I know a lot of people aren't interested in playing around with the stock K series Aisan carburettor. I reckon they're tops and if it wasn't for the ridiculous cost of a rebuild kit and a dip in the acid bath, i'd spend my days rebuilding these little gems.

 

I've handled a quite a few 3k and 4k variants but i'm looking for any information on jet sizing in regards to the 5k version.

 

I know there are variations between each and every carb but sizing on the idle, mains and power jet would be great.

 

Below are my ke70 4k and ke30 3k carbs.

Edited March 26, 201412 yr by GJM85

Just looking at tuning my twin aisan's on Saturday (stock set now fitted to 5K with very lumpy cam). You know anything about the butterfly and float settings... is there any adjustment on these?

Float setting is 6mm and 50mm. Carb top to float top and car top to to float bottom.

Base setting for idle mixture is 2 turns out from seat and idle speed screw is 1&1/2 in.

 

Not sure how that 3k twins run on a5k with standard jetting considering I can't get a standard 4k unit to run right with standard jetting on my 5k.

 

I'll say though that the early ke2# series single carbs did come out with some larger jetting than the later 4k carbs

Thanks Gavin, I'll pass this info on to my mate who's going to be tuning the thing on Sunday. I'll let you know how we go!

Pretty sure I have a standard 5k carby in pieces in the shed somewhere, i'll post a pic if I remember later,

 

cheers!

Float setting is 6mm and 50mm. Carb top to float top and car top to to float bottom.

Base setting for idle mixture is 2 turns out from seat and idle speed screw is 1&1/2 in.

 

Not sure how that 3k twins run on a5k with standard jetting considering I can't get a standard 4k unit to run right with standard jetting on my 5k.

 

I'll say though that the early ke2# series single carbs did come out with some larger jetting than the later 4k carbs

 

Mine ran ok on the 3kb carbs, but better when they were swapped for two single carbs on the 3kb manifold :)

 

Pretty sure I have a standard 5k carby in pieces in the shed somewhere, i'll post a pic if I remember later,

 

cheers!

 

That would be great. Ive been mucking around with these stock carbs on my 5k.

The best jetting I've got so far on the 4k unit is with 47 idle, 108/153 mains and a 90 power jet. It goes well under what but it's real lean at idle and low speed driving.

I'm think of going up to around 55 idle and 125 primary main.

Here's some other useful info.

Ke20 3k carbs came out with a 21mm primary Venturi as opposed to the 19mm in the later 3k and 4k units.

The Venturi, if your trick enough is interchangeable.

 

Okey doke,

 

Took some pictures, I have a vague idea when it comes to identifying stock carbs, (I usually unbolt stock and replace with weber's), in the first pic, the carb on the left (complete with orange paint) came off of a 5k purchased from an importers many moons ago, and the one on the right, I'm assuming its off of a ke70 4k, both appear to be 95% the same in appearance, Throat sizes from a glance look to be the same. I'm no expert when it comes to these.

 

 

Cheers!

 

 

Are you able to open the 5k carb and tell me what jet sizes it contains?

Yeah, it'll have to be during the week sometime.

Mine ran ok on the 3kb carbs, but better when they were swapped for two single carbs on the 3kb manifold :)

Hmm, I have a set that are rekitted with single carb kits (so single carb jets), but that didn't run as nice.

 

Turns out timing was out, running sweet as now, even idles!

From memory, the twin carbs run a smaller Venturi than the single carbs.

18mm & 22mm in the twin carb

 

21mm & 24mm in the single carb.

can anyone shed some light on the vacuum setup on KE70 4K Aisan carbs.

 

and how to keep the vacuum operated secondary working when installed in earlier Corolla's without all the anti pollution gear everywhere.

Edited April 1, 201412 yr by Tally