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General Tech SU versis Mikuni carbs

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tinman58

tinman58

Jedi Knight
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I was in the process of getting the new SU carbs from Moss when a friend with a TR 250 gave me some information about Mikuni carbs. I was wondering what kinda info anybody has on their use or knowledge of the Mikuni carb's.
https://www.v-performance.com/products/air_fuel.html
Any input would be apperciated.
The carbs are a Christmas gift for my Wife.
 
Have worked on Mikunis on boats and motorcycles works on them. Seen on some Datsuns.
 
I saw a Spitfire at Triumphest a few years ago. They looked cool and the owner reported improved performance but said gas mileage suffered. A lot.
 
Poolboy

thank you for the info.
I am going to order the mikuni's today.
 
I'm more of a bike guy, so I have experience with motorcycle carbs.

A flat slide (or even a cheaper round slide) will flow a lot more for a given throttle bore diameter than a SU. Carburetor circuits number about the same (certain ones are pumper types). The big difference is the needle is controlled by the gas pedal, not via vacuum (like a cv (SU) carb).

I'm not convinced they're better than a properly set-up DCOE Weber. The Webers have more circuits, and because of that, they're more tuneable. A very good tuner with a DCOE can get a flat fuel curve through most of the rpm range. Where a motorcycle carburetor will have the advantage to beat a Weber is to flow more air for a smaller diameter venturi... this increase velocity through the venturi which will improve the carburetor 'signal' and atomization.

That said, annular venturi DCOE Webers do exist, and would be the ultimate. Basically, this design removes the booster in the middle of the venturi, so you can use a smaller choke for a given cfm, which improves the carburetor signal and atomization - which keeps things flowing up high but provides better velocity and 'signal' at lesser engine speeds. It's a win-win.

Hope this helps.
 
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