Advancing the secondary barrel on an ea82 carb

jims · Post by **jims** » Wed Dec 19, 2012 8:48 pm

Hi guys,

I was looking at an old ea82 carb today and began to wonder if anyone has come up with a good way to advance the point when the second barrel opens. As it stands I have to give it quite a bit for the secondary to open. It was thinking if I could get it to open lower in the rev range it might give me some more useable power.

One method would be to physically connect the two linkage points (with some wire or something) so that as soon as the first starts to open, the second moves with it.

Has anyone else found a good way to do this? Is it a bad idea? A good idea? Your thoughts would be appreciated.

James.

Post by **TOONGA** » Wed Dec 19, 2012 9:11 pm

like this?

http://offroadingsubarus.com/2bbl_hitac ... r_mod.html

it says ea81 but you can do the same mod to the ea82 carby.

TOONGA

tambox · Post by **tambox** » Wed Dec 19, 2012 9:22 pm

Make sure you read the additional information at the bottom of that link.
Carbies are a balance of air flow vs fuel flow.
If you open both venturies when the air flow is to low, you get a flat spot.
You can slightly improve things by adjusting the float level.
But if you want fuel efficiency, (look at the price), have it dynoed, but thats not cheap.
After you do new, plugs, check leads, check dizzy, filters, timing etc.

The novelty of what feels like more power when driven hard, will soon wear off once you see the fuel bill.

steptoe · Post by **steptoe** » Wed Dec 19, 2012 9:31 pm

I went to nut and bolt specialty joint and bought a pair of allen head bolts that just fitted through the slot 1/8" bolts (if you can call something that scrawny - a bolt) and pair of nylocs to go with them. Ran nicely on my twins, also had to zip tie the links for the air valve flap above throttle to keep it open on the secondaries

jims · Post by **jims** » Wed Dec 19, 2012 9:50 pm

Right, thanks guys.

Excessive fuel consumption is not something I'm too keen on. How did it effect your fuel use Steptoe?

steptoe · Post by **steptoe** » Wed Dec 19, 2012 9:59 pm

nah, gave more squirt (in my head), so able to shift up gear faster than hold a longer rev pattern

jims · Post by **jims** » Wed Dec 19, 2012 10:12 pm

Did zie tying the air valve flap open mean you didn't experience the flat spot Steptoe?

steptoe · Post by **steptoe** » Thu Dec 20, 2012 6:24 am

that may well be the reason why I had no flat spot ..... and depends why the flat spot occured. If it was due to dumping too much fuel to be able to atomise immediately .... I ran wetrol for sometime before converting to LPG which never goes in wet - it is already nicely atomised by the time it gets to the manifold

tambox · Post by **tambox** » Thu Dec 20, 2012 6:37 am

If you change your driving style, ie dont drive it like a normal car, and work with the venturies working at the same time, you will get quicker "response" in some situautions (3000 + rpm).
But you will loose (flatspot) when you put you foot down at low RPM. This will make you inclined to rev it as it feels better, this uses more fuel.
The only way to find out if it suits what you want, do it, its easy, and you can easily undo it if you don't like.

steptoe · Post by **steptoe** » Thu Dec 20, 2012 6:39 am

well said

jims · Post by **jims** » Thu Dec 20, 2012 11:02 am

Yeah thanks Tambox and Steptoe. I will try it out today and let you know how I go

cheers

jims · Post by **jims** » Thu Dec 20, 2012 1:43 pm

So I got this done today. Instead of a bolt and nut I used a small cut down spring between the two parts.

There is a very noticeable difference in power. First and second especially. Revs much quicker and gets going like it never has before.

Having said that it is idling rougher...

I will drive it around for the next few days like this and keep an eye on the fuel use. Then I will either keep it there or rip it out.

Thanks for the advice!

Jams