fcr carb not good for xc

[jeepnrocks]

just kind of curious about this one. i recently found a sparks 41 mm fcr for my quad. im gonna test it out obviuosly but i have heard a few people say it was too twitchy for xc and it tired them out alot easier. any thoughts on this ? lets hear from all the xc guys

[atcyalater]

When they say twitchy they probable are talking about the jetting. Because FCR carbs have an accelerator pump they can be hard to jet. The FCR carb is far superior to the carb that the TRX450 comes with. All high performance four strokes come with a FCR carb today. It doesn't matter what manufacturer, they all use them for both motocross or off road bikes. Honda uses a FCR on the CRF450X dirt bike. I'm not sure why Honda was being so cheap with the TRX450R by not putting a FCR carb on the bike. I suppose they were trying to save money. I would suspect, to try and keep up with performance advantage the Yamaha YFZ has, they will start putting FCR carbs on the TRX450R in the future.

[beak7707]

I would say it would be true. From what I have heard and read the YFZ is 2 stroke like because of the FCR carb. That carb is much snappier than the stock R carb.

[bobbo97f150]

I'm not real sure on what FCR stands for or how it is actually better but I think the stock 450R carb has an accelerator pump. When I hit the throttle on mine there is a rod that gets pushed down towards the float boal which manually squirts fuel down the barrell of the carb. If thats what an accelerator pump is, stock 450Rs have it as well as stock 400EXs. Who all actually knows the difference between and FCR carb and a regular carb? Could you explain it to me?

[450 Racer R]

i think everyone was switching to the fcr carb because it's a smaller diameter which means more throttle response

[rowlrag]

Originally posted by bobbo97f150
I'm not real sure on what FCR stands for or how it is actually better but I think the stock 450R carb has an accelerator pump. When I hit the throttle on mine there is a rod that gets pushed down towards the float boal which manually squirts fuel down the barrell of the carb. If thats what an accelerator pump is, stock 450Rs have it as well as stock 400EXs. Who all actually knows the difference between and FCR carb and a regular carb? Could you explain it to me?
It does have one.:)

[WhiteZee]

Originally posted by atcyalater
I would suspect, to try and keep up with performance advantage the Yamaha YFZ has, they will start putting FCR carbs on the TRX450R in the future.
you are wrong. the fcr will not make any more hp then the stock 450r carb untill your running something like 500cc 14:1 comp, and +2 +1 valves. it mainly gives better throttle responce which could possibley tire some people out.

[lukester720]

Whitezee is correct, I have the FCR on my quad and it has more "snap" or throttle response to it than the stock carb which will wear you out faster. A good XC machine will have a smooth powerband and smooth suspension that won't beat you to death!:cool: The stock carb is also has the butterfly choke which cuts back on the air velocity coupled with the fact that the air has to travel a little further to enter the engines intake compared to the FCR, this less restrictive path gives the fcr the snappier throttle response of the 2.

[WhiteZee]

thanks luke!

[jeepnrocks]

well it came today and im gonna put it on this weekend. i'll let you guys know what i think. it may just take some getting used to in order to be good for xc. i kinda thought the extra snap would be great for zipping and spinning around all the obstacles i encounter but then again the quad isnt exactly a slouch right now :)

[Stealth450r]

hey if you dont like i will take it off your hands. anyway let me know how it is .

[jeepnrocks]

haha thats why i wasnt afraid to get it. i figured if i didnt like it i could sale it very easily :)

[MY450R]

well? how is it jeep??

[jeepnrocks]

i wont have time to put it on till sunday :(