Cam work is the usual next step after airbox, exhaust/header, mixture, and balance on a dual Keihin D-series that will stay carbureted. A freer cam only helps if the engine can fill the cylinders and the carbs still supply the fuel - otherwise the car just goes lean or peaky.

Important

Fit breathing and fueling first (service, airbox or properly jetted stacks, free-flow exhaust, mixture/balance, wideband). A cam on a dirty dual-carb D14 is an expensive way to learn that lesson.

Why cam the dual-carb D14 / D15?#

Stock dual-carb D14A1 cars are economy-oriented. Community dual-carb street builds that advertise serious wheel figures almost always list a cam package with the rest of the bolt-ons. Documented dual-carb GL / D14 packages include roughly 116 bhp (Bisimoto stage-1 style cam, stock airbox, ~1.75 in exhaust), ~122 whp, and signature notes around ~127 whp @ ~6200 rpm on fuller builds (not cam-only).

OEM lobe sizes (community caliper measurements)#

Forum non-VTEC SOHC lobe base diameter and lift notes (measure your own cam; treat as comparative, not factory print):

That is why a D15B cam is the usual first step: a real but modest lift increase without a full regrind.

Option 1: OEM D15 dual-carb cam in a D14 (mild)#

What people report#

• A D15B cam is a straightforward lift bump over stock D14 (see table above).
• The rocker assembly is the same family as the D14 dual-carb head; some owners fit the complete rocker assembly with the cam.
• At least one dual-carb GL diary notes fitting a D15 cam by careful timing-belt work without a full strip.
• D15B / D15A1 cams show up in EG Civics, Concertos, and related scrapyard SOHC non-VTEC heads.
• For dual-carb engines that still use a mechanical fuel pump, use a cam that retains the fuel-pump lobe - community consensus is D15B non-VTEC and D16Z1 are the usual safe donors; many other SOHC cams omit that lobe.
• Idle and cold-start problems after a D15B swap are not automatic. Several dual-carb GLs report no idle/startup issues when clearances and timing are set; the biggest seat-of-pants change is often a sharper exhaust note, with power gains muted if the exhaust is still restrictive.
• Gains show up more after free-flow exhaust and mixture work - the cam alone on a stock cast manifold is easy to under-appreciate.

Tip

“Even a D15 cam in a D14 helps” is a recurring community summary when discussing still-carbureted bottom ends, including when comparing mini-me / head options.

Checklist#

1. Confirm cam and rockers are for the correct SOHC dual-carb head family (do not mix random VTEC rockers without a full plan).
2. Set valve clearances cold after install (FSM procedure and values for the head you have).
3. Align timing belt marks carefully; dual-carb SOHC is less forgiving of a tooth out than it feels.
4. Re-set base ignition timing, then mixture/balance. More cam usually wants more fuel at higher rpm.
5. Road-test for valve noise, ping, and flat spots; log AFR if possible.

When it is enough#

Use the D15 OEM cam when you want a cheap, reversible step after exhaust and airbox, without paying for a regrind. Expect response and midrange, not a night-and-day top-end on a stock D14 bottom end.

Option 2: OEM D16Z1 cam (next step after D15B)#

• D16Z1 lobes measure larger again than D15B (table above).
• Often found in Concerto engines in UK scrapyards.
• Fewer dual-carb GLs actually run one than talk about it; owners who do usually keep dual carbs and add breathing + exhaust.
• An adjustable cam pulley is sometimes discussed when swapping across D-series SOHC cams so you can re-time after the change.

Option 3: Aftermarket regrind (e.g. Bisimoto / Newman-type)#

What the dual-carb community uses them for#

• Bisimoto and UK regrind shops (e.g. Newman quoted around £200 on a stock D14 blank in one thread) are the usual answer when someone wants a dual-carb D14 that pulls harder high in the rev range (including “toward 8k” wish-list posts).
• Some Bisimoto stage-1 profiles are described as relatively mild; still enough, with a free exhaust and sorted airbox, to land around 115+ bhp on a dual-carb GL in community reports.
• One dual-carb D14 Bisimoto diary discusses power moving up the rev range, with peak torque around ~5300 rpm on that package (trade some low-end plumpness for higher-rpm work).
• Owners often send a D15B core to the regrinder rather than a worn D14 blank.
• Builds that publish ~122 whp or ~127 whp @ ~6200 with dual carbs + Bisimoto also run the rest of the package (exhaust, induction, tune). Do not expect stock carbs and a cam alone to match those figures.

Supporting work after a regrind#

Warning

Asking a dual-carb D14 to live at high rpm with stock springs, stock jets, and a hot grind is how you get valve float, lean holes, or melted pistons. Stage the supporting mods.

Option 4: Other paths (context)#

Dual-carb VTEC mini-me package dyno near 119 hp - cam/head work class, not a mild OEM cam alone (Gizmo).

Always measure a used cam (base diameter and lift) and confirm against the grind card or FSM rather than trusting casting marks alone.

What a cam will not fix#

• Dirty or unbalanced dual carbs
• Heat-soaked open stacks with no jetting
• Stock cast manifold into a crushed exhaust
• Detonation from too much advance on low octane
• Expectation of B-series power from 1.4 dual carbs

Community dual-carb tuning guides put cams in the same “real power” list as jets, needles, and timing: after the free breathing work.

Suggested order (still carbureted)#

1. Service + carb rebuild, mixture, balance
2. Airbox flap/heat delete + panel filter (or stacks with fuel work)
3. Free-flow exhaust + 4-2-1 header
4. Mild timing advance under load
5. D15 OEM cam or mild regrind
6. Re-jet / needle as AFR demands
7. Only then: more aggressive grind, head work, or dual-carb VTEC mini-me

Related articles#

• Street Tuning Dual-Carburetor Honda D-Series Engines0
• Setting Idle Mixture and Balancing Dual Carbs on a D14A10
• Dual-Carb Intake Options: Stock Airbox versus Velocity Stacks0
• D14 Dual-Carb Exhaust Manifold Selection0

Safety and reliability#

Caution

Always confirm TDC and belt marks. A jumped belt or wrong cam gear index can bend valves on interference D-series engines.

Note

Verify any grind card and clearances against the cam supplier and the Honda factory service manual before assembly.