Sorry for not doing this earlier but I still don’t have internet at the house yet and doing this on a phone would cause my thumbs to detach and run off. I wanted to do a writeup of a 440 ex build that would answer a lot of questions people have that are asked repeatedly, this will include some suspension questions as well. And since I’m not doing anything crazy or out of left field I thought this would be good to do. Sooooooo……..

Just like most, I love my 400 but……Im not a small guy (210) and it could use a little more pep than it had. It was all stock internals with bigger jets, HMF performance slip on, UM airbox, 13t front sprocket, with the UM air ducts and a wrapped header. The thing was; I was happy with it to be honest but the last few times I rode I noticed some blue puffs when letting the engine brake after a long hard WOT pull. Knowing the previous owner had never been into it I knew it was time. Its a 2001; think about that, 14 years old and now its getting its first top end. So I did some reading on the 440’s and decided to go that route. Not being made out of money, I went as cheap as I could without getting junk. Here is the list…………

-440 cylinder and piston (namura 11.1 to 1) – ebay 350$
-Stage 2 hotcam – ebay 125$
-Kibble white HD valve springs and titanium retainers – ebay – 100$
-Drivetrain performance HD clutch kit with cork friction pads – drivetrain performance 50$
-Used (barely, I knocked somebody on the head for this) hinson basket and new OEM hub – ebay 80$
-CR cam chain and new chain guides and tensioner OEM – motosport 175$
-Complete engine reseal kit – motosport 30$
-Curtis sparks ignition box – Curtis sparks 150$
-OEM crank bearings – motosport 35$
-GT thunder head studs – ebay 100$
-450r carb – ebay (knocked em in the head on this one too, it was new) 80 bones
– A pile of keihin assorted jet sizes for R carb – jets r us 50$

That’s it for the engine. Seriously…..After I pulled the engine and stripped the frame I went to town on the engine. I wanted to split it to see how everything looked before I went too spendy on cranks, bearings and all that. But real talk; there was nothing in there that showed extreme wear at all!!! The only things that were worn were a few teeth in the trans but very minimal wear. The clutch basket had been gone and I knew that before all this but just lived with a grabby clutch and stiff lever. I got new crank bearings only because the manual says to replace them, but they honestly didn’t need it. The crank was pristine, I really don’t think the last owner ever really ran for more than a day or two since 01. First I went to work on the head, checked everything over, hand lapped valves, installed the HD valve springs, cleaned her up real good and done. Resealed the motor, crank bearings in, put the halves together, and started on the cylinder (the old liner was my blue smoke, she was gone!). The stud kit can be done at home but you MUST use a drill press and you MUST do EXACTLY as the instructions say or you will mess up a brand new jug. Its not bad and anybody with some good mechanical knowledge can get it done easily on their own. Assembled the piston and cylinder on the bike (they fit fine together, saw a lot of horror stories of namura pistons and "ebay" kits but I have always had good luck with them) and on went the head. Installed the cam and rocker box, cam chain and clutch, and all the covers. I run rotella T 15-40 in it and just about everything I own with a small engine, mobil delvac 3000 will do too (cat DEO 15-40).

I sent the frame off to be powder coated and once it came back, everything went back on. I replaced a bunch of hardware that was rusted and stripped out or seized, replaced the dreaded swing arm bolt (which kicked my A**!!! getting it out) and replaced almost all the connectors on the bike with deutch DT connectors. I never trust those dinky bullet connectors and hate the PITA factory connectors. I installed a second oil cooler as the weather here in southern VA in the summer stays between 90 and 100 for the most part and I do a lot of woods/trail riding so I knew cooling this pig would be crucial. I used rubber fuel line and screw clamps to tie in to the factory cooler lines for the second cooler. Its a 12×8 (I think) aluminum pro-cool unit from auto zone, it will take you for about 40 bucks and comes with the hose and clamps you need already in the box.

Now for the suspension. The factory suspension plays a cruel trick on you. Just putting around on the trails, its great. But as soon as you roll onto the track like I occasionally like to do and rip it up for a few hours, brace yourself, because the front is softer than a kittens belly and valved for a fresh paved asphalt drag strip and the rear; it is wonderful until the last 6 in of travel and the shock and spring might as well be a steel I beam and you will feel your spine bunching up in your neck every time you land. So I went with a gt thunder XC rear linkage and 450r front shocks. The fronts are great but the springs are too stiff. With my weight I run the pre-load rings on the very top threads and its about right but they will still pick the front of the bike up about a inch. The linkage will lower the bike about a inch and you WILL need a stiffer spring. And take my advice, get the spring because it will allow the swing arm to travel right up into the bottom of the air box on landings and break the welds/plastic tabs (oem) on the box. I was still wanting more out of the suspension so I picked up a set of lonestar sport +2 arms and a axcalibar rear axle, she is right on time now! I love it everywhere. I will be getting some new springs and possibly a re-valve in the future and i’m sure it will be perfect then. Oh wait, what about the engine…..

