neonphil
Expert
Features of the FCR Carburetor:
Smooth bore for maximum air flow.
Flat slide with vacuum release plate for best throttle response and flow control.
Rollers on throttle valves and progressive linkage for smooth operation and control.
Equipped with acceleration without flat spots.
Designed for easy installations on popular motorcycles.
Easy jetting which can be done at track side.
http://www.keihin-us.com/fcr.htm
Holz Racing Products can not only take weight off an RX-1 Mtn. sled, but it can boost the ponies under the hood as well. HRP does this by using its new exhaust system, 41mm Keihin FCR flatslide carbs, K&N Filters w/outerwears; 13:1 J&E pistons and degreed cams. The clutching is a Polaris 800 RMK primary and Team Industries roller secondary.
http://www.snowest.com/news/news.cfm?ID=726
Smooth bore for maximum air flow.
Flat slide with vacuum release plate for best throttle response and flow control.
Rollers on throttle valves and progressive linkage for smooth operation and control.
Equipped with acceleration without flat spots.
Designed for easy installations on popular motorcycles.
Easy jetting which can be done at track side.
http://www.keihin-us.com/fcr.htm
Holz Racing Products can not only take weight off an RX-1 Mtn. sled, but it can boost the ponies under the hood as well. HRP does this by using its new exhaust system, 41mm Keihin FCR flatslide carbs, K&N Filters w/outerwears; 13:1 J&E pistons and degreed cams. The clutching is a Polaris 800 RMK primary and Team Industries roller secondary.
http://www.snowest.com/news/news.cfm?ID=726
Those carbs sure looks great but I think the yammieguys has developed the RX-1 carbs as most efficienent as they could be.
Is there any dynoshootouts?
Is there any dynoshootouts?
neonphil
Expert
Thay may be efficient but they sure are touchy and they're not easy to rejet.I had a problem this past season when I'm racing and the ice and hit a bump the sled seems to die or more accurately its stutters as if you hit the kill switch for split-second I am thinking it might be the vacuum slides closing when you hit a bump.
LazyBastard
TY 4 Stroke God
Sounds like you need the float bowl update.
neonphil
Expert
I thought that was just for the mountain sleds
LazyBastard
TY 4 Stroke God
Nah. Everybody has that problem. Mountain sleds just manifest the problem more due to running at extreme angles for greater portion of their time.
neonphil
Expert
Thanks LazyBastard I will definitely give them a try.
definitely cheaper than spenting $1800.00 carbs
definitely cheaper than spenting $1800.00 carbs
Silverbullet
TY 4 Stroke Junkie
$1800 bucks is almost half way to a new TURBO :!: :!:
I have 2 complete racks of R1 carbs that I never got to try last winter. 
neonphil
Expert
MXZ900 are the R1 carbs different form the RX-1 carbs?
40mm downdraft vs 37mm sidedraft.