also the spot circled in green there’s a little bit of exposed wire, is this a problem when washing? Is there anything I should know before washing the bike?

First 400 EX I've ever bought it's an 02 with newer plastics and suspension upgrades. I've heard all four hundreds tick some . Dose mine sounds ok . Haven't changed oil yet / just got her https://youtu.be/BGvNm98riyI

Hey guys, I got a 08 400ex and while I sent my motor off to get an entire stock rebuild with alittle bit of valve porting. Once I get this thing back together I’m going to have a lot to consider on how to make it run smooth. I just want simple and least harmful for the engine. I have a brand new big gun revo r exhaust system, (header pipes and silencer)theyre an oversized headers pipes I assume so there’s more airflow yadda yadda. -Airbox lid on/off? -Stock Snorkel on/off? Should it be blanked off if no snorkel? -Needle position? -Preferred jetting? -Air/Fuel mixture I don’t know I’m new to this bike and don’t want to ruin a reliable Honda, just give er a little spice! Thanks, Kodie

Hi, I have a 2004 trx400ex that has weak and sometimes no spark when trying to start it. When I hook it up to a charger to get it to crank faster, it has strong spark and will start. I tested the resistance through the stator and pickup, and it seems fine but I couldn't find the ohm specs anywhere online. I switched out the CDI with another one but that didn't change anything. I also tested resistance through the coil and cap, but like the stator, I couldn't find any ohm specs online- just the "peak voltage" specs which I don't have the means to test. This problem has been happening since I got the bike (5-6 years) but it has never been this bad. Any suggestions or ohm specifications are appreciated. (P.S. When it does run, it runs badly. I think I have some jetting issues to work out but, it could also be partly caused by the same electrical issues.)

I'm looking for the best reliable atv for trail riding, the main thing I'm looking for is extremely low maintinance and I'm looking for the sport style atv, not the utility styled atvs. Don't really care about engine size just care that the quad fits me at 6'1, and won't get boring. Also looking for good reliability along with the low maintinance.

I am looking at getting a new exhaust system and I have came across Empire Industries exhausts systems and I really love the design and the way it looks and sounds. Does anyone know anything about them/would recommend them? I really like everything about them and would like to know if it is a good brand, thanks.(here is a image with my top 3 designs that they offer)

Hello, I am 15 years old and I recently bought a 2004 honda 400ex back in July, in terms of engine wise it is bone stock, I have put nerf bars and some new protaper handle bars and a graphics kit, I am looking to get a full exhausts system. I was looking for any suggestions that would give a good increase in power and sound/look really good. My budget is currently 400 to 500 dollars but will hopefully go up alittle after Christmas. I am also looking to get some info about what else I will have to do after getting a exhaust system, like what size jets would work best and anything else that I would need to do. I do not know everything mechanically wise, but I would say I know alittle more then average, thanks for your help.(I added a few photos if anyone wanted to see the bike)

Hi all, I took apart my 400ex clutch today and the thickness of the plates is .116 give or take a .001. Are the plates in spec? The reason I ask is that when ever I started up my EX, it would jump when I put it in gear (with the lever pulled of course) and would not go into neutral until fully warmed up. I think I have a Barnett clutch but might be mistaken (first time taking apart the clutch). Also would the Tusk clutch kit be a good replacement if the one I got is done? I mostly ride trails. 2004 400ex mega-bomb header, Q4 muffler, k&n air filter, 10-1 wiseco stock bore piston

Just bought a 01 400ex with title for $400. Turns over. Wiring is a mess but came with a new oem coil, and a whole wire harness with light wires (oem). It doesn’t have spark but does turn over with good compression. Where should I start ? Another question is, is there any 2 stroke motors that would be easy to throw in it ?

So my 2007 trx400ex's brake pedal has seized in frame. How to get it unstuck?. I have been confused about this for quite a while

Just rebuilt a 400ex and found out, once I took the outer clutch basket off, that the springs on the backside of it are loose and can move freely inside the hub assembly itself. This, to the best of my knowledge, isn't normal but what might this cause in regard to clutch issues? Is it still useable or should I find a replacement? These are the little springs I am talking about.

so i love the yamaha banshee the way it looks and stuff but dont really want all the power that comes with it. so what im thinking for my first quad i wanna put a 400ex engine which is more docile in the yamaha banshee. i know its not gonna be easy but thats what i wanna do. what do you guys think? im 17 120ibs 5'10. btw im new here

Hey, I'm looking for a faster cranking starter for my 400ex and was wondering if anyone here is using a DB Electrical starter? And if it actually cranks faster? Also, does anyone have any recommendations for any other starters that crank faster for a 400ex? And what is the best battery to use too? Thanks.

I’m building a bike that I wish Honda would have done. The bike is a CRF450 chassis with a 400ex engine. Basically an XR400 with electric start. My question is, “How much oil does this motor pump out, up to the frame, in a given minute?” Short of just pulling the line off and starting the bike and watching to see how fast it can fill a quart bottle. Does anyone know? Reason for asking this question is because I’m building oil tanks in place of the wet frame that was found on the XR400 bikes. With the two tanks that I’m placing on the CRF450 frame in place of the radiators; I need to do a cross over from one tank to the other. I would like to run the bike with both tanks more or less full, in order to take advantage of the most cooling I can get. I just don’t want to starve the engine for oil waiting for one tank to fill up to a high cross over. On the other hand I don’t want a low cross over and lose out on the cooling ability of the tanks if they’re going to be mostly empty while the bike is running. Does anyone have a realistic idea on how to get a cross flow effect without taking forever to get oil to the return line? A few videos can be found of it on YouTube under “XR400AF” if you care to watch them and give me any ideas for oil line/tank. Thanks in advance for any help.