Laguna Seca Race Carb or OEM?

[Charlie]

I have 2 sets of carbs for my Laguna Seca.

OEM and race.

Both Dellorto. OEM is PHM40, race is PHM4D

What does the race give me? Is it really very much better?

I am reluctant to use it because it does not have an acceleration pump, or an idle speed adjustment screw.

I would guess that Idle speed adjustment on the race would have to be set using the throttle cables, 'cause the slide is completely closed with no tension on the cable. No way the engines gonna run with the slide completely closed!

And, the race has no acceleration pump!!???

Both have idle mixture screws.

The race throttle slide is about a mm larger in diameter (even tho the nomenclature would indicate both are 40 mm carbs). That doesn't seem like a big deal. Also the race has a tickler instead of a choke.

Surprisingly, the race has smaller jets; its needle is one step richer however:
Race main 142
Race idle 65
Race needle K4

OEM main 145
OEM idle 75
OEM needle = K5

{BTW, I have another active post about jetting for altitude}

Charlie

[Eldert]

Hi Charlie

are they racecarb slides differend in color ? kind off dark grey ?

if so the slides are hard anodized and the carbs are reworked Dell Orto s by Malossi and the diameter could 41,5 mm and some are even 42,5 mm

these carbs are worth a small fortune

Eldert

[Charlie]

Yeah, they are the anodized slides.

And yeah, they are probably 41.5 mm dia.

Picked them up from the guy I bought the LS from for $100.

At this point, based on the type of riding I do, I don't plan on installing them on the bike.

For me, its the lack of an idle screw and an accelerator pump. Perhaps no idle screw for a race bike may be an automatic on/off switch in case of a crash!

Charlie

[Eldert]

Hi Charlie

there is a forum out there dedicated for bikes like yours

http://www.ducatittandf1.com/

Eldert

[Ray O'Donohue]

I am always surprised and a bit skeptical of the "no idle (throttle stop) screws concept on a race bike. When I backed the idles off to nothing on my racer,the results were terrible on a closed throttle. It went into corners better with the throttel stops screws in place,and in fact providing a fast (if lumpy)idle.