Can someone explain the difference in the carbs.

[n2deer]

Between a the fcr carbs and why they get better throttle response versus the carbs on the 04-05 450r bikes thanks

[chad502ex]

Originally posted by n2deer
Between a the fcr carbs and why they get better throttle response versus the carbs on the 04-05 450r bikes thanks

night and day throttle response, and a taper bore FCR will add another 2-3hp from off idle to rev limit..

[n2deer]

Thanks for the reply, but what are the mechanical differences that causes the better throttle response.

[chad502ex]

better fuel/air metering circuits, slide vs, butterfly..

[GPracer2500]

Here's the slide: The FCR's slide rides on rollers. There are more rollers where the linkage engages the slide. Pictured on the right is the FCR slide's vaccum release plate. I'm not entirely sure how it functions.

http://k41.pbase.com/u39/jdjetting1/large/25566126.Im000245.jpg

This diagram shows a view of the slide as if we're looking at it from the top.

http://www.keihin-us.com/am/_media/images/products/fcr/throttle-valve-top01.gif


The 04/05 450r carb uses a round piston valve slide and a butterfly.

[n2deer]

Now we are getting to the meat of the subject. thanks alot for all the replies.
Any more info that can be had on this subject.

[n2deer]

Are there any posts around here about what it takes it put a yfz 39mm fcr on the 04-05 trx.