A bit off topic, but a biker friend is talking up Keihin FCR carbs as a good modern replacement for SU or Weber DCOE carbs. Apparently there are plenty of modern innovations on them that make them outstanding on bikes and he's pretty sure they'd do a bangup job on CEC applications as well.

I'm trying to figure out sizing equivalencies, ie 39mm FCR = 44mm SU or pair of 41mm FCR = 45DCOE. I'm assuming with the slide plate throttle they'll flow substantially more than an equivalent butterfly carb but I'm not sure how much.

PS, I thought this might be better suited to the engines page but figured there would be more expertise here.

TIA, Ted

Apart from having one fitted to my Harley, and that it works just fine, no other knowledge, sorry, Cheers Ray

http://www.keihin-us.com/slide.htm

i use them on my jetskis

and also this

http://www.keihin-us.com/fcr.htm

We used to use them on our F1 and F2 sidecars - the FCR flatslides have screw in throats that push into the engagement rubbers on the heads so within reason you can screw in smaller ones. On our F1 we ran with 41mm's throated down to 39mm and I believe they do a vast range of sizes so if you buy bigger you can always sleeve down.
Allens performance on the internet are the official UK importers and really helpful.
They are expensive new but I do have a customer who is selling a set 2nd hand if thats any good to you
They also have a completely different feel to them and as you are operating the slides direct rather than through vacuum, you have to adopt a squeeze and then nail it technique with them, If you want any more details give me a call on 01449 736633
Oh and they are worth having for the noise alone!!!
regards
Andy

Thanks Andy

I'm looking at something like this setup:

(FCR Horizontal Double)

as an alternative to a 45 DCOE on the Mini rally car.

I can pick up a pair (two singles actually) of FCR MX carbs in either 39mm or 41mm for about £25 a pair. I'd need to gather up some hardware and linkages to convert them to a "proper" pair. Or failing that, source a linked pair.

I'm mostly trying to figure out if they're tunable to be useful on an automotive engine or if they're only really suitable for the highly developed motorcycle and jet-ski engines they tend to live on. Hearing that they work in the semi-agricultural Harley Davidson world is encouraging.

Cheers, Ted

[Edited on 7/8/09 by andkilde]

Get yourself a set of zx6r j or g model carbs and ring bogg bros and they will make a manifold to fit them straight on they come with a tps allready fitted and generally are a good replacement for 45s
i am fitting some on my 2 litre zetec
what engine are you running??

FCRs every time! They should work fine on a Mini - may take a bit of setting up but will be excellent once sorted!

You're probably not far off with your sizing, maybe even a tad conservative!