Is this some kind of restriction kit or is this how they leave the factory

That looks like a restrictor

Full fat FCRs should either have airbox adapters or bellmouths fitted-

https://www.google.co.uk/search?q=fcr33 ... 66&bih=643

Looks like they can be unscrewed though.

During the later stages of the 400's there was a factory agreement that stock bikes wouldn't exceed a certain BHP, it's why the NC35 puts out lower bhp than the NC30. A similar thing would have happened to the FZR but as it was only affecting new bikes it would have gone onto the SP with flatslides .... could be Yam's way around it.

They can be unbolted yes which leads me to think they maybe yams way round of getting them to work with a airbox, and full bore stubs are/were available to buy.

Kayla, sorry i should have mentioned that pic is of the engine side of the carbs not the airbox side

Well i have from one source that this is how the FCR's in road trim are which makes sense.

Does anyone else here run FCR's on a road 3TJ?

I'll swap your 'slow' carbs for a set of much faster SP ones

lol so you have a set with the full bore stubs?

My bad, I ment Mikuni SP carbs

lol na your ok i have a set of them

In 1993 the japanese bhp limit for 400cc bikes dropped from the previous 59bhp to 53bhp.

The RC sugo race kit would have included some parts without that restriction. Can it not be milled or turned away on a lathe?

Dan