CRF Conversion

[Baxter]

Just bought 04 CRF 450 engine with carb,full electrics and exhaust.
Do I Fit CRF ignition onto 04 450R or fit complete engine into 04 TRX chassis.Is it worth swapping engines.:confused:

The crf motor is way faster than the trx

[MX450]

but it wont fit directly in your frame without mods

[dirteater74]

I'm following you around with this post trying to get more information on the CRF ignition also. Is this mod really worth doing or is getting an aftermarket CDI just as good or better?

[fox17]

depending on the mods necessary i would put the whole crf engine in it. that engine rips.

[xsr_racing28c]

I'm pretty sure that putting a crf block into a trx chassis would make you illegal for AMA rules in production class but i'm not 100%. I believe you have to have stock trx cases.. But i'm thinking they don't look too much different so who would know.
~Jay

[Baxter]

Racing in English motocross anything goes.:devil:

[MX450]

by the time you did all the work to make the motor fit in the frame, you mine as well just keep the ignition, sell the crf motor and mod out your trx motor, you can make it faster than a stock crf motor anyways with the right mods

[fox17]

but a modded crf motor is a badder motor.

[R3Concepts]

Originally posted by fox17
but a modded crf motor is a badder motor.

This is a negatory.

[Architects]

I think he meant badder as in more badass.

[R3Concepts]

Originally posted by Architects
I think he meant badder as in more badass.

Still a negatory.:D

[stocktires]

Originally posted by R3Concepts
Still a negatory.:D

do tell why?

CRF motors are SICK! Definatley do the swap! It's been done before and doesnt seem like it would take much to do.

[R3Concepts]

You can build a CRF motor up and make 50 ish. The last one I did was for my brothers Lonestar Hybrid. Maybe in the 48ish range.

My last TRX stock bore layed down 63 today on U4.

The CRF does not have the components that it needs to make it a good MX quad worthy motor. The parts are light and it revs to the moon and quickly, but a properly built TRX motor will hand a CRF its arse.

[stocktires]

Originally posted by R3Concepts
The parts are light and it revs to the moon and quickly

Which is why I love it, it has enough torque (tons) yet revs crazy fast and quickly. Only making 50hp thats total BS, a stock CRF would pull 47 on a bad day, on PUMP gas. And a CRF has more than enough torque for anyone.
An EXTREME TRX motor on U4, making 63, I can agree with, but thats the limit, pass that is BS too.
Seriouly, both motors are close when heavily modded, but stock for stock a CRF will SLAUGHTER a TRX. Also, the 05 and earlier motors are a disgrace, seriously.
And sorry buddy, but 15 more HP on the TRX vs. a CRF is COMPLETE BS, Its close to the same motor when built up.

[4ABURN]

Originally posted by stocktires
Which is why I love it, it has enough torque (tons) yet revs crazy fast and quickly. Only making 50hp thats total BS, a stock CRF would pull 47 on a bad day, on PUMP gas. And a CRF has more than enough torque for anyone.
An EXTREME TRX motor on U4, making 63, I can agree with, but thats the limit, pass that is BS too.
Seriouly, both motors are close when heavily modded, but stock for stock a CRF will SLAUGHTER a TRX. Also, the 05 and earlier motors are a disgrace, seriously.
And sorry buddy, but 15 more HP on the TRX vs. a CRF is COMPLETE BS, Its close to the same motor when built up.

I would have to agree my 04 CRF motor is way stronger than my 06 trx. You can tell this just by nailing the throttle in neutral, let alone after putting it in gear!!!!!!!!That bike ran a 13.1 in the quarter at 96 miles with a 15 tooth on it. I hit 84 at eight mile.this is crazy fast. I know weight right, but you can telll if you put the CRF motor in the TRX it would deffinatly be faster. I do not know if the tranny would take it,but you would find out. I say giver.:D :D Thats just my 2 cents.;)

[tooanxiousii]

The crf 450 and the 06,07 trx450r have the same motor put two things the TRANS and the CAM.. That is why they feel different

[stocktires]

Originally posted by tooanxiousii
The crf 450 and the 06,07 trx450r have the same motor put two things the TRANS and the CAM.. That is why they feel different


Thats a freakin joke....right?

[Vader]

Ahhh the Legendary CRF hybird conversions... kinda like the infamous Quadzilla. Thought to be some of the "baddest bikes of all time" and who's legendary status grows with time...:huh

The truth is the CRF conversions are not putting down any more (and often less) HP / TQ than a properly set up TRX. I have posted dyno's of the Legend @ .org. A well set up 03 CRF hybrid with HC2 that one of my duning buddies has puts down 46.7HP / 31.7TQ.

On the same dyno an 06 TRX with an HRC kit + HC2 puts down 47.5HP / 32.5TQ.

My pump gas 05 TRX with HC2, bored carb, and ported head puts down 50.9HP / 33.3TQ - same dyno too.

These are facts, and I know it is hard to believe that the dirtbike engine is not killing the TRX based engine, but some of us know first hand from dynotuning experience and from straightline racing. I have ridden the LEgend too, and yes it is fast, but when we line up, sorry but my TRX just walks away from it. You can check out these dynoraphs in the engine forum at .org.
:D

[R3Concepts]

Originally posted by stocktires
Which is why I love it, it has enough torque (tons) yet revs crazy fast and quickly. Only making 50hp thats total BS, a stock CRF would pull 47 on a bad day, on PUMP gas. And a CRF has more than enough torque for anyone.
An EXTREME TRX motor on U4, making 63, I can agree with, but thats the limit, pass that is BS too.
Seriouly, both motors are close when heavily modded, but stock for stock a CRF will SLAUGHTER a TRX. Also, the 05 and earlier motors are a disgrace, seriously.
And sorry buddy, but 15 more HP on the TRX vs. a CRF is COMPLETE BS, Its close to the same motor when built up.


What motor building experience do you have? Hate to say it but I build motors all day long. And your assumptions are 100% incorrect.

Mod for mod a TRX will pull more power all day long. A stock CRF motor will NOT pull 47 in a quad chassis. The best stock bore stock stroke, built to the gills CRF was a 52 HP bike, and didnt make arse for TQ.

Now, we do have a 545 CRF on Alky in a Lonestar drag chassis that we use for a hill bike. It makes 67 on motor. My gas stock bore makes 63 and is a hill bike as well. And its got more in it.

Hell DASA is making 70 with a stock bore, stock stroke TRX on gas. Why dont you ask him what he thinks of CRF motors.

Theres only one guy that Ive even seen in the 60 range with a stock bore CRF and thats Ron Hamp.

Have you dynoed your CRF? I would like to see what it makes.

[Baxter]

The two engines in comparison are ;

04 trx450r stock fitted with 13:1 wiseco piston ,full HRC kit plus micron exhaust

and

04 crf 450r completely stock motor.

Some are saying put the crf in the trx chassis but if I put crf ignition on the trx would it be better then the stock crf?