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Discussion Starter · #1 ·
Has anyone compared the 2 heads side by side? I have and it seems to me the 05 head would be a much better choice for a race engine. Anyone have any input? The ports on the 05 are MUCH bigger. I know bigger isnt allways better. In talking with some porting specialist they have told me the 05 head is the way to go. A few of them even went as far to say throw the 06 head in the trash and get yourself an 05. Anyone got any input?
 

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I'm sure that head is worth somethin on ebay...

Sorry... my bad :p
 

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I didn't realize they're interchangeable. Don't quite get it because the crf motor is supposed to make more power, correct?
 

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I dont think they are interchangable....different stroke. plus I think the dowell pin thing's are in a different spot, so it wont fit on the 04/05 block.
 

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Originally posted by TRX450rlude@Nov 30 2005, 10:27 PM
I dont think they are interchangable....different stroke. plus I think the dowell pin thing's are in a different spot, so it wont fit on the 04/05 block.
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And the fact the carbie comes in on a different angle, so with a little work you could bolt the head on but join it to what?

Linc
 

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Discussion Starter · #6 ·
Im not tryin to bust chops here, but is anyone that actually knows what there talking about going to reply to this post. Please !

BOONE ? what are your thoughts ?

Anyone?
 

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its not going to work, they have different seats, different bores, different flow properties matched to that engine, the carb comes at a different angle, I bet there are a ton of other things that will make it not work that I am forgetting, or don't know. Also The Combustion chambe size and deck could be different resulting in either a higher comp ratio or a lower comp ratio.
 

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Discussion Starter · #8 ·
Listen im not trying to be an ass but i have had the 2 side by side and i can easily see what it would take to make it work. So what if the carb on the 06 is slightly angled more, less angle worked fine on the 05. Yeah the combustion chamber volume is a bit more on the 05 thats an easy fix too. All they did was take about 2 mm off the bottom of the head, thats easy enough to do. The most difficult part i can see is machining the cylinder stud holes to accept the dowel pins. They are oposite. I am just very curious if anyone has tried it and what there results were. Its easy to see the the ports are MUCH bigger on the 05. Is there any gain to be had there?
 

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as I said before, honda enginerrs probablly matched the heads best as they could to that specific engine. I doubt there would be a gain, honda would have done it on the dirtbike. thats a race ready machine that they need to be pretty perfect. Why not try it, I doubt anyone has, so there is no factual evidence that supports either my or your theory.
 

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Originally posted by motorhead@Dec 1 2005, 11:00 PM
Im not tryin to bust chops here, but is anyone that actually knows what there talking about going to reply to this post. Please !

BOONE ? what are your thoughts ?

Anyone?
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It will not work without MAJOR modifications.. totally different engines, inlet, outlet, combustion chamber ETC...

Somewhere on this site someone made a thread where the TRX and the CRF heads were compared... Somewhere... :dunno: I dont know how much differnet the 06 TRX is over the CRF though.
 

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Well I will say that it is possible, the heads are very close.....differences
A. 06 head is shorter..about 50 thou or so...this throws off timing chain lenth for one and brings valves closer to the head.
B. Combustion chamber has less volume on the 06
C. locator dowls are opposing, guess honda wanted to make sure you didnt mix them up...but easily retro.
The 06 head is better configured, with port entry and such, but has smaller cross sectional area. Not really worth the effort IMO, but I am sure it can be done without major effort. I have flowed both heads, and the 05 flows almost identical as the 06 until .300 lift, where the 06 shows just a tad bit more. I am sure this is from the anlge entry change. So there ya go. Is it worth the effort? Up to you to try!
 

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Yep, part of it, piston has around a .050 dome in the middle as well....just like the 05 crf.
 

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Discussion Starter · #13 ·
RageATV your telling me that the 06 head with the angled Intake port flows better at over 300 lift? how can an intake track flow better with the carb angled instead of straight on? I was under the impression the angle was because on the dirtbike it had to be that way so they just dealt with it on the quad. I think im just going to give it a try myself.
 

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Now this one really has me scratching my head. Would somone please explain to me why honda would make the newest designs worse than the prev years???? ( my point is that they would not)
Flow numbers?? what do they really tell you???
IMO a Flow bench will help you know if you have made an improvment or not.
But there is soooooo much more than flow numbers to consider.
Does anyone on this site have the capabillitys to test velocitys?
better yet Does anyone in the performance world have these instruments?
Do they have the abillitys to find Dead spots & unwanted turbulance in the flow path?
So once again I say to you the multi billion dollar companys Do have these instruments.
In closing id say that just because the port is smaller and shaped a little diferently does not mean it isnt better. Comon Guys use your noodles.


:popc1:
 

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Wow, few people in this one seem to know EVERYTHING but yet they have questions, Hmmmm :dunno:

And I thought I was a smartass :blink: .
 

