aux fuel pump on my 1980

maybe someone can shed some light on this for me. Ive done my share of motorcycle repairs and I dont quite understand fully the reason they installed this "pulse" type pump inline from the petcock to the carbs. I also noticed it is only energized (or so it appears ) to operate only when I depress the clutch lever. Im assuming mine does not work as I just picked up this project bike and wanted to get it running to confirm engine operation prior to moving forward with it. So I noticed that it flows a slight amount of fuel when you depress the clutch, and other times no. I guess my question is why do you need this pump as it appears that in a gravity system you really dont need it. Any info would help,
thanks

Hi Bill,

Go up to the top right of any page here and click on the FAQ tab. You will be directed to an old article that has been hot linked. Scroll down to #21 and read about the auxiliary fuel pump installation. I can't imagine that it was intended to be linked to your clutch but stranger things have happened.

Best of luck

Bill

Someone on the old KZ1300 Owners site said you should take this SOLENOID & The CAMCHAIN TENSIONER to a lake ...........& throw them both in !!!!.......as they are pretty useless & problematic.


The SOLENOID unit fitted to CARB 1300 models at the front of the airbox is not any form of pump. It just stops fuel flow when the ignition is turned OFF & allows it to flow with ignition ON.

It does not pulse or create any pressure what so ever. The only reason it was fitted was due to the fact MIKUNI who designed & made the TERRIBLE carbs did not include fuel overflow pipes on each carb body.
This basically means if you leave your petcock ON the fuel will stop at the SOLENOID rather than flowing straight thru them, filling the carbs, running down the inlets, past your piston rings & filling your entire engine with petrol........which is very common for owners who remove the SOLENOID & leave their fuel ON by mistake.

The problem is they are a very poor SOLENOID & often block or dont work, creating all kinds of starting & running problems, so most owners remove them.

You can often see OVERFLOW pipes fitted to most other carb bikes with a little piece of clear plastic pipe on the end for the fuel to overflow out of if the carb gets too full.

The moral of the story is.......MAKE SURE YOU TURN YOUR FUEL OFF WHEN YOU LEAVE YOUR 1300 IF YOU HAVE REMOVED THE SOLENOID !!

If you look at the links to the old site on this site, it shows the best way to route the fuel pipe (over top of carbs) for a GRAVITY fed supply. For what its worth I have tried all ways & this way is definitely best.

Pete F

Pete
thanks so much for that information, I would have thought it was a pump,,,lol
anyway, i already removed it and as a rule I always shut my fuel off.
thanks again

Bill.

I have no solenoid or fuel pump on my 1300 & routed my fuel pipes over the top of the carbs with a Fast Flow inline filter using 7mm rubber fuel pipe.
Everything works well with this set up.

I intend to buy a Pingle Petcock (with adapter)soon just to be sure the fuel in definitely OFF when it should be............as the standard 1300 fuel tap often leaks past even when in the OFF position.

Dont you just love old Jap Bikes !!!!

Pete F

I think you are right about the fuel line routing Pete. I 've had both an electric Mitsubishi and the mikuni/john deer vacuum pump and in the end went back to gravity feed.
Just a word on the fuel tap- I have used a Kawasaki vacuum tap for ten years and it has never given any trouble- engine vacuum opens the diaphragm and fuel flows, engine stops along with vacuum , fuel supply stops. No having to turn tap on and off.
Just my 2 cents.
Thanks