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The D series Downdraft SU Carburettor

6th of November, 2019

The D type is an unusual downdraft style SU carb, usually mounting above the engine. The piston slides sideways so a piston spring is essential. The float bowl mounting is at 90 degrees to its usual position. The bellhousing is also different as well, with a small oil filler cap on the side. If the damper rod is removed, oil will escape from the piston tube and have to be refilled.

Many D style carbs have a slightly spotted/bubbling appearance to the main casting, as they get significant hotter through engine heat. Many D SU carbs met their demise from simply melting away on board an overheating engine on a hot day!

The D carbs are highly sought after, although only a few of the components are unique to this carb. The float bowl is the same as the H series SU Carb, as is the piston. Note that some SU Carbs have a small breather hole in the top of the damper rod, the D series SU Carb has to be fitted with a solid damper rod cap.

D SU Carbs

D2 SU Carb D3 SU Carb D4 SU Carb D5 SU Carb

More Information

If you have any photos or other information on SU Carburettors, I would love to hear from you. please send me a message: tim@carb.su


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