New member, Q on K75S fuel light

[Neil_K]

Hello All,

 

I am a new user to this site (tho' I have been looking over the posts for a few weeks now). I am also a new rider, having just purchased my first bike; an 1987 K75S. I love it. The moto being 20 yrs old, I am making that error of seeking for problems that do not exist. I'm not used to vehicles that run SO well w/ 20 years of service. My bike has 29,000 miles, 1,700 of which are mine in my first month of riding. What follows is a post I made to another site, for which I received no responses. If anyone here can help out, I woud really appreciate it. Thanks so much in advance...

 

So a couple weeks back, I parked the moto on the sidestand and left it running to go into the bank on a cold morning. When I came out, the low fuel light was on (depsite plenty of fuel). I stopped and restarted the engine, light off....no probem...I figured that the angle of the tank exposed the sensor unit.

 

I hadyet to test at how many miles traveled I would absolutely need fuel, and figured the light worked due to that other episode. This am, at 215 miles since hte last fill, I started to get intermittency, and even one stall. I managed to get back to a service station and refill, and the bike took 4.5gal (my tank is supposed to hold 5.2). The light never came on. The bike definitely needed gas.

 

So... there appears to be a little malfunction w/ the light. Shortly, I will receive h-grips in the mail and will need to pull the tank for their install. Can anyone direct me to the appropriate lead to check this sensor? If possible, please use very newbie language, since I remain totally new to this.

 

Thanks in advance.

[duckbubbles]

I don't have my books handy right now, so I can't tell you which wire colors run the fuel level sensing.

 

But, the sensing system uses a float on a wire arm that is located on the right side of the fuel tank. The book says that you should get the warning light with approximately 4 liters of fuel left, about 1.2 gals. Since you saw it work once, it is probably functioning. Maybe it had an issue this one time. You were obviously running out of fuel.

 

Does your bike have the cone and fuel flap in the filler hole? That may be the reason that you can't get a full 5.2 gallons in it. If you remove the whole fuel cap with the four screws, three more screws will remove the cone from under the fuel cap and allow you to put more fuel in it. While you have the fuel cap off, if your fuel level is low enough, you can move the float and arm through it's range of motion and check for any binding. You can also check the light operation. There is a delay of a few seconds until the light comes on with the arm low enough to actuate it. Just turn the key on after you have access to the float and arm. And don't force any movements with the arm, either.

 

Frank

[Neil_K]

Thanks,

 

I'll give that a look when I pull the tank to install my heated grips, and see if I can:

1) pull the cone...yes, I do have one.

2) Move the sensor arm.

 

I appreciate your help!

 

Neil

[duckbubbles]

You can check the operation of the float before you take the tank off.

Get the fuel level low so you don't have to get all fuelly. Remove the fuel cap (4 Screws) and just reach in there and move it. With the key on and holding the float down, you should get a low fuel light in a few seconds, maybe 10. Make sure that the float will go completely down to the bottom of the tank with no binding. The wire arm might have gotten bent at some time and is not allowing full travel.

Incidently, the point at which the low fuel level light comes on is adjustable. I don't know how to do that, my local tech told me that some years ago, probably when your bike was new.

 

Frank