OEM Carb Mods While You Are Saving For FCR Flatslides.

[koko64]

 

I am interested in the process and may try it on a spare set of carbs.

[koko64]

Any progress?

[scaudill]

Sorry about my delay posting. 
Set the floats back to the original setting.  Dropped back to #40 pilot jets.  Todays ride was good, not perfect, bike is fun to ride.
I'm going to ride this set up a few days. May need to go back to #37.5 pilot and drop needles a little.
There is so much info about float setting.  The right side float measures about 2.5 mm higher than the left because of the shape.
I set the left side at 11 mm, right side float was 13.5 mm.  I'm talking about one carb float, left side and right side.
Maybe this is common knowledge, but I've learned a lot more about these carbs.
My friend that lives in NW PA reminded me we have a ride in Lewistown, PA in May.  He rides a 900SS bevel that he bought new it is a beautiful bike.
thanks,  Sterling

[koko64]

Yeah the two float halves in each bowl are not symmetrical. You measure off the squarish one rather than the romboidish shaped one in each bowl. Its 14mm off the squarish float half. One of the float halves is trickier to measure on the inside position. Going off the wrong float half throws out your setting big time. The float has to be only half bottomed out because the needle has an internal spring. A 45 or less degree angle of the carbs not quite upside down gets you the correct drop of the float. Its easy to stuff it up if you dont know the little nuances of these carbs.

[ducpainter]

Just got off the phone with Eric. Flatslides have risen in price significantly for this year. Sudco is saying the price will be $1400 with no availability until July.

Start saving nickles and dimes along with those pennies.

[koko64]

Ok everyone, and just so you know I'm not getting anything outa saying this, but snap up the FCR carb kits from Motowheels and California Cycleworks while they have stock. Prices are under a grand USD for the 41s and under $900 for the 39s, so you save yourself 500-600 bucks. If I had the cash I'd buy a dozen sets, but nearly all of my few Ducati customers already have them.
They are sponsors so I'm happy to plug these guys and give you the heads up. I think the oem carbs were a real bad choice for these motors bar the enrich/"choke" circuit.

[koko64]

Upon investigation the FCRs are getting scarce, so I guess I better start modifying Mikuni CV carbs and putting them aside. 
The lack of response of the oem carbs is really apparent after you have tried FCRs. Some of the mods in this thread help noticeably, but you just cant emulate the immediacy of response you get with well set up flatslides.

[scaudill]

BSST 38 question.
  I've been having trouble with the idle.  Seems like the throttle stop screw is much further in than I remember. How far open should the throttle plates be?  These are open 2 to 3mm. 
Sterling

[koko64]

What kind of trouble?

[scaudill]

Doesn't want to idle, I continue turning the idle screw in but after a ride its too low again.  I'm going out for a short ride now.  Report back later.  

The ride didn't happen.  Wind came up with some rain.  I'm thinking the idle circuit must be plugged or something.

[koko64]

Hows it going?

[koko64]

After a bit of playing with components, here's a thought; you can add a quick turn throttle to carb mods for the soft acting BDST38s. Unlike flatslide carbs, the carbs are forgiving to the point of being boring.

Motion Pro, Domino and Mikuni all have single cable, quick turn throttles and some come with different cams to tune the action. While FCRs can be abrupt and nowdays come with a gentler initial throttle action, the BDST 38s require a long pull and have a slow action. Being butterfly carbs, a single cable throttle will work fine if correctly set up in contrast to slide carbs which need a push/pull throttle or heavy return springs for safety. I consider a single cable for ease of installation and a clean action. The irony of push pull throttles is that if set up incorrectly they can cause your throttle to jam open! Otherwise they can return poorly and be unsafe with very high idle speeds from not returning correctly. Caveat: Any carb can jam open if set up and adjusted incorrectly.
A quick turn throttle will therefore help the impression of throttle response on the softly responding CV carbs.
I am going to test a Mikuni Quick Turn CR Pro Comp throttle I have ordered from our Mikuni importer. It appears to be made by Motion Pro for Mikuni. Will let you know how it goes.

[scaudill]

Last few days I been riding not tuning the carbs.  One of my problems was the small spring that goes between the sync lever and throttle lever was missing.  I think it fell out while reinstalling the throttle cables
Now I have the mixture screws out 4 1/2 turns.  Idle is good and bike pulls strong.  The problem I'm having now is at low rpms (2000-3500) there is some surging.  Really not bad.  The warmer weather helps.
I now have 40 pilots installed, since the mixture screws are so far maybe I should go up to 42.5. 
The needles (one notch only) has the stock washer under the clip.
Sterling

[koko64]

Needles stock or aftermarket? Do they taper to a point? One notch from top or bottom?

[ducpainter]

I read it as the needles only have one notch. That would make them stock....no?