Laguna Seca Race Carb or OEM?
Posted: Wed Jun 29, 2011 10:18 am
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
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