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Ok I am going to add fuel to this fire :confused:


I have seen super moto crf motors with TRX450R heads.

The trx head will work on the bike motor, which I am the first to agree the CRF motor is not the same as a 2006 TRX 450r motor. The super moto engine builders found more horsepower by using the quad head (better flow).

The other thing it require some modifications how much or even what was done I have no ideal.


These crf motor are putting out almost 70 HP :cool: !
David
 

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Originally posted by 06T'REX@Dec 2 2005, 09:58 PM
Now this one really has me scratching my head. Would somone please explain to me why honda would make the newest designs worse than the prev years????      ( my point is that they would not)
Flow numbers?? what do they really tell you???
IMO a Flow bench will help you know if you have made an improvment or not.
But there is soooooo much more than flow numbers to consider.
Does anyone on this site have the capabillitys to test velocitys?
better yet Does anyone in the performance world have these instruments?
Do they have the abillitys to find Dead spots & unwanted turbulance in the flow path?
So once again I say to you the multi billion dollar companys Do have these instruments.
In closing id say that just because the port is smaller and shaped a little diferently does not mean it isnt better. Comon Guys use your noodles.


                                    :popc1:
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did you ever think they werent worried about the head design? If they are getting the power they want without having to make the head better then the 04 or 05 why mess with it? the 06 puts out more power stock then the 04/05 so Im sure they did not want to spend the money on R&D for the head. Also this is the head from the dirtbike. why change it? I can think of a hundred reasons why they dont need to make the head design better. ...The engine was designed for the dirtbike before it was the TRX. They designed the TRX head in 04/05 specifically for the TRX, not the CRF. So technically speaking the design of the 04/05 head is newer then the 06...
 

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Originally posted by motorhead@Dec 2 2005, 02:03 PM
RageATV your telling me that the 06 head with the angled Intake port flows better at over 300 lift? how can an intake track flow better with the carb angled instead of straight on? I was under the impression the angle was because on the dirtbike it had to be that way so they just dealt with it on the quad. I think im just going to give it a try myself.
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Yes, thats exactly what I am saying. I worked with another one today and I am pretty sure its because the intake valve is closer to the deck....less schrouding at high lift. NO, I never said the 06 intake port was angled.......The intake looks nothing like the traditional 03 04 crf engine. Straighter higher approach with a wider cross section. By all means, get one and try it...it could be the hot ticket.
 

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Now this one really has me scratching my head. Would somone please explain to me why honda would make the newest designs worse than the prev years???? ( my point is that they would not)
Flow numbers?? what do they really tell you???
IMO a Flow bench will help you know if you have made an improvment or not.
But there is soooooo much more than flow numbers to consider.
Does anyone on this site have the capabillitys to test velocitys?
better yet Does anyone in the performance world have these instruments?
Do they have the abillitys to find Dead spots & unwanted turbulance in the flow path?
So once again I say to you the multi billion dollar companys Do have these instruments.
In closing id say that just because the port is smaller and shaped a little diferently does not mean it isnt better. Comon Guys use your noodles.

Ok, let me use my noodle here.....funny.....I dont think I said the head was not as good as the old one...I justed stated my flow results. I believe that everyone that stays current with the current product realizes that Honda has put together a better package. I just let a few know what I found. Yes, I have a flow bench but I never thought to use a pitot tube or probe to check velocities or pressure drop. I just have a smurf on staff to walk inside the intake and yell at me.....HEY, THE AIR HAULING BUTT ON THIS SIDE. :hey: Sorry for the sarcasm, just thought that was a bit on the funny side. Really, IMO I like the 06 head better and I think there is more potential for power with it than with the older 04 05. But I am still not done working with it yet. I just dont think its a good idea to run out and buy one assuming it will simply bolt right on.
I already made the assumption with the cylinder. I bought a CRF Athena kit thinking it would bolt right on the 06......and no go. quite a bit different and by no means will it fit. Oh and by the way MOTORHEAD....guys like you are the reason people like me dont like to post anything on the forums. :wtf:
 

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Discussion Starter · #20 ·
First off RAGEATV what is it that offended you? I certainly wasnt trying. Sorry. One of my reasons for this post was just brought up by KyKult47. He says he has seen CRF motard bikes using the TRX head and those engine builders are CLAIMING 70 Hp. with this combination. Thats pretty much what i had heard as well. I have a friend that is PRO bike flattrack racer. I cant say who it is but he is one of the best. He rides an 05 CRF. Guess what? it uses the TRX head instead of the CRF head. He has Honda support behind him and THEY chose to use the TRX head instead. My guess is that there is a GOOD reason for it. The 06 engine was designed for a bike with certain restraints. The 05 for a quad without those same restraints. I was just looking for some educated input from others but like always in these forums it just becomes a bunch of BS.
 
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