Topic: Newbie Question about the Petcock

[timeguy87]

Should the petcock when in the open position on the bench run until the tank is empty or close to it? Besides the reserve setting.

[Kevin D]

No, theres a standpipe inside that leaves about 2 inches of fuel for the "reserve" setting.

[timeguy87]

I know the petcock is not working properly because the bike is not getting gas. So I disconnected the gas lines and flipped the switch around to "on" and no gas. I took the tank off the bike removed the petcock took it apart blew every hole out with compressed air, reassembled and put it back on the tank on the bench turned it to "on" gas ran out for about 10 seconds then it stopped the tank was about 3/4 full. Is this what should have happened? If not what?

[tlbranth]

Figuring out where all the ins and outs are in this petcock takes a few minutes. But I would completely disassemble it. Take off the 2 small screws holding the on/off lever in place. There's a rubber thingy inside that directs fuel hither and yon and I'll bet that front section is bunged up. You may need a new rubber thingy. When reassembling, I use a little silicone grease to keep it from getting scuffed up. But disassemble and blow out all channels. Some are hard to get to. On mine, the ON worked fine but RESERVE was honked up - what you would expect from a rusty tank.

[timeguy87]

Thanks for the advice but I still dont know if the fuel should run out in the "on" position or just for a few seconds and then stop.It is now clean as a whistle. 

[tlbranth]

If the tank is 3/4 full, it should come out in buckets in the ON position. Did you disassemble it?

[timeguy87]

Yes. I don't know enough about it I did not see any goop anywhere a little build up on the spring but cleaned that. What should I look for?

[mystic_1]

What bike?  

With the petcock in the On position, fuel should run out until the tank is almost empty, then stop.  If you then switch to the Reserve position, most of the rest should flow out.

Sounds to me like you've goe sediment in the bottom of the tank that's clogging up the petcock.

Is your petcock like the one pictured?  If so remove the sediment bowl and see if the screen is plugged again.  If so keep flushing the tank until you get all the crap out of the bottom, then use a flashlight to inspect the inside of the tank to see if it's rusting up inside and releasing crap into the gas.

mystic_1

[timeguy87]

It is a 75 550 k1 a bit different fronm the one in the pic. I just kreemed the tank a few weeks ago. it is very clean inside.

[mystic_1]

Hmm you may have an extraneous flap of kreem blocking up the petcock bung.

mystic_1

[timeguy87]

could be i will check that tomorrow. thanks for the advice.

[w1sa]

Also, with the lever assembly out of the tap, and the lever held to the tap body in the 'ON' configuration, you should be able to see (or satisfy yourself) that the 'ON' passages/orifices between the upright stand tube thru the lever body assembly and sleeving to the inlet screen side, all line up.

Re-assemble  with this alignment in mind........ .

[timeguy87]

An update. Thanks to everyone for your help this is a great site with a great bunch of guys and I have learned so much. Here was the problem:gas cap vent was clogged and caused the tank to vaporlock.

[mystic_1]

Heh it's always the little things, isn't it?

Good catch.

mystic_1

[timeguy87]

Yes it is the little things....details, details, details!!!!