Best hybrid motor?

[A A R O N]

Okay, right now i've got an lsr 250r and i'm really looking at going the hybrid route. The number one best situation for me would be to get rid of the r and get a 400ex to chop up cause i really dont want to kill a dying legend. But, if it comes down to it i may have to use the r frame. What im wanting to know, is, for the 400ex frame, what are some of the better options for a motor? I've looked at the crf450, yz450, yz426, and yz400....i just need to know the best out of these and if im missing any. I know the crf wont fit in the r frame, but i'll most likely use the 400 frame anyway. If im not mistaking, the 426 was only made for a couple of years, and parts would be kind of scarce. Is the yz400 any improvement over a plain 400ex motor? What kind of reliability issues have been experienced with these motors?

Sorry for the long post....any help would be greatly appreciated.

[quadmxracer]

If you can I would get the CRF450 engine for a 400ex frame or if you can afford it go with an aftermarket chassis for strength. But I had JB Racing do my 400ex frame and it has held up extremely well. I haven't rode it much to tell you the truth as I just finished not too long ago but I has held up thus far. Jody does an extremely nice job on the ex frame for that setup. The engine has tons of power, you won't be dissapointed. Here are a couple pics of mine.

http://www.imagestation.com/picture/sraid203/p135cd1e84d275e5ba68ade180b1c84f2/ef9d3ed8.jpg
http://www.imagestation.com/picture/sraid203/p2651ed01c5322ed284d1730eb13d23d0/ef9d3e11.jpg

-Clayton

[ss440ex]

You use the words (and get a 400ex frame to chop up)......
How is welding in two engine mounts a chop up?????
When you do this conversion,where is all the chopping at?????

[quadmxracer]

Yeah exactly. There isn't a whole lot to it to be honest. The 400ex frame has plenty of room for the CRF considering a big air cooled unit was in there at one time. All you have to have done is cut out the original lower engine mount and have a new one put in to accept the CRF450 (NOTE: make sure you tell whoever is doing your frame the measurement of the lower mount on the engine so they can get it right as Honda changed if from 02/03 when they came out with the 04 which is different), along with having tabs added to the upper frame rails for the head stay mount. Gusseting is something you should do to the frame also at the same time.

[ss440ex]

Originally posted by quadmxracer
Yeah exactly. There isn't a whole lot to it to be honest. The 400ex frame has plenty of room for the CRF considering a big air cooled unit was in there at one time. All you have to have done is cut out the original lower engine mount and have a new one put in to accept the CRF450 (NOTE: make sure you tell whoever is doing your frame the measurement of the lower mount on the engine so they can get it right as Honda changed if from 02/03 when they came out with the 04 which is different), along with having tabs added to the upper frame rails for the head stay mount. Gusseting is something you should do to the frame also at the same time.

And your done....
:)
Some make it sound like a butcher or a hack job.
BTW Thats a very nice quad!!!

[450r51]

ktm 525sx all the way!

[400exrider707]

I thought with the CRF motors you had to cut the tube on the back of the frame where the rear shock mounts. I thought it was blocking the path of the carb? maybe its on a 250R frame Im thinking of this, but Im almost certain a member on here had to do it.:confused:

i heard the yz motors mount up much easier than the crf motors.

also i heard the yz motors are more relible compaired to the crf.

i also heard somthing about the crf motor having valve problums and i heard of the yz motors having clutch problums.

im hibriding my 400ex and im going to use the yz motor only because the yz motor you can pick up for like $1000 less than a crf but i wish i had the money for the crf.

i say crf450 if you have the time and money.

also xr650 motors fit also but not to good for mx

[quadmxracer]

Originally posted by not z?
i heard the yz motors mount up much easier than the crf motors.

also i heard the yz motors are more relible compaired to the crf.

i also heard somthing about the crf motor having valve problums and i heard of the yz motors having clutch problums.

im hibriding my 400ex and im going to use the yz motor only because the yz motor you can pick up for like $1000 less than a crf but i wish i had the money for the crf.

i say crf450 if you have the time and money.

also xr650 motors fit also but not to good for mx

The YZ motors also are known for valve train issues. As to reliability of the CRF its actually really good. Both are pretty good in that area if you ask me, I'm saying use your head and perform proper maintence on these engines as you have taken them out of their original application. Oh for the CRF the only thing you have to cut out and not use is the the front cross bar on the sub frame to allow for the air boot to line up better with the carb. I had to get an adapter that went from the engine to the carb that pointed the carb up a little better and it all went together well for me atleast.

Originally posted by 450r51
ktm 525sx all the way!
im with ya
:D

[ThorR88]

how much would it cost to build a hybride if you already have a 400ex like how much would the final price be after like you get the motor and what not.....thanks

Originally posted by ThorR88
how much would it cost to build a hybride if you already have a 400ex like how much would the final price be after like you get the motor and what not.....thanks

depends what motor you go with.

say you picked a yz400 motor.
motor $800
mounting kit $260
radiator$40


right their you have pritty much everything needed

[ThorR88]

is it worth the money and where do you get the motors?

Originally posted by ThorR88
is it worth the money and where do you get the motors?

ss400ex sells the kits.

worth every penny

also need to buy or make a kick start extender. they cost $200 from a compiney

[hontrx265r]

I've never run a crf engine, but I've had great success with my 426(bored to 440) I've had this engine for about three years with no major issues, had to replace a trans gear once (however i got lucky and the piece that broke go lodged under the oil pump and never went through the motor) I did a conversion to an arens frame and now I'm building this lonestar frame with laeger t-pin and loving it. I've got the top end down now putting in ported head and 13:5:1 piston.

[hontrx265r]

moving slow but going well!

[NacsMXer]

Originally posted by hontrx265r
moving slow but going well!

Damn that thing is nice!! :eek2: A Laeger T-pin front end is my dream front end....drools... I like the copper side cases and head cover, is that PC?

[ss440ex]

You can also do the kicker extensions alot cheaper.:)

[ThorR88]

ss400ex?

[hontrx265r]

The side cases are indeed copper pc'd...I got the t-pin for 400.00, but it was SLOPPY to say the least. I found a local bearing distributer and replaced everything for less then half of what laegers charges to do one spindal. Ever bearing, bushing and zerk is new. got it all pc'd and now she is pristine. Front elka's are getting serviced right now, I've also got matching new klaws for the rear.. I'll keep posting pics here and there as it comes along.

[Iliketogofast]

I think if I were you I would make a KTM hybrid. They are original and very trick.

[zeppelin]

Originally posted by 450r51
ktm 525sx all the way!
that would be my first choice
if not that, than an '04 yz450, those beasts are MEAN!

[jrspawn]

Hey, as for which powerplant i would say is the best. Hands down the 03 YZ450 4 speed bike engine. Ive owned pretty much every type and kind of hybrid imagineable, including pretty much every type production quad, and the yz450 engine is the best of all. The gearing is spaced perfectly, pretty much i ride almost every mx track in 3rd, the whole time and never shift(other than starts) and it has more than enough power and pull for everything. And is the most reliable engine ive ever owned! Unfortunetly personally ive had nothing but bad luck with the honda powerplants(might just be my luck) so im very sour to them. Ive had over 10 different YZ engine's(from 400-450) and have liked them all, just the YZ450 tops them all. in conclusion, if you power and more reliablity, go with the YZ450. The only downer, you'll probably have to buy the whole dirtbike to get an engine.

Justin
jspawn@aol.com