Honda 400ex vs kfx400

[YamahaJS93]

thinking about picking one up recently,used, and just curious which engines are stronger durability wise. i know the ex is tough as nails and im leaning towards that for trails, but the kfx400 is water cooled but thats just another thing to keep an eye on, so which would be the best? thanks, and valves? will the ex be a better choice for adjustments?

[leafsrule16]

KFX is faster, liquid cooled, has better suspension and all models have reverse. As far as maintance a 400ex is a little less maintance, you can get away without checking the valves for a bit longer and stuff but don't let that scare you, in my opinion a kfx/dvx/z400 are the better, more fun bike.

[rdlsz24]

If you're concerned about valve adjustments the 400ex is the older style with the access caps and you adjust the rockers. No math involved.

The KFX is a newer machine with the buckets and shims, and the head cover has to come off. For whatever it's worth I owned my 03 KFX for 8 years and never opened the engine up, even to adjust the valves.

I only sold it last summer to upgrade to an 08 KFX 450R. Many of my riding buddies were getting 450s and I didn't like being left in the dust.

Rob

Edited April 24, 2013 by 03YZ85

[Yfzrider2007]

KFX is faster, liquid cooled, has better suspension and all models have reverse. As far as maintance a 400ex is a little less maintance, you can get away without checking the valves for a bit longer and stuff but don't let that scare you, in my opinion a kfx/dvx/z400 are the better, more fun bike.

had my 400ex since 2007 my little brothers quad actually oil probably gets changed once every 5 months lmfao.... never valve checked on it. man that thing still runs like when we picked it up last for freaking ever.. one time he ran it dry on oil. things been through hell and still runs perfect

[C.R.R.BRAAAPER]

400ex's are junk! i along with a few of my friends all had them. All junk, if you ride them to hard for to long they over heat. The rings wear pretty quick so they are going to smoke after like 10 hours off of a rebuild. I had an 01 and the older i got the more i disliked the bike. Air cooled, suspension sucked, my motor was constatnly being worked on because it chewed through cams and timing chains. I love hondas... but the 400ex is in need of an update.

[0macman0]

The XR engine is almost identical to the EX engine, my XR is a 96', all original and doesn't smoke. If it was overheating, either it was running lean, or you were going too slow. Chewed up cams? Sounds like it overheated ALOT, or the oil wasn't getting changed near enough. These air cooled engines rely on fresh high quality oil to keep themselves cool, as well as constant airflow.

[C.R.R.BRAAAPER]

I changed the oil after every 4 hours. Ran 20-50 and slow is not my thing lol. I had it race ready. Had it bored to a 416 stage 2 hot cam the whole works. now i have a cr250.

[leafsrule16]

400ex's are junk! i along with a few of my friends all had them. All junk, if you ride them to hard for to long they over heat. The rings wear pretty quick so they are going to smoke after like 10 hours off of a rebuild. I had an 01 and the older i got the more i disliked the bike. Air cooled, suspension sucked, my motor was constatnly being worked on because it chewed through cams and timing chains. I love hondas... but the 400ex is in need of an update.

Sounds like you just had a worn out peice of crap. That happens, 400ex's seem to get picked up by kids who don't look after them. Also, a 416ex is far from "race ready", that may have been a primary source of your problems there. If you ride anything "hard" for long it's going to overheat, ride the guts out of a liquid cooled new 450 off the limiter for a long time like most of you quad guys seem to do and it's going to overheat. Try riding a 4 stroke dirtbike in the woods, same thing, they overheat. Air cooling isn't significantly worse then liquid cooling as far as cooling capasity goes.

Edited April 24, 2013 by leafsrule16

[C.R.R.BRAAAPER]

I bought it stock... 416ex: 11:1 wiseco, stage 2 cam port and polished hot rod crank, custom air box, k&n filter, dyno jets, replaced stator, big gun ignitiom/cdi, pmr coil, renthal twin wall bars, motion pro twist throttle, asv brake/clutch levers, hetrick racing full exhaust, moose bark buster hand gaurds, plus 2 steering stem, ohlins dampner, elka plus 2 a arms elka shocks, plus 1 swing arm, plus 3 durablue axel, ac bumper and nerfs, douglas lock wheels maier race cut plastics. I know what im talking about. Been there done that. I think they are junk and wouldn't recomend them to anyone until they are updated to todays standards. They are very low tech.

