Classic Mini Twin HS2 SU Carbs Speedwell Conversion Completely Reconditioned

We had the pleasure recently of being given the job of restoring beauty and function to this original Speedwell set of Twin HS2 SU carbs which were fitted to a 1962 Mini Traveller.

As you can see, they were extremely heavily corroded and most of the moving parts were seized.

We had to fully strip them, which was problematic as the throttle shafts were seized in the carb bodies so they had to be removed in pieces. It was at this point that we noticed that one of the throttle shafts was extended to be able to accommodate the flexible coupling which connects the 2 carbs together. These are not a left and right handed set as you would usually find on cars of this era, rather they were the same orientation. The throttle shaft on this carb model usually finishes flush with the body on the side of the float chamber.

Usually this would not present a problem as the carbs are usually joined on the side of the linkage. To enable the fitment of the flexible coupling, given that extended shafts are no longer available it was necessary to carefully drill and extend the new throttle shaft, using a small section of the original shaft.

Typically with twin SU carbs, the manifold is cast in one piece, with the spacing set to enable fitment to A Series heads. Speedwell made their manifolds in 2 separate pieces, joined only by a rubber balance pipe.

We had to mount the 2 assemblies to one of our stock Mini heads, so that we could set up the interconnecting linkage at the correct spacing.

To clean the carb bodies and other pieces, we firstly ran them in a hot ultrasonic bath to remove all grease and oil deposits, and then carefully vapour blasted them to remove the aluminium oxide corrosion. The owner had started to clean the float chambers and manifolds using a wire brush which had left them scratched, so these items were then buffed using a sisal wheel on a bench grinder.

 The carbs were set to factory mixture and idle settings, ready for our client to refit to the vehicle. Lets hope they last another 56 years!

The parts used in this job were 2x genuine CRK 104 SU Rebuild kits. We can supply these if you wish to undertake this work yourself, or if you are interested in having your own SU carbs reconditioned, of any type, please get in touch using the contact form below.

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