Mikuni Carb question

Liquifire · Post by **Liquifire** » Tue Jan 08, 2008 1:41 am

This is hopefully a simple question, but I looked through both of my manuals and couldn't find what the 4 (2 per carb) 1/8" fuel hoses are supposed to be connected to, if anything, on my Mikuni carbs? These are the 1/8" lines that come out right about dead center on the side of each carb. Are these vent lines? I also sort of expected to see a return line on each carb somewhere?

Thanks for the help,
Stephan

Liquifire · Post by **Liquifire** » Tue Jan 08, 2008 1:57 pm

ok, thanks for the info Rich. Have a good one.

Stephan

Danzig · Post by **Danzig** » Tue Jan 08, 2008 2:03 pm

Here is a pic......

johndeere96 · Post by **johndeere96** » Tue Jan 08, 2008 4:57 pm

Hello and many thanks to Paul and Rich.

The vent line photos for the 80 Liquifire were very helpful. They were a confirmation
of how I plumbed my restoration.

I have one more question. Could either of you fellows post a photo of how
the upper fuel tank spigot plumbs to the fuel line on it's way to the fuel pump?

I suspect there is some sort of metering tee device that interfaces the two but am not sure. (Need the part number if this is the case)

My restoration was a complete basket case on arrival, so I have not seen the fuel system assembled.

Here is a link for a photo of the project, scroll down the page to "A nice Liquifire"
http://acscc.com/gallery/showgallery.php?gid=600

Thanks in advance
Dave Veitch
(johndeere96)
Barrie, Ontario Canada

Danzig · Post by **Danzig** » Tue Jan 08, 2008 7:56 pm

The 1980 models did not have the high mounted fuel spigot, I think that was an 83-84 mod.

johndeere96 · Post by **johndeere96** » Tue Jan 08, 2008 8:09 pm

Hi Paul

Thanks for the reply

Looks like I need to clarify my request.
The fuel tank on my 1980 Liquifire has a lower nipple for fuel feed and a upper nipple for what appears to be a return line.
I am looking for a photo of how this upper nipple plumbs into the fuel line as a return.
This unit is a 1980 model year.

Dave

JDT · Post by **JDT** » Tue Jan 08, 2008 8:18 pm

The top nipple is a vent line. Keeps the tank the correct size.

Todd

Danzig · Post by **Danzig** » Tue Jan 08, 2008 8:21 pm

johndeere96 wrote: Hi Paul

Thanks for the reply

Looks like I need to clarify my request.
The fuel tank on my 1980 Liquifire has a lower nipple for fuel feed and a upper nipple for what appears to be a return line.
I am looking for a photo of how this upper nipple plumbs into the fuel line as a return.
This unit is a 1980 model year.

Dave

That tank is not 1980 equipment.

johndeere96 · Post by **johndeere96** » Tue Jan 08, 2008 9:27 pm

Hi Paul
Thanks again

I have to go with you on this.
I have not seen a factory 1980 Liquifire tank, fuel system.
That is where my questions start.
With the upper and lower spigot as described, looks like you make it a later model.
Fair enough.
I need some advice, Does this upper vent/line spigot need to be brought into the fuel delivery side as a return?

Please advise.

Dave

JDT · Post by **JDT** » Tue Jan 08, 2008 9:40 pm

Answer... NO. it is just a vent.

Mikunis do not use a return line.

Todd

Danzig · Post by **Danzig** » Tue Jan 08, 2008 9:45 pm

johndeere96 wrote: Hi Paul
Thanks again

I have to go with you on this.
I have not seen a factory 1980 Liquifire tank, fuel system.
That is where my questions start.
With the upper and lower spigot as described, looks like you make it a later model.
Fair enough.
I need some advice, Does this upper vent/line spigot need to be brought into the fuel delivery side as a return?

Please advise.

Dave

I have only seen one later model L-fire and I think the vent has a fitting like what the main fuel line coming out of the tank and I think there is a T fitting which routes that line downward leading nowhere...I cant say 100% for sure. Beings I have only seen one.

johndeere96 · Post by **johndeere96** » Tue Jan 08, 2008 9:50 pm

Hi Paul
This from jdparts.com

This exploded diagram represents what I have.
http://jdpc.deere.com/jdpc/servlet/com.dee...PageServlet_Alt

Is it a 1980 unit or a modification?

Dave
johndeere96

Danzig · Post by **Danzig** » Tue Jan 08, 2008 9:58 pm

I need to edit my last post by saying its not a T but an elbow and I will say again, I have only seen one of these setups on the 83-84 L-Fires in person. I have 2 80's and had an 81 and both only have one fitting in the gas tank. I do have one brand new tank with the 2 fittings as you are describing and the top fitting is a vent and its for the 83-84 L-fires. I dont know what else to say.

johndeere96 · Post by **johndeere96** » Tue Jan 08, 2008 10:06 pm

Hi Paul

OK this is starting to make some sense.

Another exploded diagram I found lists the top spigot/line as being vented with 3 mtrs of fuel line not connected to anything. Made it look like a not terminated vent.
Many thanks for the information.
Will advise the outcome....

Best Regards
Dave
johndeere96

johndeere96 · Post by **johndeere96** » Tue Jan 08, 2008 10:26 pm

Hi Paul

Looks like this unit is a Frankenstein.

It is a 1980 model year, I am certain of that. VIN Number etc indicators.

It may have suffered many modifications before I got it for restoration. Like I was saying, I found it in basket case state March 2007. It was destined for the boneyard, but foolishly I rescued it.
It's a complete running piece now. Taking up storage space in the shop.

The last John Deere I owned was a 1976 Liquifire 440, purchased new and run one season.
I sold it late 1977 or early 1978. I have lost track of it's whereabouts. I was young and foolish then.

Here's the funny part. I traded a 75 Merc 440 sno-twister for it.

I kick my derriere every time I think about it.

Best Regards
Dave
johndeere96