[Yfzrider2007]

I changed the oil after every 4 hours. Ran 20-50 and slow is not my thing lol. I had it race ready. Had it bored to a 416 stage 2 hot cam the whole works. now i have a cr250.

they say directly on rockymountain on the high comp piston description makes it run hot... stock except a pipe and jet kit and all that nothing will go wrong mine never smokes NEVER and i bet we have close to everybit of 300-400 hours still runs crisp

[Yfzrider2007]

I bought it stock... 416ex: 11:1 wiseco, stage 2 cam port and polished hot rod crank, custom air box, k&n filter, dyno jets, replaced stator, big gun ignitiom/cdi, pmr coil, renthal twin wall bars, motion pro twist throttle, asv brake/clutch levers, hetrick racing full exhaust, moose bark buster hand gaurds, plus 2 steering stem, ohlins dampner, elka plus 2 a arms elka shocks, plus 1 swing arm, plus 3 durablue axel, ac bumper and nerfs, douglas lock wheels maier race cut plastics. I know what im talking about. Been there done that. I think they are junk and wouldn't recomend them to anyone until they are updated to todays standards. They are very low tech.

thats why you dont try making a trail quad into a race quad. yes there low tech but i would reccomend to any beginner you cant kill them

[Yfzrider2007]

Sounds like you just had a worn out peice of crap. That happens, 400ex's seem to get picked up by kids who don't look after them. Also, a 416ex is far from "race ready", that may have been a primary source of your problems there. If you ride anything "hard" for long it's going to overheat, ride the guts out of a liquid cooled new 450 off the limiter for a long time like most of you quad guys seem to do and it's going to overheat. Try riding a 4 stroke dirtbike in the woods, same thing, they overheat. Air cooling isn't significantly worse then liquid cooling as far as cooling capasity goes.

i have a 450 but it doesnt have a rev limiter... if it does i havent found it yet ?

[leafsrule16]

I bought it stock... 416ex: 11:1 wiseco, stage 2 cam port and polished hot rod crank, custom air box, k&n filter, dyno jets, replaced stator, big gun ignitiom/cdi, pmr coil, renthal twin wall bars, motion pro twist throttle, asv brake/clutch levers, hetrick racing full exhaust, moose bark buster hand gaurds, plus 2 steering stem, ohlins dampner, elka plus 2 a arms elka shocks, plus 1 swing arm, plus 3 durablue axel, ac bumper and nerfs, douglas lock wheels maier race cut plastics. I know what im talking about. Been there done that. I think they are junk and wouldn't recomend them to anyone until they are updated to todays standards. They are very low tech.

That's why yours is junk, because too much is done to it. In stock form they are a bit mild but are rock solid and tough as nails. I too tried to turn my 400 (mine was a KFX) into a race bike with the same results as you got, if you want a race bike buy one and stop bashing 400 ex's.

[2004greenkx250f]

400ex's are junk! i along with a few of my friends all had them. All junk, if you ride them to hard for to long they over heat. The rings wear pretty quick so they are going to smoke after like 10 hours off of a rebuild. I had an 01 and the older i got the more i disliked the bike. Air cooled, suspension sucked, my motor was constatnly being worked on because it chewed through cams and timing chains. I love hondas... but the 400ex is in need of an update.

Far from it, you just got a bad, abused atv. My friend has put his 00 through hell and back and it is still kicking. Mine's been on some rough rides as well, wouldn't have it any other way.

[Yfzrider2007]

That's why yours is junk, because too much is done to it. In stock form they are a bit mild but are rock solid and tough as nails. I too tried to turn my 400 (mine was a KFX) into a race bike with the same results as you got, if you want a race bike buy one and stop bashing 400 ex's.

exactly what i said man!! no trail bike is ment to be turned into a nascar lol.. get a 450 or 525

[C.R.R.BRAAAPER]

Then I just had crap luck with mine. But I can garentee I wouldn't ever get another one. Id just get 450r or a ktm 505.

[Goodys_Atv]

I bought it stock... 416ex: 11:1 wiseco, stage 2 cam port and polished hot rod crank, custom air box, k&n filter, dyno jets, replaced stator, big gun ignitiom/cdi, pmr coil, renthal twin wall bars, motion pro twist throttle, asv brake/clutch levers, hetrick racing full exhaust, moose bark buster hand gaurds, plus 2 steering stem, ohlins dampner, elka plus 2 a arms elka shocks, plus 1 swing arm, plus 3 durablue axel, ac bumper and nerfs, douglas lock wheels maier race cut plastics. I know what im talking about. Been there done that. I think they are junk and wouldn't recomend them to anyone until they are updated to todays standards. They are very low tech.

What did you run for fuel. My quads well built and its been nothing but good

[C.R.R.BRAAAPER]

What did you run for fuel. My quads well built and its been nothing but good

I run 93 pump gas in everything

[Yfzrider2007]

I run 93 pump gas in everything

did it say run higher octane fuel?

[C.R.R.BRAAAPER]

did it say run higher octane fuel?

its recommended to run 93 in them stock. And yes it had an 11:1 piston