'80 LF Carb help and Fuel Pump Issue

Andrew27 · Post by **Andrew27** » Wed Feb 05, 2014 4:52 pm

Rookie here again. Finally figuring out my 2 '78' LF 440's and so now I'm on to this '80 LF 440 I acquired and another '81 LF 440 parts sled as well.
Sat for 3 years, good spark and compression. Ran good on idle, put it under load and gave throttle it would die every time.
Took carbs off and cleaned them, all kinds of crud and junk came out. Replaced both of the tiny O-rings going into bottom of carb bowl.
Now I can't get it to fire. Dry plugs. Took line off from tank to pump, def. have gas there. Took both lines off pump going to the 2 carbs, no gas coming out when I turn it over? Bad pump all of a sudden? I know there are couple rubber diaphrams in there...a hole...maybe some ice or water? The vaccuum line from pump to engine is intact and looked pretty good.

Post by **Matt** » Wed Feb 05, 2014 7:12 pm

It's possible. For me, the fuel pump is the first thing to rebuild or replace when working on a sled. Especially since it's so cheap.

Andrew27 · Post by **Andrew27** » Wed Feb 05, 2014 8:47 pm

Is a new pump pretty inexpensive? What about rebuild kit?

Post by **Matt** » Wed Feb 05, 2014 9:10 pm

http://www.newbreedparts.com/newbreed/i ... uct_id=256

Andrew27 · Post by **Andrew27** » Wed Feb 05, 2014 11:38 pm

In regards to this '80 and '81 I'm working on, what else do I need to know about getting them in order for first pull starting and running?

harleysportster · Post by **harleysportster** » Thu Feb 06, 2014 4:55 pm

new crank seals if unknown replacement
check compression, looking for at least 100 psi per cylinder and now more than 10 lbs difference
check clutches
check over drive train, drain chain case, remove cover, inspect, add new oil
check all bearings on jackshaft and driveshaft
check suspension

Andrew27 · Post by **Andrew27** » Mon Feb 10, 2014 10:39 pm

Anybody familiar with the NOS Mikuni DF52 Fuel Pumps '80 + LF's ? Recieved one today for my '80 LF 440 and the bolt holes are in the middle of the pump, at least an inch higher in the air than what this factory one looks like I have now. Worried with the raised height of the pump now, is still enough clearance for the right side carb?

AirborneX4Special · Post by **AirborneX4Special** » Tue Feb 11, 2014 9:47 am

The OEM LF pump can be a problem given the close quarters in the engine bay. Is this pump taller than that? The dual outlet pumps available now can be used on an LF but need to be shimmed because the attaching ears are not on the bottom of the casting. I bought a sled that had one on the airbox, so I moved it and sealed the holes.

nick80lf · Post by **nick80lf** » Tue Feb 11, 2014 1:18 pm

DF52-73 will bolt right in

http://www.mikuni.com/c-fuel_pumps.html

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harleysportster · Post by **harleysportster** » Tue Feb 11, 2014 2:41 pm

nick80lf wrote:DF52-73 will bolt right in

http://www.mikuni.com/c-fuel_pumps.html

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X2

AirborneX4Special · Post by **AirborneX4Special** » Tue Feb 11, 2014 3:00 pm

The spare I have here is the DF 53-21-D. It does not bolt in easily because the ports aren't oriented properly for the LF. I assume it's why the previous owner bolted it to the airbox.

JDT · Post by **JDT** » Wed Feb 12, 2014 10:16 am

Can you pull the six screws and rotate the plate so it points in the correct direction?

'80 LF Carb help and Fuel Pump Issue

'80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue

Re: '80 LF Carb help and Fuel Pump Issue