Honda built 440ex vs YZ426f 450f???

[KEVIN300A]

Alright guys I am just needing some opinions right now I have a semi built 440!!! Cylinder|Head: RPM race port
Bore & Stroke: 89mm x 70mm
Displacement: 440cc
Cam: Hotcam stage 2
Carburetor: stock built by sore racing

I am thinking about picking up the chasis that is for sale in this thread that is ready for a 426 and switching over all my parts from my frame and picking up a yz426 or 450 motor.... I have NEVER ridden a hybrid and wondering if this is a good idea and if there will be a big power difference??? ANY suggestions and or ideas would be GREAT!!! thanks in advance!!!

[ss440ex]

First off nice quad!

The yz engine is also 20 lbs lighter.

There is a big difference in the power.....go for it.

Have fun.

Do a search for pics of my old 400ex/yz426.

[KEVIN300A]

I have full peps for it and the chasis I would be putting everything in is for sale by robertsracing87 Looks pretty clean I think it should be a pretty easy exchange if I find a good motor!!! Any other input is appreciated!! Will this be a lot of work besides just switching everything from one frame to the other??

[ss440ex]

I got a friend thats thinking of parting out his yz426f.

Engine has Hot cams

Pm me if ya want his ph#.

[250x_kyle]

i got a motor up forsale as well pm me if ur interested. motor carb wireing. motor has 40 hrs. yz450f decomp. cam, mild port and polish, kibble white valves and springs, kicker extender, and i have a knucle and lever laying around here somewhere. let me know

[KEVIN300A]

pm me a good price I already have 3 motors I am looking into!!!

[jrspawn]

You will be blown away by the differnce in overall power feel. The yz426 engines are screamers! They pack alot of hit for being the little brother to the 450's. The yz450f, well some may disagree but ive had about every quad, engine, and setup you can think of and the 03 yz450f engine i think is the best engine ever made from a viewpoint of reliability, power, and overall controllable delivery! The 4 speed trans is perfect for MX also. Its just a shame the engine came out right when the production quads were knocking on the door. The crf's being out earlier definetly stole the spotlight being pretty much the only 450 out there at the time(even though they were destroking them at that time)

Thank you
Justin

[CTmxyfz]

Ive been thinking of buying a yz setup frame and stuff and dropping my spare yfz motor into it.


Let me know if your interested in a fresh rebuilt yfz motor with kicker too.

[Derrick Adams]

The only difference between the 03 YZ and the YFZ is the crank, I believe. The transmission ratio of the 4 speed YZ is identical to the YFZ 2nd thru 5th. Another words, if you never use 1st it's just like the YZ.
I know the crank has to be beefier in the WR/YFZ to support the big starter/flywheel. Other than that, I think all the rest of the parts are the same. Now whether or not the YZ has a more agressive timing curve I don't know.

[jrspawn]

Originally posted by Derrick Adams
The only difference between the 03 YZ and the YFZ is the crank, I believe. The transmission ratio of the 4 speed YZ is identical to the YFZ 2nd thru 5th. Another words, if you never use 1st it's just like the YZ.
I know the crank has to be beefier in the WR/YFZ to support the big starter/flywheel. Other than that, I think all the rest of the parts are the same. Now whether or not the YZ has a more agressive timing curve I don't know.

Theres more difference than just the crank between the yz450f and yfz450.

Thank you
Justin

[2muchquad]

The 03 yz450 bike motor was(is) a beast.Its still faster than the new ones in the bikes now!i know i ride my buddys 07 yz450 and its tame compared to the wicked 03 450.Smooth and tractable 4 stroke power were words never used to describe the 03!Its the motor of choice for us power mongers..:devil:

[xrxmxcx]

Originally posted by jrspawn
Theres more difference than just the crank between the yz450f and yfz450.

Thank you
Justin

I am with Justin on this one there are many many differences between them, the crank is misleading to be the "only" difference. Possibly the only thing you have found along the lines. Look at them side by side, part by part.

On the other hand Kevin I have a bunch more parts that I found to go with the motor a bunch of odds and ends.

Thank you,

RMC

[Derrick Adams]

Ok, maybe this was too broad a statement. Lets tighten it up a bit.

Cams: My understanding is that the cams are the same with the exhaust cam advanced in the YFZ.

Cylinder: Bores are the same correct?

Crank: We know the differences in the crank

Transmission:
YZ:
1st (1.929)
2nd (1.563)
3rd (1.278)
4th (1.050)

YFZ:
1st: (2.416)
2nd (1.929)
3rd (1.563)
4th (1.278)
5th (1.050)

So thats the basics of an engine and transmission. Other than electric start vs. Kick start (which can be changed out on the YFZ, but never added to the YZ) what else is there?

Now, if you are refering to electronics, timing curves, etc. who knows. Obviously the YFZ is going to have a heavier flywheel to compensate for the heavier quad, but thats easily resolved.

This is a conversation not an arguement, just in case anyone takes offense to this post.

Also check out... http://www.thumpertalk.com/forum/showthread.php?t=287108&highlight=transmission+gear+ratios

When I switched from 400ex to yz hybrid the gain in hp was huge. I couldn't get it started so I push started it down a hill. Soon as it started up I hit the throttle and it took off so much faster than I expected cause I was used to the 400ex that my hands nearly got ripped off the bars.

[jrspawn]

Again, there are much more differences than what you read on the internet. Somehwat same theory on certain parts, but again compare parts hand in hand and there will be differences.

You should ride both of the engines, after that you would realize that they are no where even close to the same or even similar. Most people just read that the 4 speed is just a yfz bottom end with no first, again ride it and you will be blown away.

