CRF450 Carb good deal or not

[Chanman420q]

I did a search and got the jist of the idea. You buy the carb from service honda, the 03 model, not the 04 cuz its 35 bucks cheaper, then u buy a yfz450 throttle cable as it fits good on the carb and on the 400ex thumb throttle. Then to get rid of the hot start and Throttle positioning sensor ( which i have no clue what it does ) u buy new cases from rocky ridge for around 30 bucks. then u gotta get new air boot because the carb is to short, so theres another 20 or so bucks. And on top of that u got to shimmy ur gas tank up a tad so it clears it.

So lets look at this..

Carb - 370 from Service honda
YFZ throttle - 20 from dealer
Cases - 30 - rocky ridge
longer air boot - 20 or so - no idea where to get it

so its about 440 bucks give or take a few just to get the carb adapted.... is it really that good of an idea?

everyone says it makes more power and is cheaper, but in the long run to get it to work its not that much cheaper and way more of a hassle as aposed to the 39mm.

maybe im wrong.. i wanna get the most bang for my buck, so maybe someone can set me strait

[Atreyu]

Why not just buy an aftermarket 400ex carb?

[Narly R]

I NEED an explaiation here, i dont understand where I can get a boot, and how it needs to fit. My sposer UPPracing makes air boots, so I am going to see if they can make me an aftermarket one. I have a 250r throttle cable, will the yfz cable still work? What about a trx450r cable? I mean the carbs are the same right?


:confused:

[woprs50]

does anyone have a link to the article that says it actually flows better than the fcr41? i really need a bigger carb and i need to get one soon im either gonna go with the 40 or the 41 but i would like to know what im getting into with trying to put the 40 on


do you have a link to Rocky Ridge or where ever you get those cases from ??

i cant find anything on trying to do this :confused:

[Chanman420q]

Originally posted by Atreyu
Why not just buy an aftermarket 400ex carb?

thats what i was thinking, but the fcr40 flows better than the 39 and 41mm, and on top of that its cheaper to buy the carb outright, what i am getting at is, from what i said in my original post is that all true? because if it is then im sure the 39mm is fine.

[cals400ex]

rocky ridge doesn't have a site. you need to call them. however, they highly recommend the 40mm over both the 39 and 41mm fcr's. they say on the flowbench the 40 flows more. they really talk up those lectrons but he wouldn't recommend them on a cross country bike. i will be getting a fcr 40mm here soon hopefully.

i don't know where to buy the air boot from though?? i think you can get it from rocky ridge but he is anal about telling you this stuff if you don't buy it from him.

[Chanman420q]

now what does the throttle sensor do and the hot start? does it have to be taken off or can u leave it on

[woprs50]

im not sure but i guess ill figure it out im gonna order one from service honda first thing tomarrow morning then i guess ill let you guys know once i get it

does anyone have the number to rocky ridge where i can get those cases if i need them ? you can PM them to me if you want


i think im gonna be going to the Yamaha dealer here in the next few days so what is the model number of the yamaha 450 ? so i can get a throddle cable :confused:

[cals400ex]

Originally posted by woprs50
im not sure but i guess ill figure it out im gonna order one from service honda first thing tomarrow morning then i guess ill let you guys know once i get it

does anyone have the number to rocky ridge where i can get those cases if i need them ? you can PM them to me if you want


i think im gonna be going to the Yamaha dealer here in the next few days so what is the model number of the yamaha 450 ? so i can get a throddle cable :confused:


i would order a 03 or 04. in 03 they changed the diaphram. i think it has something to do with how long the fuel squirts or something. however, i think i may have my hands on a 02 but i just need to get this new diapram. i think it only costs $15 to $20 so i am not too worried.

here is rocky ridge's #: 270-259-9604

this carb is off the honda crf 450 dirtbikes. i am not sure if this carb comes on a yami bike or not.

[cals400ex]

Originally posted by Chanman420q
now what does the throttle sensor do and the hot start? does it have to be taken off or can u leave it on


i don't know all the details but you are just suppose to plug them off. these items aren't used on our 400ex's. i think you just plug them with whatever you prefer. i was told that rocky ridge does sell these block off plates but i don't know what they look like.

[woprs50]

well i just ordered my 40mm from service honda it should be here Wednesday ill figure it out from there

[cals400ex]

make a post to let us know how everything goes

[F-16Guy]

Originally posted by Chanman420q
now what does the throttle sensor do and the hot start? does it have to be taken off or can u leave it on
The TPS (throttle position sensor) is used to change the ignition timing on bikes with that capability to get the best power at a given RPM and throttle setting. It makes no difference on the 400ex, you just leave it unplugged. The hot start button is kind of the opposite of a choke, it leans the idle circuit when you stall your bike when it's hot. You probably won't need it, but I don't think you have to take it off.

[z400ACDC]

Guys, I could use some advise. My nephew has a 400ex with web cam and ported head. It has a lectron on it and it runs good , but he thinks a 41 fcr would make a little more bottom. What do you think?

[cals400ex]

the lectrons make awesome power, probably the best power of any carb. however, they are susceptable to dirt and seem to be higher maintenance. also, the lectrons don't have accelerator pumps so yes you will lose some bottom end power with that. personally if you are looking for bottom end power i would consider the stock carb or a fcr 39. i haven't used the 41 before but it would only make sense that it would make less bottom end power when being compared to the other two.