[surffly]

Got a rough baseline to start with the needle positions?
Just wondering how many turns out to start with.

 

[MrSprinkle]

Got a rough baseline to start with the needle positions?
Just wondering how many turns out to start with.

Consensus seems to be that baseline jetting it too rich while needles are to lean. I have a recent thread about my jetting woes with 39s (got it sorted eventually)

from that thread:

Here's where I ended up:
Slip ons, K&N pods with cut battery box
152 mains
55 pilots
1.5 turns mix screw
EMR needles / 3rd position

Here's where I started:
Slip ons, stock air box w/ K&N
155 mains (kit came with 160s but had swapped these a while ago)
60 pilots
Mix screw almost closed
EMT needles / 3rd position

 

[ducvet]

Can you let us know more details?
As Mrsprinkle has broken it down in his post the details matter.

Split or bank of carbs?
What needles?
air box or pods?
If airbox: closed or open lid?
Engine mods?
Exhaust?
Miles on motor (how fresh)?

Every engine is different so there will be variances. I should have a number of bikes with this setup so can let you know what I have run with success. This does NOT mean they will match your bike as mentioned I find variances when dyno tuning with all carbs and fuel injection on similar bikes. This would be to get you close.

 

[StraDuc]

Hey Eric welcome back! I missed your always insightful responses!

 

[surffly]

Split or bank of carbs? Bank
What needles? That I do not know
air box or pods? Stacks (blue)
If airbox: closed or open lid?
Engine mods? Should be stock. Bike is a Bimota DB4
Exhaust? Bimota Corse Ti
Miles on motor (how fresh)? 7k

Carbs came off for a cleaning. Thought I wrote down how many turns out the screws were, but cant find it now. Thought they were 1.5 and 1.75.

 

[ducvet]

I swapped a set of FCR39's onto a Db4 back around 2008 but I can not find any notes on what I used for it. It had the Corse kit and the customer convinced me to remove the 41 fcr's and reinstall the kit FCR's (39's) before I sold it. I will have to look through my photos to see what filters were on the carbs. I do know I have not found a reason to ever use the blue or red plastic stacks that come with FCR's .

The bimota exhaust is a 2-1 IIRC so that may make some differences compared to supersport setups I have so keep that in mind.


Mains 148-155
pilots 62-68
fuel screw 1/2 out
Air screws 1-1/2-2.0 out
Needles 3 to 5-1/2

Note all jets must be Keihin brand no mixing of "made just as good as " jets

These settings are used most often on supersports if the Bimbo is closer to a monster 900 expect to need larger mains such as 160-168's .
Also keep in mind these were all with a open airbox and panel air filter so if you plan on running stacks it will likely change. Also keep in mind if you attach any screen to the end of the stack you will wreck air flow with turbulence.

Good luck.

 

[surffly]

Yeah I was going to run the cone filters (with the proper mount), but wanted the sound of the stacks. Im sure there is no really good reason to run them.

The Corse exhaust is a 2-1