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400 ex questions


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hey guys my dad has a 400 ex and im sick of having to wait for him when we ride so i told him if he gives me a 1500 budget i would make his bike nice (although i dont think its really worth it to soup up a 400 ex) so this is what i was thinking a 440 big bore kit, cams, 8 paddle haulers thats i got so far what do you think is the best mods for it. also im deciding between the 416 bore kit and the 440 bore kit ive heard that the 416 has more power any opinons or help would be greatly appriciated

 

thanks for any help sorry its not a shee question

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Sparks builds the fastest 426ex I've ever seen...he hung up on me when I asked about custom exhaust for my hybrid though... A 426ex built right will give a 450 a run for it's money.... much over that and you lose alot of reliability... A big bore kit won't run worth shit untill you get it ported though... it's all in the porting....

 

 

 

Mike

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me and my dad put his thru the 440 treatment and got 40.4 horse on the dyno. all it has is a wiseco 440 kit, stage one hotcam, porting, yoshi full exhuast and a keihin 39mm fcr carb. not bad for a home port-job. in the next couple of weeks mine goin down for a 426 that we are gonna build a little hotter, hopefully ill be puttin out about 42 once we get the carb and a better cam in it.

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My brother has the stage 2 hotcam, full hmf exhaust, and k&n filter w/ lid off. It will run with a piped banshee untill the shee clicks into 4th and it slowly walks away then 6th will destroy it...

 

All of those mods and the 8 paddle haulers will run you about $1000 just off the top of my head. And you dont needle heavy duty valve springs if you only do a cam and pipe.

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I recently bought a 440ex from a friend for cheap.I must say it is a lot of fun in the trails(sand)!

I was suprised how much tourqe it has.However no way will it hang with the shee,but its not near the workout to ride.I'm probly just gettin old though. :cry:

The bad side to this bike is it has a history of blowing head gaskets(twice in the last 2 years).I've read up a little & this seems to be a pattern with the 440 kits.I'd like to hear about some peoples 440s holding up well.Would make me feel better! I would like to see what it would do with porting& bigger valves.

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I recently bought a 440ex from a friend for cheap.I must say it is a lot of fun in the trails(sand)!

I was suprised how much tourqe it has.However no way will it hang with the shee,but its not near the workout to ride.I'm probly just gettin old though.  :cry: 

The bad side to this bike is it has a history of blowing head gaskets(twice in the last 2 years).I've read up a little & this seems to be a pattern with the 440 kits.I'd like to hear about some peoples 440s holding up well.Would make me feel better! I would like to see what it would do with porting& bigger valves.

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Call sparks and get a head gasket from them and start running 110 and your head gasket problems will go away. I went thru that on mine. I just put a wiseco 440 kit with the 11-1 piston. Had the head ported shortend valve guides and the biggest cam web cam has. Pumped fuel in it thru a 41 fcr carb. A buddy has it now and he only weighs about 150 lbs. He gives guys fits down at the dunes. You have to figure porting is probably going to be around 400 maybe more maybe less. Hardend rockers which on the 400ex is a must and I think I paid a couple hundred for those. FCR carb was around 550. That's around 1200 or so and that doesn't include the sleeve and piston or having it done or the cam and valve guides. In the long run you would be better off buying a banshee or a yfz.

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I was working on an ex today and those things SUCK maintnance wise could hardly get the carb bowls offor fit a wrench any were ne ways i have a prob and i think its the jetting it bogs at 1/2 thrott. i tried leanin out because exhuast was dark it had a 248 main looked a little clogged cleaned it and still doin the same any help would be great i m at sea level - 500ft THANKS

Edited by FasterThanU90
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I was working on an ex today and those things SUCK maintnance wise could hardly get the carb bowls offor fit a wrench any were ne ways i have a prob and i think its the jetting it bogs at 1/2 thrott. i tried leanin out because exhuast was dark it had a 248 main looked a little clogged cleaned it and still doin the same any help would be great i m at sea level - 500ft  THANKS

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a 248 main is WAY to big for an EX, go down to about a 165 and it should work alot better.

 

the 400ex may not keep up with a banshee on top speed but not alot of people are balls out top gear the whole time they ride. at the dunes im alomost always in 3rd in the trails and fourth on the open sand, i have a 16 tooth from sproket in it and it doesnt want to pull fifth very well.

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a 248 main is WAY to big for an EX, go down to about a 165 and it should work alot better.

 

the 400ex may not keep up with a banshee on top speed but not alot of people are balls out top gear the whole time they ride. at the dunes im alomost always in 3rd in the trails and fourth on the open sand, i have a 16 tooth from sproket in it and it doesnt want to pull fifth very well.

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Im running a 165 main and it seems to be just fine on top, the bottom end won't idle very well and we were contemplating going to a 42 pilot? This is just with a full exhaust, stage 2 cam, hi comp piston (.020" over), uni filter, and a rev box.

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