8 replies to this topic

[jim4eva]

Hi,
I'm interested to know what the advantages of having R1 carbs on a 998 are. I've found a similar post which was not especially helpful as everyone just slated them and said "whats the point on a 998". So, what are the pros and cons? I've heard that they are more efficient? Any other information would be very much appreciated!
thanks!

[jaydee]

Not an expert on bike carbs but R1 carbs are the modern equivalent of SU carbs, but form memory they're 38mm so basically a twin setup will be like having twin HS4, so unless you have a very good cylinder head and an upgraded camshaft, they're too big hence some said they're useless.

[jim4eva]

....so unless I had a high spec 998 it would be advisable to either keep the su I have, or use smaller bike carbs?

[jakejakejake1]

People generally say they are not worth the hassle as on most A series engines the carbs are not usually the restriction, usually a better exhaust/inlet set up, a better head and different cam will be needed before the carb becomes a restriction. Thus there is little point in upgrading to them for most people.

[Bradley Gaunt]

The bike carbs should atomise the fuel better so probably will improve mpg. I believe they also have 2 needle profiles so you can get optimum power and efficiency throughout the rev range. They are 40mm though and therefore may be too large for a 998... They require a bespoke inlet manifold fabricating and also the choke and throttle linkages extending and of course rolling road tuned to jet them correctly. Call the bogg brothers they should be able to advise.

[jim4eva]

Thanks very much for your advice, very much appreciated.

[minimanjay]

I run twin 32mm Kawasaki carbs on my 998 with a 12g295 head lcb and a custom ally manifold runs sweet sounds better and torque is amazing !

[Udo]

The bike carbs should atomise the fuel better so probably will improve mpg. I believe they also have 2 needle profiles so you can get optimum power and efficiency throughout the rev range. They are 40mm though and therefore may be too large for a 998... They require a bespoke inlet manifold fabricating and also the choke and throttle linkages extending and of course rolling road tuned to jet them correctly. Call the bogg brothers they should be able to advise.

Exactly what I found ^^^^^^^ better MPG, more torque and same power as a weber DCOE45 but at 1000rpm less, see link in signature below. This was on a 1293 but should give an idea of the work involved

[jaydee]

I run twin 32mm Kawasaki carbs on my 998 with a 12g295 head lcb and a custom ally manifold runs sweet sounds better and torque is amazing !

That sounds reasonable as twin Hs2 are 32mm.