Morning all, I have a 93 Heritage Softail Classic I picked up recently because the owner was tired of dealing with some problems. Well I've fixed the trans and now I'm on to the fuel problem. The mikuni carb was installed in 2016 along with a 95 kit and six speed. The whole thing has about 500 miles on it. He told me it always ran quite rich. After cleaning the carburetor it leaks out of the drain at all times. The needle and seat fall apart as they should when clean. I've ordered a pressure tool to see if I need a new oring or if it's the actual needle and seat causing the problem . it leaks with the new one as well as the old cleaned up one.
I gues my question is this If i can't get the needle and seat to stop leaking what's a good carb to go with for the 93 model?

 

The Mikuni 42 would be my 1st choice. Next would be the Keihin CV off a later model (or the SE version - 44MM I believe)

 

Here's a pretty good video on float adjustment and testing.. The Mik is a very good carburetor.. I would fix it and make sure it has the proper jets.. Also here is a link to the manual to help out with too rich and all necessary settings.

https://www.mikunipower.com/Manuals/HSR42-48_Manual.pdf

The first video helps to explain needle adjustment.

The second video explains float adjustment very well..

 

I'm a fan of the CV40 carb, but since it is all set up for a Mikuni (also and excellent carb), I'd fix the Mikuni as 98hotrodfatboy says above....

Good luck with your repair...


PS- After I opened your post, I was afraid to read the entire post... Nothing good ever follows, " I have a 93 Heritage Softail Classic I picked up recently because the owner was tired of dealing with some problems." At least your issue seems like it should be manageable...

 

When you removed the float bowl, was there debris in it? Did you set the float heigth / drop when the new needle and seat was installed?

Older bikes can have debris or rust in the tank. Most any debris that makes it way to the needle and seat can cause the problem you are describing. So you might look in the tank to see if there is a significant amount of rust, or other debris in the fuel or bottom of the tank.

I'd remove the float bowl to check for debris in the bowl and seat, then check heigth etc. And you might consider adding an inline fuel filter if there isn't one already.

Paul

 

One thing to note - Some carbs the seat is a removable piece that has an O-ring that deteriorates. Not sure if the Mikuni you have is that way or not - but worth a check.
A carb can always be fixed - well unless it has catastrophic damage.

 

I would disconnect the fuel line and run fuel into a container througH a coffee filter or just a clear container and see what comes out. Tanks can get some serious debris. You will keep having issues if this is the case.

 

Morning all, thanks for the input. Okay I've cleaned the carb and put a new kit on it. It had been sitting a few years. The old needle and seat was pretty bad. The new one didn't line up very well and it was still leaking. I did a lot of lapping with some compound and got the leak fixed yesterday. At least on the bench. I have a clean test tank I'm using for running in the garage. Looking into the tanks they look pretty good for there age.But I will filter some fuel thru them before I reinstall. Hopdfully I'll get a little ride in today.

 

Let's touch on one thing. You don't have a 95 inch kit in your bike because that's for twincams. It's possible for you to have a 96 inch stroker kit with a different than stock crank.

This is important to figure out so that you can determine jet sizes.