Keihen FCR41 carbs.

[Goofle]

There's a pair of the above carbs on Facebook at present. Just a curiosity what's the advantages of fitting the? More power? Smoother delivery? Or simply an increase in power to weight ratio as your wallet would be significantly emptier?
This is a purely academic question by the way. I'm just curious and would need massive improvements to justify the price....

[Zimbo]

You won't see much benefit in terms of power gain over the standard carbs, but the way the bike "feels" is very different, in particular the throttle response is absolutely immediate and the bike is much nicer to ride. Also, fuel consumption is improved by around 20%, so if you do many miles the carbs will over time pay for themselves! Best fitted with race cans and an open airbox, and the fueling checked on a dyno.

[Dukedesmo]

The only downside is that they have no 'choke' so cold running can be tricky.

I have them on mine, although mine are single carbs on short intakes and, I assume you are looking at a banked pair? (if not then be aware fitting split singles is far from straightforward) and starting from cold is OK as you give them a couple of 'squirts' of fuel from the accelerator pumps but it will run rough until it's warmed up which is Ok for me as I only use my bike in warmer weather, but if you ride it year round then maybe not such a good idea unless you want a 5-10 minute warm-up session everyday in the winter!

On the plus side the throttle response is instant as no relying on vaccum but they come into their own when combined with other mods; big-bore, high-comp, cams, gasflow etc. - I have all these on mine and it out 'grunts' my 916 (which makes 30hp more) up to 6,000 rpm...


PS; I can't really comment on fuel consumption as mine only does around 36mpg but this is due to many things, not just the carbs.

[Dirty]

What do they want for them on FB? They are available new on fleabay for somewhere between £500 and £700 (depending on if anyone is bidding) http://www.ebay.co.uk/itm/Keihin-FCR...item1c53776b54

One small thing to add to all the top advice above. Replacing the airbox with K&N pods, though possible with the standard Mikuni carbs they were designed to work with the airbox. The Keihens were designed for pod filters.

[Saint aka ML]

For fast idle option buy a 916/748 throttle tube that has a button that removes slack from throttle cable raising idle speed till you touch the throttle.


Handy.

for cold running I been running them in winter in as low as -8. Not perfect but way better then stock. Frankly stock needed additives to petrol for carb icing at about 7 and below (depending from humidity).

FCR's from about 1 and were rid able till about -2 until you had to add something to petrol.

[Goofle]

Nottsbiker, pm sent!

Many thanks!

Now bidding on the ebay set - bonus payment from work come exactly at the right time!