Questions for guys running FCR carbs

[flyboy1294]

I got my FCR in the mail today... from what I can tell it mounts up ok. I was pleasantly surprised to find that it had one of those fuel screws, wasn't expecting that.

I do have a few questions though,
What kind of throttle cable did you use?

And are these wires and plugs coming out of it for? What do you do with them? I have never dealt with anything like this before.

Thanks in advance

[4reeds]

I had mine made.Cost $15

[flyboy1294]

Originally posted by 4reeds
I had mine made.Cost $15

The throttle cable I'm assuming.

Where did you get it done? Also, any idea on the wires? These concern me the most, but everyone must find something to do with them.

[4reeds]

Sorry, Mine is an fcr flatside carb.I believe its from a yamaha.It doesn't have any wires.Is it for the throttle positioning sensor?

[flyboy1294]

Originally posted by 4reeds
Sorry, Mine is an fcr flatside carb.I believe its from a yamaha.It doesn't have any wires.Is it for the throttle positioning sensor?

In the diagram it does say throttle sensor... Do you know if the bike would run without it hooked up? If not, am I screwed or what? I took a chance and went with a dirtbike carb. :eek2:

[bkelley]

You don't need the TPS. Just leave it unplugged.

[flyboy1294]

Originally posted by bkelley
You don't need the TPS. Just leave it unplugged.

Excellent to hear. :chinese:

Just out of curiousity, how does it function when installed on the bike?

[underpowered]

since the carb is stand alone from the TPS, no you dont' need it. leave it un plugged. no harm done.


my cable on mine came with the carb when i got it, no idea where i could find a replacement though.

mine made a HUGE difference. throttle response is great, more power throughout the power range. upped the size of my leak jet to get rid of the low end bog that is common with these carbs. mine is an FCR 41mm.

[flyboy1294]

Originally posted by underpowered
since the carb is stand alone from the TPS, no you dont' need it. leave it un plugged. no harm done.


my cable on mine came with the carb when i got it, no idea where i could find a replacement though.

mine made a HUGE difference. throttle response is great, more power throughout the power range. upped the size of my leak jet to get rid of the low end bog that is common with these carbs. mine is an FCR 41mm.

Thanks, exactly the help I need.

Mine is a 40mm FCR. I figure I have a few options... I can either get the stock CRF cable, maybe a YFZ cable, or maybe a 450r cable.
- I know that the 450r cable works on the 450r carb everyone is doing, but I don't know about an FCR.

What is your carb off of?

[underpowered]

mine is one made for the 400ex. it was bought from curtis sparks racing i believe for the 400. i got it 2nd hand, but know the PO of it and i know he bought it brand new for his 400.

[flyboy1294]

Originally posted by underpowered
mine is one made for the 400ex. it was bought from curtis sparks racing i believe for the 400. i got it 2nd hand, but know the PO of it and i know he bought it brand new for his 400.

Alright I'll look into that. But since it's from Sparks, it's bound to be over $100 :D

[400man]

I got some questions about the FCR carbs....figured I might just ask it here instead of making a new topic...

are the FCR carbs on the honda 450r (06 and newer) and yamaha yfz450 different or pretty much the same?? and could a yfz450 carb be used on a 400ex?? and will the FCR carb throttle cable work with the 400ex thumb throttle, or would I need to get a 450r or yfz thumb throttle.

and would it be a bad idea to use a 39mm FCR carb on a stock motor? like would it just be too much air/fuel for it to handle and just make it run awfull compared to a 400ex carb? I am planning on getting some motor work done in the near future ( high compression 416 with stg2 cam, etc), but was kinda wanting to get one of these FCR carbs and see how much of a difference they make. I have seen some pretty good deals on yamaha yfz450 carbs.

[flyboy1294]

Originally posted by 400man
I got some questions about the FCR carbs....figured I might just ask it here instead of making a new topic...

are the FCR carbs on the honda 450r (06 and newer) and yamaha yfz450 different or pretty much the same?? and could a yfz450 carb be used on a 400ex?? and will the FCR carb throttle cable work with the 400ex thumb throttle, or would I need to get a 450r or yfz thumb throttle.

and would it be a bad idea to use a 39mm FCR carb on a stock motor? like would it just be too much air/fuel for it to handle and just make it run awfull compared to a 400ex carb? I am planning on getting some motor work done in the near future ( high compression 416 with stg2 cam, etc), but was kinda wanting to get one of these FCR carbs and see how much of a difference they make. I have seen some pretty good deals on yamaha yfz450 carbs.

No problem,

The YFZ carb is a 39mm FCR. I know that for a fact.

I was told that the 06+ 450r carbs were 40mm FCRs. So they might be a bit different.

I don't know about the the throttle cables, I have the same question... However, I do know that for many, the YFZ is the carb of choice. It will definitely fit.

I think it will still run, but you will have to jet it for stock settings, then rejet when you mod your engine. Keep in mind though, you will not see much power increase with a stock motor. It's when you do the upgrades that the carb will make a big difference.

That's all I know so far, hope it helps

[ish416]

I am running an 06 Honda 450R FCR carb and the only thing I did was change the jetting and get an 06 450R throttle cable.

It works perfectly. One of the best mods you can do to a lightly modded EX for the money. The FCRs have much better throttle response and seem to have a lighter throttle pull than the stock EX carb has.

Also, have a few friends with YFZ450s that have switched their thumb throttle over to a 400ex/450r/300ex thumb throttle as they seem to have a much lighter pull than the YFZ throttle.

[flyboy1294]

Originally posted by ish416
I am running an 06 Honda 450R FCR carb and the only thing I did was change the jetting and get an 06 450R throttle cable.

It works perfectly. One of the best mods you can do to a lightly modded EX for the money. The FCRs have much better throttle response and seem to have a lighter throttle pull than the stock EX carb has.

Also, have a few friends with YFZ450s that have switched their thumb throttle over to a 400ex/450r/300ex thumb throttle as they seem to have a much lighter pull than the YFZ throttle.

I just ran the part numbers and 06+ 450r carbs are identical to the CRF carbs. Both are 40mm FCR carbs with TPS.

So I'm going to order a 450r cable and cross my fingers lol. But it should work.

[sc400ex_rider]

ya i used a yfz450 cable with mine. i sent the carb back and got the 04-05 450r carb. i used the same cable on both so they are interchangeable.

[400man]

so just to clarify some things, I could use a yfz450 carb and throttle cable just fine. will the carb fit in the intake boots like the stock 400ex carb or would i need to "make" it fit? and would I have any problems with the carb hitting my gas tank? cause I have a clarke 5.5 gallon oversize tank and it comes well over my stock carb pretty close.