Max. tilt on Keihin FCR MX carburetor

Does someone know how far forward or backward I can tilt a Keihin FCR MX carb? When will it affect performance?

Thanks! :smirk:

Pretty far. You may have to change float height to deal with extreme angle, say over 30 degrees. Jetting too, may change at extreme angles. I assume the FCR is not going on a dirtbike?

Ok, interesting. The FCR's (2) are meant to be mounted on a BMW 1000. Due to space restrictions they might have to be tilted.

Can you indicate on how the float leven should be changed (lower, higher) according to tilt? I suppose there's no difference between forward and backward tilt?

LOL, no specs I know of that are based on degrees of tilt for float height.

I would install them, see if there is any fuel seepage. Be sure to check inside the carb bore too. If none, I jet it and ride. If you notice jetting issues say on corners or under braking or acceleration, you may have to change the float height. If you lower it, you will probably have to richen the pilot. Needle and main will be fine over a wide range.

This being done to an airhead i assume? If so, I cannot imagine the angle will be that extreme.

Ok, haha.

Airhead, yes. The FCR's are higher than the current carbs, and block the area for the shifter and foot. Tilting them might solve that problem.

Any reason you do not do the standard Mikuni round slide conversion? As I reacall, they fit like a dream.

I doubt the AP and the flat slide are going to make much of a difference to one of those engines.

I'm not sure. I'd have to ask the owner of the bike.

I will Google for info on that conversion, thanks!

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