Ran great but…….hot!!! I was running 97 in it and even with the added cooler oil temps were still holding around 200 flat out. I know this because im using a " CR’s only" oil dipstick thermometer. So I picked up the cooling fan from the fine fella on here and put it on. Dropped about 20 degrees off of it but I still felt it could do better. I was prepared for the fact I would possibly have to run cam 2 in it so I did. I slapped a 200 main jet in and filled her up with 110. Now…….160-175 all day in the dead heat trail riding, and runs like a raped ape. BTW, I use the run it like you stole it break in procedure and have never had a problem with any small engine, just my opinion. Start it, let it idle up to temp, then run the wheels off of it like you hate it for 5-6 passes at temp, Let it idle after for a few min till cools down a bit and shut it off and let it cool completely. Then repeat but this time after cooling completely, change the oil and filter and re-adjust you valves and your good to go. speaking on the valves. The ex’s are already super noisy up top to begin with and this cam makes it 1000 times worse but it runs great and hasn’t gotten worse so im guessing its the nature of the beast. I know now I need a standard front sprocket because it is just too much gear for the power . It could be faster, but for me and all the stock bolt on 400’s out there, bullet fast but no 450r by any means.

Outside of all that, completely happy with it. I just don’t think spending thousands of dollars making it just a tiny bit faster would have left me feeling the same way. In the woods, on the track, drag racing, putting around, don’t matter. Its just like it was from the factory but like a "stage 3" version. Its pretty forgiving everywhere and the first big ride I went on, burned through a whole tank in the first 3 hours there. That’s how much I liked it. I went easy on it for the rest of the three day trip and didn’t have one problem. All the pics (and more to come soon) are on my user page. She is till running strong and im super happy with it. Futer mods are as I said new springs and possible re-valve all the way round, bigger oil tank, and new plastics one day. :icon_ rocker:

Sorry for not doing this earlier but I still don’t have internet at the house yet and doing this on a phone would cause my thumbs to detach and run off. I wanted to do a writeup of a 440 ex build that would answer a lot of questions people have that are asked repeatedly, this will include some suspension questions as well. And since I’m not doing anything crazy or out of left field I thought this would be good to do. Sooooooo……..

Just like most, I love my 400 but……Im not a small guy (210) and it could use a little more pep than it had. It was all stock internals with bigger jets, HMF performance slip on, UM airbox, 13t front sprocket, with the UM air ducts and a wrapped header. The thing was; I was happy with it to be honest but the last few times I rode I noticed some blue puffs when letting the engine brake after a long hard WOT pull. Knowing the previous owner had never been into it I knew it was time. Its a 2001; think about that, 14 years old and now its getting its first top end. So I did some reading on the 440’s and decided to go that route. Not being made out of money, I went as cheap as I could without getting junk. Here is the list…………

-440 cylinder and piston (namura 11.1 to 1) – ebay 350$
-Stage 2 hotcam – ebay 125$
-Kibble white HD valve springs and titanium retainers – ebay – 100$
-Drivetrain performance HD clutch kit with cork friction pads – drivetrain performance 50$
-Used (barely, I knocked somebody on the head for this) hinson basket and new OEM hub – ebay 80$
-CR cam chain and new chain guides and tensioner OEM – motosport 175$
-Complete engine reseal kit – motosport 30$
-Curtis sparks ignition box – Curtis sparks 150$
-OEM crank bearings – motosport 35$
-GT thunder head studs – ebay 100$
-450r carb – ebay (knocked em in the head on this one too, it was new) 80 bones
– A pile of keihin assorted jet sizes for R carb – jets r us 50$

