Does anybody have comparison result on dyno with stock cards and with FCR carbs ? Just need to compare what they worth.

From what I've seen on here (on a very highly tuned big bore nc30 engine!) they were worth about 5hp over the cv's.

Maybe more, maybe less depending on engine state of tune and fcr setup. Probably lots of dyno time needed if you don't know a good base setup to start with!

Ive never seen a 5hp gain, and I would suggest that has more to do with the Big bore kit exceeding the standard carb ability to flow fuel effectively. Without it you would see a lot less.

I've seen CBR's in a reasonable state of tune achieve 1hp or less with FCR's

I got 2bhp by just adding flatties and a whole day on the dyno.... a very expensive 2bhp. But its not about the bhp, its the drive-ability and the additional gearing options this gives on a CBR that makes all the difference. Col

yeurman wrote:I got 2bhp by just adding flatties and a whole day on the dyno.... a very expensive 2bhp. But its not about the bhp, its the drive-ability and the additional gearing options this gives on a CBR that makes all the difference. Col

One silly question - do they fit with stock airbox? Or with HRC airbox only ?

Nope, the standard air box wont fit, nor can it be adapted (as far as I'm aware), you need, and I wont say you need a HRC airbox, as there are copies out there that work just as good, but you do need to spend a few quid to get one that works well.... like my #1 bike in this pic, on the right hand side.
http://diddley.smugmug.com/Motorcycles/ ... 6424_iYPmM" onclick="window.open(this.href);return false;
Cheers
Col

Just try finding the correct offset inlet manifolds - let me know if you do.

GF have you looked at the CB750 (K I think) manifolds? They have an offset, but just not sure if it is the right one and haven't been able to get my hands on a set to look.

They also bolt to the head rather than clamp.

Has anyone ever tried making a custom throttle rod and centre spacers to use the standard manifolds?

Hi there
Done all this for a NC29 I built for the TT, Used std air box & the carbs went in to the std inlet manifold rubbers.If I find some photo`s I will post for you.

Pictures and some idea of what you had to change to use Std manifolds would be huge mate! !!