Tank Issues

[hellavelo]

First off-I searched and searched for this, but couldn't find anything quite like i'm experiencing. 

'87 K75: I have run my bike to bone dry empty-wont even think about turning over- twice now.  When I refill I am only able to get 3.3 gallons into the tank.  This seems to be about 2 gallons shy of what I should be putting in and my range is pegged around 140-150 miles.

Thoughts?  Is there anything in particular I should be looking for?

[roninvt]

Are you filling on the side or center stand?...not that it should make a 2 gallon difference. I would like to see a picture of your tank

[TX brick]

Is the fuel pump and mount OEM? Maybe the pump is not seated correctly in the bracket.

[hellavelo]

Thanks for the responses.  I will try to get some pictures tomorrow afternoon.  I am filling it on the center stand and the parts are all OEM.  How do I check if the pump is fully seated?

Thanks for the leads!

[TX brick]

Have you had this problem all along or did it just appear? To check the pump seating, remove the gas cap and see if the clips on the top ring of the pump mount are engaged in the bracket.

Possibly the last time the pump was removed, the clips didn't get fully seated.

[Chaos]

Could be the fuel pump inlet is too high, not picking up the lower couple inches of fuel.  Use  a flashlight to check if there fuel in the tank when it runs out of gas.  Filling it on the sidestand only makes a couple ounces difference, (on mine anyway, with the flapper valve out)

Other possibility is a previous owner used it to run drugs and left a stash in the tank.

[roninvt]

The stock tank holds 5+ gallons.  And apparently hellavelo's tank has a 3.3 gallon capacity from bone dry to full.  Either it is not a stock tank or there is a big block of weed butter taking up space.

[Motorhobo]

Maybe an aftermarket fuel pump installed funky? I have a Ford pump but have never run it dry to find out whether its in there right.

[johnny]

if its weed butter im hoping its not gmo... you can fedex to me for evaluation...

j o

[subforry]

My K1100 and the CA gas nozzle vapor are not a good match.  If I just put the nozzle in like a car it would come up short - maybe 2 gals.
Here is the trick the short vapor boots just need to be compressed slightly to allow the gas to flow.  With you free hand pull the vapor boot back, keep the metal nozzle in contact with the tank but just past the lip.
Not sure how your K75 is but if I fill mine to the top of the flap is about 5 gals at most.  The pump will start screening from sucking air when about 4.5gals are used.

When I first got mine I was only getting about 3.5gals.  Also I did find my pump to be loose.  Didn't help much, but it was not snapped in all the way.