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View Full Version : 350x vs. 400ex


2 QuicK
11-14-2002, 08:37 PM
Which one's faster all around?? Asumming both are stock. Any one know the hp numbers for the 350x? Thanx.
330exracer122
11-14-2002, 09:11 PM
400 will be spanked :(
CBW
11-14-2002, 10:16 PM
350X,,,,,,,i tried my 400 when it was new and stock against my stock 350X.........the 400 lost.
ZMAN
11-15-2002, 11:35 AM
is the 350x a 4 or 2 stroke?
CBW
11-15-2002, 01:14 PM
Originally posted by ZMAN
is the 350x a 4 or 2 stroke?

4 stroke, 6 speed manual, 4 valve.
maxximus
11-15-2002, 02:33 PM
As a 350x owner again...(sold mine 7 yrs ago, but now bought another and havin fun)

They have 28 hp all stock. and weigh 320 lbs.

I believe the 400ex is 23-25.

goin old school again!!:D
Bean
11-15-2002, 03:51 PM
the youngest 350 i THINK had 6 gears, so if i still had a 400, i would want a 350 bored up to a 440 or something, 416 mabe, it will fly
86atc250r
11-15-2002, 03:54 PM
OK guys... Have any of you compared the innerds of the two engines?

Here it goes.

ATC350X with a slightly better than stock pipe lays down approx 22hp

TRX400EX on the same dyno outputs 27hp - bone stock with a correctly adjusted throttle.

If you ever get a chance, take a look at the two cylinder heads and the two carburetors. The 400EX head outflows the 350X by a good margin, ports are a lot larger and chamber is of better design. The stock 400EX carburetor has a larger slide as well as a larger in and outlet.

The 350X engine has a little more compression, an extra gear, and the ATC has less weight.

When I've raced the two the 400EX won, no contest.

Bear in mind we've currently got two 350X's (85 and 86), owned about 5 of them at one time or another, and still have one 86 ATC250R. Even as much as I hate to admit it, the piped ATC250R had trouble taking on the 400EX until the very top which surprised the heck out of me.

I personally think the stories of people outrunning a 400EX with a 350X stem from a race with a 400EX that didn't have it's throttle cable adjusted properly. When we raced our two, the 400EX's cable was adjusted properly.

As far as power curve goes - the 350X had a hint more bottom than a 400EX but that's about as far as it goes, after that the EX engine significantly outperforms it.

If the 350X engine truly was of better design and outperformed a 400EX engine you'd see conversions - how many 400EX to 350X engine conversions have you ever seen?
Ex_Rider43
11-15-2002, 04:21 PM
good point 86atc250r...

I beleive the 350x will lost .my friend has won against it at the drags this summer and his 400 is stock.
oregonrider89
11-15-2002, 04:38 PM
Top speed the 350X is faster, which is to be expeced with 6 gears. But acceleration I think the 400ex is quicker.

oregonrider89
CBW
11-15-2002, 08:48 PM
Originally posted by Bean
the youngest 350 i THINK had 6 gears


the 85 and 86 350X's both had 6 gears............
racerx573
11-15-2002, 10:31 PM
Ive seen a lotta 250R to 350X conversions. I guy a know has 426X in a full Laeger's chassis. He dominated the 4-stroke class in District 5. He beat em all, even this guy w/ a 500EX, a few dales, and some guys with 450F's in EX frames. THE DUDE IS FAST! and so is his bike. HOLESHOT HOLESHOT HOLESHOT
joeroadking
11-16-2002, 02:40 PM
I built 2 250x with 350x motors, and also have a 400ex, my brother rides the 350 x the 350 x makes more low end power but in a flat out race 400ex is faster top end assuming you are on level ground.
OutlawEX
11-16-2002, 03:55 PM
my buddy threw a 350X motor in his 250R chassis and my 400 was ported ,am everyhting and his is 432 powroll bigbbore,stroker,ported and his and mine are competeible
maxximus
11-18-2002, 01:56 PM
The REAL HP on the 350x is 28...

Whomever thinks it is 22 needs to review the repair manual on the 350x. Just wanted to clear this up!!

My cr500 will eat them both!!
11-18-2002, 02:06 PM
Originally posted by maxximus


My cr500 will eat them both!!

Ummmmm,,,ya think..:huh :confused: :rolleyes:
86atc250r
11-18-2002, 03:38 PM
Whomever thinks it is 22 needs to review the repair manual on the 350x. Just wanted to clear this up!!

The numbers I quoted didn't come from a manual, they are actual rear wheel numbers from a chassis dyno of a respected race engine builder.

The 28 you are quoting from a manual is the SAE number on the title. If memory serves me correctly this number is approx 33hp on a 400EX.
BKVIEW4U
11-18-2002, 07:06 PM
i raced a 350x in the sand about 12 times . he beat me once when i stood it up too far and had to back out. i have a 16tooth front sprocket and i would pull on him bad from 3rd gear on and stay there . he had the same mods i had except he said he had stock gearing . and he was about 100 pounds lighter than me . not including the difference in weight of the 2 bikes