petcock problem?

[bigbyrd]

so if my bike is at " on" on the petcock i can ride for 1/2 mile then it will lose rpms and chug along and eventually die, and continues to die if i give it gas. but if i switch it to "res" starts up and rides fine, yes it has plenty of gas in it, ive checked for kinks, im thinking the petcock needs to be cleaned. and how would i clean it. or do you guys think it maybe something else?

[ben2go]

The vacuum diaphragm in the petcock is bad.It is cheaper to upgrade that to repair/replace it.It will eventually fail again with the original petcock.Here's my write up on the upgrade. http://gstwins.com/gsboard/index.php?topic=56352.0

[4twizzle]

There's a way to change the stock petcock to gravity fed by taking it apart, and rotating the plastic piece inside of it 90 degrees, but I can't remember which direction to rotate it in.  Once this is done, you can put a cap on the vacuum hose port on the carbs and eliminate that hose (and just leave the port on the petcock bare).  You can test the petcock by blowing into the out line and feeling which fuel intake port the air is coming out of.  It literally can't take more than 2 tries.   

For reference, my petcock settings and the mnemonics I use to remember:

up is reserved (nose in the air)
back is on (turn it *back on*)
down is off (if the forum is off, it's *down*)

so if my bike is at " on" on the petcock i can ride for 1/2 mile then it will lose rpms and chug along and eventually die, and continues to die if i give it gas. but if i switch it to "res" starts up and rides fine, yes it has plenty of gas in it, ive checked for kinks, im thinking the petcock needs to be cleaned. and how would i clean it. or do you guys think it maybe something else?

[bigbyrd]

thanks ben, ordered the crf petcock. just hope im mechanical enough to figure out how to cap it

[ben2go]

thanks ben, ordered the crf petcock. just hope im mechanical enough to figure out how to cap it

You're welcome.