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I've been wondering

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Carb conversion Q

I keep hearing of people or wanting to do either twin 40/45 or bike carb conversions on their cars and thought of something which I've never seen done before.

After watching a friend put twin 45"s on his ABF'd mk1 and it never running 100% from that day I suggested bike throttle bodies as at the time I was breaking my R1 track bike and he explained about the agro of getting them set up.

Why when people are doing bike carb conversions do they only ever use banks of 4 from 4 cylinder bikes?

The manifolds have to be custom made so why hasn't anyone used a pair of carbs/throttle bodies from a twin cylinder bike I.e Ducati or Aprilias?

Would mean half the amount of testing and half the jetting and setting up

Am I talking pony or does this make sense?

Current rides:

2003 BMW 330d Manual Saloon Msport
1985 GTI cabriolet black edition (42k miles)
1999 Triumph Daytona 955i Post apocalyptic, rat, brat, scrambler, steam punk, cafe racer

IMG_20190803_123357.jpg

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So a total of 2 carbs?

Are they twin barrel carbs or single barrel carbs? If single barrel then one carb would feed two cylinders?

Similar in idea to one Weber DCOE feeding a mini engine? That was a common mod back in the day.

that used to be done due to cost of hardware as much as anything else I believe.

As regards jetting costs, you're right it would be cheaper although with bike carbs they tend to be drilled out so not too much of a saving. I believe it's the balancing that takes the time and effort.

Interesting idea

Ian

Cornish Host.
1980 VW Derby
Clive the Cabby
Ujum the Invisible
Mynx the  Tintop

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No minis had one 2 barrel carb because 5 port head, 3 exhaust and 2 inlet, unless you had the Arden 8 port head

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abfmk1 said

No minis had one 2 barrel carb because 5 port head, 3 exhaust and 2 inlet, unless you had the Arden 8 port head

Weber DCOE in a Mark 1 Mini? - YouTube

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borednow said

So a total of 2 carbs?

Are they twin barrel carbs or single barrel carbs? If single barrel then one carb would feed two cylinders?


Yep single barrel so would almost need the manifolds to fit 2 x 2 into 1

It wouldnt work on a DX due to the lack of space with the bulkhead but KR and ABF's would.

These carbs from twin cylinder bikes may also be easier to rejet rather than drill out to suit as twins need more delicate tuning when add things such as race cans and high flow filters because they tend to "hunt" in idle otherwise

Current rides:

2003 BMW 330d Manual Saloon Msport
1985 GTI cabriolet black edition (42k miles)
1999 Triumph Daytona 955i Post apocalyptic, rat, brat, scrambler, steam punk, cafe racer

IMG_20190803_123357.jpg
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