Ive owned and built almost every type of quad/hybrid/4 stroke powerplant quad out there, and theres a reason i say hands down the 03 yz450f was the best engine built. Its just a shamed it came out too late for the hybrid scene as production quads were here and the crf stole the spotlight being out earlier.

Thank you
Justin




Originally posted by Derrick Adams
Ok, maybe this was too broad a statement. Lets tighten it up a bit.

Cams: My understanding is that the cams are the same with the exhaust cam advanced in the YFZ.

Cylinder: Bores are the same correct?

Crank: We know the differences in the crank

Transmission:
YZ:
1st (1.929)
2nd (1.563)
3rd (1.278)
4th (1.050)

YFZ:
1st: (2.416)
2nd (1.929)
3rd (1.563)
4th (1.278)
5th (1.050)

So thats the basics of an engine and transmission. Other than electric start vs. Kick start (which can be changed out on the YFZ, but never added to the YZ) what else is there?

Now, if you are refering to electronics, timing curves, etc. who knows. Obviously the YFZ is going to have a heavier flywheel to compensate for the heavier quad, but thats easily resolved.

This is a conversation not an arguement, just in case anyone takes offense to this post.

Also check out... http://www.thumpertalk.com/forum/showthread.php?t=287108&highlight=transmission+gear+ratios

[KEVIN300A]

I picked up a yz426f and going to put that in a EX frame by the sounds of it I should be pretty happy I am getting off from a 450r so I hope I am not to dissapointed!!!

[jrspawn]

Originally posted by KEVIN300A
I picked up a yz426f and going to put that in a EX frame by the sounds of it I should be pretty happy I am getting off from a 450r so I hope I am not to dissapointed!!!


Youll be more than happy id say. The 426 is a very snappy stout engine. As where the 450r has a smooth mellow power.

[AB250R]

THE 426 IS THE ONLY WAY TOO GO ONE THE HYBRID THEY HALL THE ALL AROUND POWERE BOTTOM TOP AND MID DAMN CANT GET ANY BETTER IF IT WASNT X MAS TIME ID HAD ALREADY PUT MY 2 CENTS IN ON THIS QUAD ITS THE CLEANIST THAT IVE SEEN ON THIS FORUM YET.... AND I HAVE RODE ONE PLENTY OF TIMES THEY RIDE LIKE YOUR ON CLOUD 9...!

[KEVIN300A]

I will be getting my motor and stuff in the next week or so... I will def. keep you guys posted on my build!!

[liex21]

im planning on doing the same thing also ive been looking into it for sometime now just doing my research. my friend has a yz426 engine in his hybrid and its just a totally different world compared to the 400 engine then again i dont know how yours felt with the engine mods you have but the 426 definetly hauls i like the power delivery alot better on the 426 i love power that just slams you back and makes you hold on and the 426 does that.goodluck cant wait to see how it comes out

[KEVIN300A]

thanks man... I am pretty excited to get it going... does the 426 have problems keeping up with a trx450r with some mods... obviously rider is a big deal but just in general how do they compare??

[jrspawn]

Originally posted by KEVIN300A
thanks man... I am pretty excited to get it going... does the 426 have problems keeping up with a trx450r with some mods... obviously rider is a big deal but just in general how do they compare??


Power wise, not a problem at all compairing the the 450r.

Justin

[jrspawn]

Stock to stock the yz426 engine already puts down mre HP down than the 450r engine, its much esier to get it into the 50hp range also.

Justin

[CSR400EX]

Originally posted by KEVIN300A
thanks man... I am pretty excited to get it going... does the 426 have problems keeping up with a trx450r with some mods... obviously rider is a big deal but just in general how do they compare??
to answer that, here is a vid of my old 426 racin my buddies 04 450R with a HRC kit and slip on. the camera is at 300ft, after we pass the camera i pulled 5 to 6 bikes on him easy.

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[KEVIN300A]

Nice I cant wait to get this build going!!!

[KEVIN300A]

Well I took the plunge all the parts are in the mail and should be here tomorrow!!! I ended up buying a frame that was set up by SS440ex he seems like the man when it comes to hybrids... some other goodies will be PEP big bottles, +3 +1 Housers, hipers, Laeger +1.25 swinger, and using the other parts from my 400ex to complete the project... I will be sending out for powder in the next couple weeks and I will be doing shocker yellow and black scheme... trying to decide if I should do frame, subframe, arms, swinger all shocker yellow or brake it up and do the frame gloss black with the covers on the motor yellow to set it off... what do you guys think?? I will be running my silver plastics!!

[KEVIN300A]

shocker yellow!!

[Quadforce]

sounds like a really nice project..

[KEVIN300A]

Quadforce what do you think?? Should I do it like yours where you have everything orange should I go shocker yellow?? Or should I do everything shocker yellow with a gloss black frame?? I am doing my valve cover and other covers to the motor also in shocker yellow idk if it will be too much though!!

[Quadforce]

Originally posted by KEVIN300A
Quadforce what do you think?? Should I do it like yours where you have everything orange should I go shocker yellow?? Or should I do everything shocker yellow with a gloss black frame?? I am doing my valve cover and other covers to the motor also in shocker yellow idk if it will be too much though!! IDK.. that color is bad to the bone... I kinda think my cases are a bit much.. that is why I put everything billet on them I could get.. I did it because I could not chrome them because they are magnesium... other than that I would stick with the shocker yellow and chrome maybe use a accent color to mix it all up( maybe silver or gray to match your plastic ).. I do not like black frames because of how they show dirt.. it is just like car.. after you wash if you do not wipe every inch of it down it spots and is just a pain IMO.. had one before do not want another. chrome is nice because it hoses off pretty easy and is tough and looks good. It means alot that you even asked my input.. that makes me feel good.