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i'd probably do it i love the way my 400ex rode/handled alot different than my r does now
 

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Hey just wanted to know if the 450r motor will fit in a 400ex frame.
If so what kinda changes has to be made to the 400ex[/b]
I did it! It's a beeeoootch!.....Don't do it!
I did a crf450 in my 400ex. Pretty much the same deal.
Check it out.....
[/b]

what kind of problems did you run into??
[/b]
Where do I start?...LOL...None of the engine bracket are useable. You have to make your own. The swingarm pivot bolt is too small in O.D., you have to make a bushing for it. The drive sprocket will not line up with the rear sprocket, you have to have the inside fo the left pivot mount on the swingarm milled down approx 3/16". Then shorten one pivot spacer & make a new (longer) one for the other side. The countershaft sprocket in too low to clear the swinarm rub pad, so you have to run a large countershaft sprocket so the chain will not eat a whole in the swinarm. That gears the bike even higher. The trans in the 450 is already geared to high for an atv application. So you need to have a custom rear sprocket made. I think it was 50 tooth or maybe a bit larger. You have to make or remake a headpipe & silenser, the silencer brackets or all wrong. You need to put a overflow bottle somewhere & radiator, mounts for the radiator. Hoses are pain. The crf waterpump cover directs the hose to high & a different style is needed. The kick starter will hit the frame. You need a shaft extention & shorter kicker, it hits the fender when you kick it. The carb is the worst! When the motor is set to line up with the rear sprocket & positioned to clear the gas tank, the crf carb is about 1" from the cross-tube on the frame. No way to rout a intake tube. I mean no way!. We had to cut the cross-tube & subframe cross-tube, weld in a pc. of thick wall 2.5" pipe. Then had to strengthin that, hard to explain.
Then we ran a large radiator type hose through the pipe & on to the filter. I am sure I am forgetting a bunch. After it's done, the 400ex handles like crap. I mean compared to a 450r. The only reason we did it, was because honda did not have a high perf. 450 quad. As soon as we found out honda was coming out the 450 in 2004. I listed mine on ebay, before they hit the market. Now the 04 stock 450 did not run quite as good, w/ less compression & non-fcr carb. The trx450r was a much better handling bike! Also easy to make it as fast or faster. I could not emagine doing the swap with out having the complete crf450 bike to rob parts from. Carb, elect, hoses, brackets, bolts, etc. If it was me, & had a 400ex & crf450 engine. No question about it, I would sell both & pick-up a nice used trx450r. They are all over the place, good deals out there. It was fun, but pain in the butt!...LOL...I guess a guy could mickey mouse the piss out of the project, but it would be worthless to ever get any money out of when your done with it. The frame will never go back to a 400ex. To many modification. You should have seen all the 400ex raptor 660 guys back in 2003! We would roll up to the dune drag hill, position your legs as to hide the engine! We would let them go & pass them in a wheelie!...LOL...Guys would come over to see what the hell? They looked so factory done, they all thought we worked for honda & where testing prototype 450's...LOL.
That was such a big rummor back then????? Will or wont honda come out with a 450 quad?
 

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QUOTE(dhamr @ Apr 6 2009, 07:01 PM) index.php?act=findpost&pid=671108
<div class='quotemain'>Hey just wanted to know if the 450r motor will fit in a 400ex frame.
If so what kinda changes has to be made to the 400ex[/b]
I did it! It's a beeeoootch!.....Don't do it!
I did a crf450 in my 400ex. Pretty much the same deal.
Check it out.....
[/b]

what kind of problems did you run into??
[/b][/quote]

Where do I start?...LOL...None of the engine bracket are useable. You have to make your own. The swingarm pivot bolt is too small in O.D., you have to make a bushing for it. The drive sprocket will not line up with the rear sprocket, you have to have the inside fo the left pivot mount on the swingarm milled down approx 3/16". Then shorten one pivot spacer & make a new (longer) one for the other side. The countershaft sprocket in too low to clear the swinarm rub pad, so you have to run a large countershaft sprocket so the chain will not eat a whole in the swinarm. That gears the bike even higher. The trans in the 450 is already geared to high for an atv application. So you need to have a custom rear sprocket made. I think it was 50 tooth or maybe a bit larger. You have to make or remake a headpipe & silenser, the silencer brackets or all wrong. You need to put a overflow bottle somewhere & radiator, mounts for the radiator. Hoses are pain. The crf waterpump cover directs the hose to high & a different style is needed. The kick starter will hit the frame. You need a shaft extention & shorter kicker, it hits the fender when you kick it. The carb is the worst! When the motor is set to line up with the rear sprocket & positioned to clear the gas tank, the crf carb is about 1" from the cross-tube on the frame. No way to rout a intake tube. I mean no way!. We had to cut the cross-tube & subframe cross-tube, weld in a pc. of thick wall 2.5" pipe. Then had to strengthin that, hard to explain.
Then we ran a large radiator type hose through the pipe & on to the filter. I am sure I am forgetting a bunch. After it's done, the 400ex handles like crap. I mean compared to a 450r. The only reason we did it, was because honda did not have a high perf. 450 quad. As soon as we found out honda was coming out the 450 in 2004. I listed mine on ebay, before they hit the market. Now the 04 stock 450 did not run quite as good, w/ less compression & non-fcr carb. The trx450r was a much better handling bike! Also easy to make it as fast or faster. I could not emagine doing the swap with out having the complete crf450 bike to rob parts from. Carb, elect, hoses, brackets, bolts, etc. If it was me, & had a 400ex & crf450 engine. No question about it, I would sell both & pick-up a nice used trx450r. They are all over the place, good deals out there. It was fun, but pain in the butt!...LOL...I guess a guy could mickey mouse the piss out of the project, but it would be worthless to ever get any money out of when your done with it. The frame will never go back to a 400ex. To many modification. You should have seen all the 400ex raptor 660 guys back in 2003! We would roll up to the dune drag hill, position your legs as to hide the engine! We would let them go & pass them in a wheelie!...LOL...Guys would come over to see what the hell? They looked so factory done, they all thought we worked for honda & where testing prototype 450's...LOL.
That was such a big rummor back then????? Will or wont honda come out with a 450 quad?
[/b][/quote]
Damn! What did all that cost you in the end?
 

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Well, the 400ex where new, & the crf450 was new, after we parted out what we did not need from the 400 & 450 & bought the new parts we needed, sprockets, radiator, chain, kick starter, extention, etc. Seems as if it was the better part of 8k? I think I sold the new 400ex engine for 1600? That was when parts where selling good, & it was all new parts. Got good money for the 450 forks & frame...etc. Not bad when you consider new 400ex were about 6300 out the door then. Thats no labor also, because we did all our own fab. work. My buddy is really good at that kinda stuff.
 

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It is weird to me that it would be that difficult. "Back in the day..." there were ex's all over the place with either 450r bike motors or even yz motors in them. You used to see them at MX races all the time. Then the YFZ came out and pretty much overnight all the hybrid quads started to disapear. Surely places like Lone Star etc. had kits to do most of it. Not that any of it is still around.
 

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It is weird to me that it would be that difficult. "Back in the day..." there were ex's all over the place with either 450r bike motors or even yz motors in them. You used to see them at MX races all the time. Then the YFZ came out and pretty much overnight all the hybrid quads started to disapear. Surely places like Lone Star etc. had kits to do most of it. Not that any of it is still around.[/b]
I never seen to many 400ex hybreds but back then all you saw was 250r aftermarket frames with yz or crf motors. I am pretty sure you could buy a aftermarket frame and the parts to bolt the motor right up. That is an awesome 400ex no way I could hack up a brand new 400ex and crf450! That takes some guts lol
 

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If you are that interested, I have a 400ex frame that I modded to do a "drop in" hybrid with a CRF 450. I was looking for a CRF and the TRX came out. Now here I sit with a frame ready to go.

PM me if you're interested, I'll let it go dirt cheap.
 

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It is weird to me that it would be that difficult. "Back in the day..." there were ex's all over the place with either 450r bike motors or even yz motors in them. You used to see them at MX races all the time. Then the YFZ came out and pretty much overnight all the hybrid quads started to disapear. Surely places like Lone Star etc. had kits to do most of it. Not that any of it is still around.[/b]
I never seen to many 400ex hybreds but back then all you saw was 250r aftermarket frames with yz or crf motors. I am pretty sure you could buy a aftermarket frame and the parts to bolt the motor right up. That is an awesome 400ex no way I could hack up a brand new 400ex and crf450! That takes some guts lol
[/b]
You correct. The aftermarket frame where set up for the crf motor. I never seen any of racers use a stock 400ex frame. There was a kit though. It was for a aftermarket 400ex frame to put a crf engine in it. We bought 2 of them. Thats where we got the short kicker, shaft extention, pivot bushing & engine brackets. The brackets where a joke! We had to make our own. Did help having them as a pattern. The bushing was cool. Thats what I meant by you need to make most of it, because those kits are long gone. Back to the point of.....DON'T DO IT!!!!.....Waste of money & time. When are done, all you got is a abortion on your hands....LOL....I dumped mine while guys still had those hybrid bikes. The guy who bought mine had one & was going to use mine for a practis bike?....
 

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I did the swap on my 07 400ex and all i can say is this. If you race mx, just buy the 450r. If you plan on xc and you can do it cheap, i like my 400ex. I dont think that the 400ex jumps as well but id much rather have it in the woods. Ill still keep it when i buy my new 450r when honda decides to go fuel injection.
 

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i did it and it was easy i used a 07 450er motor in a 02 frame once you get the swing arm bolt in just make sure the tank dont sit on the motor move it up and down until you find that sweet spot and make some mounts to fit but i did move the lower frame mounts back about a inch give or take
 

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I did it! It's a beeeoootch!.....Don't do it!
I did a crf450 in my 400ex. Pretty much the same deal.
Check it out.....
I did it! It's a beeeoootch!.....Don't do it!
I did a crf450 in my 400ex. Pretty much the same deal.
Check it out.....
what kick starter did you have to use im am doing the swap now need to figure the kicker and the header out because the head is diffrent then the trx450r
 

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06 HRC cam new piston rings crank shaft cam chain sparks full exhaust uni filter many more bolt ons!
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what kick starter did you have to use im am doing the swap now need to figure the kicker and the header out because the head is diffrent then the trx450r
Wicked cool swap, and he did it years ago. Did you finish your swap yet? If so send some pics. The COMMUNITY would love to see it. Put some stage 3 or up elka,s on there, there are good shocks despite what some might say. My two favorite quads joined together in matrimony. 😂
 
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