Took me about 1 hr to do this and install a rebuild kit. I haven't run and tuned it yet so we'll see how this all goes. For now I just left the jetting the same as it was. It is basically taking an EPA adjusted carb and putting it back to pre EPA specs using an Andrews accelerator pump and drilling out the bowl for more fuel flow to the accelerator pump. I also purchased a rebuild kit and installed that which included new seals, float valve, and gaskets. Started snowing here so no opportunity to get in out on the road today to dial it all in.

This article is old as dirt and found on this trusty forum I'll let you know how it all goes.

https://skydrive.live.com/?cid=E2880...Q1JsimuJHA&v=3

 

Sounds like good upgrades. Anything that readjusts epa specs has to help.

 

the other upgrade is to remove the choke plate and the shaft it pivots on

this will allow the carb to pass a greater volume of air

 

The old trick of dumping extra gas into carb to cover up problem,as it gets too much gas at times . Better to make sure it starts squirting as soon as you open it up as some have too much space between pump rod and pump,also some have a bad plunger seal under squirter causing no gas if you turn throttle a second time as if going on and off throttle and back on again you have to pull squirter off to get access ,just give plunger in hole a slight rap or two with punch and "small" hammer. You may have to go up a second size on "LOW SPEED JET"to get it right after adjusting idle mixture setting which you want a little richer than needed.

 

Looking forward to your report.

Slight thread hijack warning!
Does anyone have a good understanding of the various Keihin Carb's used on H-D's?
I've seen reference to 38 mm, 40 mm, 42 mm sizes in the past, and have done some searching, but I can't nail down exactly what exists, when/why, and the differences (Other than throat size.)

If there are several sizes, do you just measure the I.D. of the throat to distinguish them?

And my very basic understanding is that smaller throats give more precise control at lower rpm's , larger at higher.
But are specific sizes better for stock EVO's, bumped compression, upgraded cams, etc.?
You can slowly go nuts chasing leads on the 'net when researching this.

 

I put my bike back together today and tried to fire it up and it just cranks and crancks but does not fire. Checked the spark and its good so guessing its not getting fuel. Didnt smell any gas either. I was in a rush so I will check it out again tomorrow.

The only thing I can think might be wrong was my 2 year old daughter while "helping" daddy managex to wedge a piece of her Goldfish cracker in the carb elbow where the fuel line attaches. I thought I got it out but it was wedged up there good.

Any suggestions?

 

First time I've heard that one. Old goldfish in the elbow.... I'd check there first.

 

I thought the standard carb was 40mm across just about every model ... did the 89 EG have a 38mm, and when did it change?

Can you slap a 40mm on them? I know a shop who just chucks them in the bin, they are cheap to pick up but fine to use.

I cannot find a parts list for it but if it has an L-shaped rod to activate the pump like the 40mm, leaving it off would cause that.

I've nothing to sell you ... so I'd say the OEM 40mm CV is fine enough if you work it a little. It's too lean on idle and the needle then a little too rich on the main jet ... which you'll hardly ever use anyway. Save your money for other stuff until you're really chasing 100 bhp.

 

38mm was used on Shovels and on Ironheads up to 1979, when the Ironhead went to 34mm. The 79-onwards had a high-idle linkage too.

Don't know about the 40 and 42. Do you mean the CV Keihins?

Yes you just measure the smallest diameter of the throat inside the carb. Easy way is to cut a strip of cardboard to the size you think it is and see if it fits in there nicely.

Pick of the bunch is the CV carbs. Lot of guys running 40mm CVs on Ironheads with big smiles.
The non-CV Kehins use about the same technology as the 1920s Scheblers and 1930s Linkerts. Kind of like a paint tin with some nail holes punched in it and an accelerator pump added on the side.

 

No matter what you do to a butterfly carb, the bike will still feel like it is towing a trailer full of bricks...

The best mod you can do to a butterfly carb is to turn it into scrap...

The best upgrade you can do to an `89 or earlier big twin is to replace that carb with a CV carb.