Topic: BMW E21 Keihin

[Wilmo]

Hej all,

... And now time for something completely different. Sorry for having too much wheels, I have got an BMW E21 with an M10 motor with 1800cc. It is of course not a new car anymore and therefore it needs to be fun to drive it. My current Pierburg with a 25mm venturi is not a lot and therefore I am thinking of building in a Keihin from a Honda CB. And I need some help there.

I found a Keihin VB online: http://www.marktplaats.nl/a/motoren/onderdelen-honda/m876844534-honda-cb-carburateurs-keihin.html
Don't worry about the choking language, no info there. Only nice pictures.

I wonder how the choke works, is it manual? How does this one look? I wonder where the connections at the bottom are for. Is it for a back feed of petrol? Or is it vacuum?

Could you help me as well with finding the right jets? Or should I better forgot the whole project?

Greetings,

Wilmo

[Bankerdanny]

Those are CV style carbs and use a butterfly actuated by a cable.

I think that you would be far better served to use one of the readily available Weber conversion kits for your car. Jets are easier to get and change, you won't have to attempt to fab up an intake, and there is a large community of E21 owners that will be able to give you proper tuning advice.

[scottly]

1+ for Webers, specifically a pair of 40 DCOEs, as were used on the BMW/Alpina.

[Bankerdanny]

There are several motorcycle carb based setups available for British cars, Triumphs and MG's, and if you could find one of those that might be an option. But unless you have really strong fabrication and tuning skills doing it yourself will be a major challenge.

[jas67]

1+ for Webers, specifically a pair of 40 DCOEs, as were used on the BMW/Alpina.

For the 40 DCOE's, you'll need a cam, some headwork, and a matching exhaust to go with it.

There are also some 38mm side drafts available that are less radical, and could yield better results with a closer to stock engine.

You'll definitely want to consult with some BMW car forums before spending money on this one.

Are you a BMW CCA Member?   There are some forums on the BMW CCA website.