1216 and HEAD WORK, CARB SIZING??

[JIMMYLEWRENCH]

Good Day Everyone,

My engine will be running a 1216 with over sized valves.  I have acquired a set of Keihin 41FCRs.  I do not have experience with these carbs.  I'm sure these will flow enough.

Questions,

What benefit would there be in running a smaller sized set of carbs?

Thanks, any info passed on would be great.

[Gixer1460]

The 41's will certainly work on a 1216 but will be very top endy. But for a road bike 36mm RS flatties might lose 10 - 15hp overall but the midrange will be stonking which is where most use tends to occur!

[dupersunc]

Those FCR41s are way too big.  The bike will be unrideable...

Sell them to me.

[wraith]

2 minutes ago, dupersunc said:

Those FCR41s are way too big.  The bike will be unrideable...

Sell them to me.

[Solcambs]

The 41s will be good for top end ... but IMHO will be a bugger to ride everyday at normal rpm ... My 1216 runs FCR39s ... flowed head, standard valves GSXR1100M motor. 70ftlbs at 3.5krpm climbing to 90 ftlbs at 6Krpm and 147-150hp (clutch slip at the time)

• + 4 degrees additional advance
• 106, 110 cam timing (or was it 105, 109?)
• dyna 2000 position 2,
• 10K rpm limit

Carbs FCR39

• 55 pilots
• 160 main jets
• EMP jet needles (clip @4)
• 200 main air jets
• 100 pilot air jets (1 turn out).

[Foz]

Rs 38’s and 36’s both worked well on my bandit however for day to day use and making it more user friendly I reverted back to the cv’s with a modded airbox. 

1216,big valve ported head , dialled in gsxr cams etc and it’s 148hp/95ftlbs , if I went back to the flatslides I may gain a couple of hp but it’d spoil the midrange. 

I was talking to Sps about fcr’s and he suggested 37’s would be best on a 1216