That’s it for the engine. Seriously…..After I pulled the engine and stripped the frame I went to town on the engine. I wanted to split it to see how everything looked before I went too spendy on cranks, bearings and all that. But real talk; there was nothing in there that showed extreme wear at all!!! The only things that were worn were a few teeth in the trans but very minimal wear. The clutch basket had been gone and I knew that before all this but just lived with a grabby clutch and stiff lever. I got new crank bearings only because the manual says to replace them, but they honestly didn’t need it. The crank was pristine, I really don’t think the last owner ever really ran for more than a day or two since 01. First I went to work on the head, checked everything over, hand lapped valves, installed the HD valve springs, cleaned her up real good and done. Resealed the motor, crank bearings in, put the halves together, and started on the cylinder (the old liner was my blue smoke, she was gone!). The stud kit can be done at home but you MUST use a drill press and you MUST do EXACTLY as the instructions say or you will mess up a brand new jug. Its not bad and anybody with some good mechanical knowledge can get it done easily on their own. Assembled the piston and cylinder on the bike (they fit fine together, saw a lot of horror stories of namura pistons and "ebay" kits but I have always had good luck with them) and on went the head. Installed the cam and rocker box, cam chain and clutch, and all the covers. I run rotella T 15-40 in it and just about everything I own with a small engine, mobil delvac 3000 will do too (cat DEO 15-40).

I sent the frame off to be powder coated and once it came back, everything went back on. I replaced a bunch of hardware that was rusted and stripped out or seized, replaced the dreaded swing arm bolt (which kicked my A**!!! getting it out) and replaced almost all the connectors on the bike with deutch DT connectors. I never trust those dinky bullet connectors and hate the PITA factory connectors. I installed a second oil cooler as the weather here in southern VA in the summer stays between 90 and 100 for the most part and I do a lot of woods/trail riding so I knew cooling this pig would be crucial. I used rubber fuel line and screw clamps to tie in to the factory cooler lines for the second cooler. Its a 12×8 (I think) aluminum pro-cool unit from auto zone, it will take you for about 40 bucks and comes with the hose and clamps you need already in the box.

Now for the suspension. The factory suspension plays a cruel trick on you. Just putting around on the trails, its great. But as soon as you roll onto the track like I occasionally like to do and rip it up for a few hours, brace yourself, because the front is softer than a kittens belly and valved for a fresh paved asphalt drag strip and the rear; it is wonderful until the last 6 in of travel and the shock and spring might as well be a steel I beam and you will feel your spine bunching up in your neck every time you land. So I went with a gt thunder XC rear linkage and 450r front shocks. The fronts are great but the springs are too stiff. With my weight I run the pre-load rings on the very top threads and its about right but they will still pick the front of the bike up about a inch. The linkage will lower the bike about a inch and you WILL need a stiffer spring. And take my advice, get the spring because it will allow the swing arm to travel right up into the bottom of the air box on landings and break the welds/plastic tabs (oem) on the box. I was still wanting more out of the suspension so I picked up a set of lonestar sport +2 arms and a axcalibar rear axle, she is right on time now! I love it everywhere. I will be getting some new springs and possibly a re-valve in the future and i’m sure it will be perfect then. Oh wait, what about the engine…..

Ran great but…….hot!!! I was running 97 in it and even with the added cooler oil temps were still holding around 200 flat out. I know this because im using a " CR’s only" oil dipstick thermometer. So I picked up the cooling fan from the fine fella on here and put it on. Dropped about 20 degrees off of it but I still felt it could do better. I was prepared for the fact I would possibly have to run cam 2 in it so I did. I slapped a 200 main jet in and filled her up with 110. Now…….160-175 all day in the dead heat trail riding, and runs like a raped ape. BTW, I use the run it like you stole it break in procedure and have never had a problem with any small engine, just my opinion. Start it, let it idle up to temp, then run the wheels off of it like you hate it for 5-6 passes at temp, Let it idle after for a few min till cools down a bit and shut it off and let it cool completely. Then repeat but this time after cooling completely, change the oil and filter and re-adjust you valves and your good to go. speaking on the valves. The ex’s are already super noisy up top to begin with and this cam makes it 1000 times worse but it runs great and hasn’t gotten worse so im guessing its the nature of the beast. I know now I need a standard front sprocket because it is just too much gear for the power . It could be faster, but for me and all the stock bolt on 400’s out there, bullet fast but no 450r by any means.

Outside of all that, completely happy with it. I just don’t think spending thousands of dollars making it just a tiny bit faster would have left me feeling the same way. In the woods, on the track, drag racing, putting around, don’t matter. Its just like it was from the factory but like a "stage 3" version. Its pretty forgiving everywhere and the first big ride I went on, burned through a whole tank in the first 3 hours there. That’s how much I liked it. I went easy on it for the rest of the three day trip and didn’t have one problem. All the pics (and more to come soon) are on my user page. She is till running strong and im super happy with it. Futer mods are as I said new springs and possible re-valve all the way round, bigger oil tank, and new plastics one day. :icon_ rocker: