Howcome the YFZ450 is much faster than the 400ex? - Yamaha ATV Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 32 Old 12-24-2004, 05:08 PM Thread Starter
Senior Member
 
Join Date: Jul 2003
Posts: 315
Howcome the YFZ450 is much faster than the 400ex?

I was thinking why the 450 is much faster than the honda 400 ex.
It`s just a few cc`s more and a litlle bit lighter.

Ride it like you stole it
tudo808 is offline  
Sponsored Links
Advertisement
 
post #2 of 32 Old 12-24-2004, 06:08 PM
Senior Member
 
Join Date: Aug 2003
Location: Northern Cali
Posts: 338
Send a message via AIM to The J Send a message via MSN to The J
Lets see here: Why is the YFZ is faster than the 400ex?
1. The 400ex was designed how long ago?
2. YFZ has DOHC, EX has SOHC
3. The YFZ has extra 39cc
4. If I remember correctly the YFZ has a thinner piston skirt and a lighter piston all together.
5. Fourstroke technology has really increased in the time since the 400ex was released.
6. It's a Yamaha. Just Kidding

Over the past few years with the motorcycle and ATV industry steering away from two-strokes more R&D has been put into four-strokes allowing for larger numbers out of similar displacement engines. My uninformed $0.02 worth.


J

YFZ 450
The J is offline  
post #3 of 32 Old 12-24-2004, 06:31 PM
Senior Member
 
Join Date: Jun 2004
Location: Oakboro, NC
Posts: 2,833
Send a message via AIM to Foxracin
Quote:
Originally Posted by The J
Lets see here: Why is the YFZ is faster than the 400ex?
1. The 400ex was designed how long ago?
2. YFZ has DOHC, EX has SOHC
3. The YFZ has extra 39cc
4. If I remember correctly the YFZ has a thinner piston skirt and a lighter piston all together.
5. Fourstroke technology has really increased in the time since the 400ex was released.
6. It's a Yamaha. Just Kidding

Over the past few years with the motorcycle and ATV industry steering away from two-strokes more R&D has been put into four-strokes allowing for larger numbers out of similar displacement engines. My uninformed $0.02 worth.


J
Pretty much sums it up right there.

02 XC Raptor


AtvNC.com
Foxracin is offline  
Sponsored Links
Advertisement
 
post #4 of 32 Old 12-24-2004, 06:35 PM
Senior Member
 
Join Date: Apr 2004
Location: michigan
Posts: 287
Send a message via AIM to creechfan
you prety much summed it up!


....allso the YFZ motor revs higher, fasterer and harder because of the reasons above....makin' it move past the HAHAhonda JKJK....honda makes a great bike....
creechfan is offline  
post #5 of 32 Old 12-24-2004, 06:58 PM
Crowd Control
 
Warrior's Avatar
 
Join Date: Oct 2001
Location: Oklahoma.
Posts: 4,336
Send a message via AIM to Warrior Send a message via MSN to Warrior Send a message via Yahoo to Warrior
Isnt the 400 still just air/oil cooled?

Cruz/Warrior
'93 Banshee, Passion, FAST, Cascade, Noss, CP Ind, JJ&A, DMR, Skat Trak, LSR
'88 350r, CT, LSR, ESR, Quad Tech, Skat Trak, TCS, Works, Maier, HiPer
'04 CR250r
'09 YFZ450r
, Stolen
'09 KTM 505 SX
Warrior is offline  
post #6 of 32 Old 12-24-2004, 07:03 PM
Senior Member
 
Join Date: Jan 2003
Location: Michigan
Posts: 6,520
Send a message via AIM to NitrousGuy
the fact that one is a sohc sesign, and the other is a dohc has nothing to do with being faster.


if anything, the dohc design has more of a paracitic loss because of the extra friction of the added camshaft .

The Original Michrider
( "Michriders", Coined by R4Race)
Tug Hill Veteran '03, '04

"The Lord Helps Me, So I Will Not Be Ashamed. I Will Be Determined. And I Know I Will Not Be Disgraced" ~ Isaiah 50:7

" And What We Have Is Much More Than They Can See" ~ DeLaSoul
NitrousGuy is offline  
post #7 of 32 Old 12-24-2004, 07:33 PM
Senior Member
 
Join Date: Jan 2004
Location: Phenix City, AL
Posts: 285
Send a message via AIM to elliptic
Quote:
Originally Posted by NitrousGuy
the fact that one is a sohc sesign, and the other is a dohc has nothing to do with being faster.


if anything, the dohc design has more of a paracitic loss because of the extra friction of the added camshaft .
I dont know about that, isnt the 450r also sohc and I do believe its slower j/p

'04 YFZ 450 Red/White.
'03 KFX 400 Green.
elliptic is offline  
post #8 of 32 Old 12-24-2004, 10:25 PM
Senior Member
 
Join Date: Jun 2003
Location: jackson, mi
Posts: 525
yea the sohc dohc thing doesn't matter much. But the overall state of tune on the 400ex motor, which was taken from the xr400, which was taken from the xr350, is old. The xr350 came out in like 83 or something. The 400ex is a trail machine and the yfz is a race machine. the air vs water cooling thing is a factor although not a big one. A air cooled machine might be as fast as i liquid machine. The liquid keeps it at a consistent temp so the power is consistent.
ihaveobsessions is offline  
post #9 of 32 Old 12-24-2004, 11:29 PM
Member
 
Join Date: Oct 2004
Location: Iowa
Posts: 57
Yamaha > honda
John05raptor is offline  
post #10 of 32 Old 12-24-2004, 11:39 PM
Senior Member
 
Join Date: Aug 2003
Posts: 1,405
Quote:
Originally Posted by NitrousGuy
the fact that one is a sohc sesign, and the other is a dohc has nothing to do with being faster.
Yeah, I'm with you on this one. Older versus newer is a VERY lame explanation.

2004 YFZ450
RPyfz450 is offline  
post #11 of 32 Old 12-25-2004, 03:59 AM
Senior Member
 
Join Date: Sep 2004
Location: Southeast PA
Posts: 937
Send a message via AIM to YFM350 RAPTOR
Quote:
Originally Posted by The J
Lets see here: Why is the YFZ is faster than the 400ex?
1. The 400ex was designed how long ago?
2. YFZ has DOHC, EX has SOHC
3. The YFZ has extra 39cc
4. If I remember correctly the YFZ has a thinner piston skirt and a lighter piston all together.
5. Fourstroke technology has really increased in the time since the 400ex was released.
6. It's a Yamaha. Just Kidding

Over the past few years with the motorcycle and ATV industry steering away from two-strokes more R&D has been put into four-strokes allowing for larger numbers out of similar displacement engines. My uninformed $0.02 worth.


J
Prolly get flamed but what is DOHC and SOHC?

['04 350 RaptoR]
YFM350 RAPTOR is offline  
post #12 of 32 Old 12-25-2004, 07:05 AM
Senior Member
 
Join Date: Dec 2004
Posts: 101
Single Overhead Cam (SOHC)---Dual Overhead Cam(DOHC)
450rydr is offline  
post #13 of 32 Old 12-25-2004, 08:43 AM
Junior Member
 
Join Date: Nov 2004
Posts: 21
I think alot of the 4 stroke technology is trickled down from high performance street bikes also. The big four have some insane 4 stroke motors in their sportbikes.

Its the state of tune that the 400 and 450 are designed for.
Rider 414 is offline  
post #14 of 32 Old 12-25-2004, 09:11 AM
Member
 
Join Date: Aug 2004
Posts: 91
i know nothing really, but i thought water cooled motors could be run far more efficiently (leaner) than same sized air-cooled motors...a more efficient, complete burn = more hp, yes??

also, separating the exhaust timing from the intake with the DOHC design allows for far mre flexibility, yes??...imagine doing the "cam mod" on a SOHC motor...rotating the cam once to the left/right would change the timing ov every valve, not just the intake or exhaust side....

Finally, materials strength and parts reliability has increased so much...imagine running a stock ex400 up to 11,000 rpm..and that's just the limiter...

my two cents....and it may be all it's worth
lantz is offline  
post #15 of 32 Old 12-25-2004, 12:59 PM
Senior Member
 
Join Date: Aug 2003
Location: Northern Cali
Posts: 338
Send a message via AIM to The J Send a message via MSN to The J
Quote:
Originally Posted by RPyfz450
Quote:
Originally Posted by NitrousGuy
the fact that one is a sohc sesign, and the other is a dohc has nothing to do with being faster.
Yeah, I'm with you on this one. Older versus newer is a VERY lame explanation.
Older VS. Newer is a lame explanation?
I think it is a very reasonable explanation for more power being produced by the YFZ over the EX. The R&D put into small 4-stroke engines has acomplished a lot. The Yamaha engineers have engineered an engine that can withstand high RPM, severe abuse and be somewhat durable.
If you think about it the yz450f is better than the yz426f and so on. So with time things get better thats whats been happening all along. The 400ex was out and Yamaha one upped them with a faster lighter quad.
I don't quite understand you're argument of older vs. newer not being a valid explanation.

Merry Christmas


J

YFZ 450
The J is offline  
post #16 of 32 Old 12-25-2004, 01:05 PM
Senior Member
 
Join Date: Jul 2004
Location: Las Vegas
Posts: 345
Send a message via AIM to lvracer36
ccs dont mean sh1t, a piped yfz (450cc) will beat a piped DS (650cc), good ride on YFZ.

Venom powered YFZ
lvracer36 is offline  
post #17 of 32 Old 12-25-2004, 02:35 PM
Senior Member
 
Join Date: Mar 2004
Location: mass
Posts: 1,784
also, the power to weight ratio is unbeliveable, the yfz doesnt evin wya more then 370 lbs.. the banshee wich is a 2 stroke and 2 strokes weigh less are 280 lbs.. dont get me wrong the honda is a great machine, tis reliable i ahd one but i also had about a grand or 2 into it.. pipes,416 kit etc.. the yfz is made spicificley for the trrack and is race ready out of the box it just needs nerfs and a teather kills switch, i prefer yamaha for obvious reaosns tho.. IMO the only good thing about honda is reliablity, but a piped 400 ex is a lot faster and snappyer then a stock one

01 rm250.. completely macked out for sale.. 1800 or b.r.o
theblueYFZ is offline  
post #18 of 32 Old 12-25-2004, 04:43 PM
Senior Member
 
Join Date: Jun 2004
Location: Somerset, Pennsylvania
Posts: 738
Send a message via AIM to -LE-YFZ450 Send a message via MSN to -LE-YFZ450
DOHC- Duel over head cam, SOHC - Single overhead cam..

The YFZ has 5 valves, and 400ex 4 maybe?..

When in doubt, throttle out

Riding on -
2004 LE YFZ450
-Sparks
-hardstyle K&N airfilter kit
-Sparks needle 4th clip 175mj

'87 Bigbear 350, supertrap, K&N, DynoJet, warn winch, .040 over weisco, port/polished.
-LE-YFZ450 is offline  
post #19 of 32 Old 12-25-2004, 05:35 PM
Senior Member
 
Join Date: Jun 2003
Location: jackson, mi
Posts: 525
yea the older vs newer pharse is true. I bet even if they tried back in the eighties when the ex's motor was designed, they couldn't have got near the power out of a 450cc fourstroke that the yfz is making now.
ihaveobsessions is offline  
post #20 of 32 Old 12-26-2004, 02:07 AM
Senior Member
 
Join Date: Aug 2003
Posts: 1,405
Quote:
Originally Posted by The J
Older VS. Newer is a lame explanation?
I think it is a very reasonable explanation
I don't want to dwell too long on what's lame and what's not. I thought it was the most non descript explanation of the semi obvious.

2004 YFZ450
RPyfz450 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Yamaha ATV Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
faster 400ex Wolverine21 Other Models/Brands 15 06-07-2003 06:29 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome