Post-rebuild Petcock issue (No leaks tho)

Hi everybody,

Got my '82 Seca 650 (XJ650RJ) last summer and found this site around the same time. I've gathered lots of info so far! Thanks! But now I need to ask a question...

I developed a leaky petcock recently so I ordered a rebuild kit from my local supplier. With the help of my Haynes manual and this site I quickly disassembled, cleaned and rebuilt the little @#$!. The first time through I didn't replace the vacuum diaphram as it "looked" fine. Upon starting the bike up I definitley saw that was now the only leak I had.

Disassembled once again, replaced the diaphram, made sure everything was nice and clean. Made sure the diaphram and all parts faced the same way as prior to disassembly. Rebuilt, and started the bike up.

(At this point I'll add the the Haymes manual does include any info about the portion of the petcock where the diaphram sits...What the heck?)

Started the bike up and now I have no leaks whatsoever, but something is definitley wrong. It only runs with the choke full-on, and it runs like sh#t. Choke off, bike dies. It's obviously not getting enough gas, and obvioulsy has something to do with the work I've done. I've taken the thing apart and looked it over a few timesnow and I can't tell what the deal is. Any help from you guys?? Thanks in advance.

I'll have intermittent access to a computer for the next fews days as I'm away on a road trip that I was supposed to be taking the bike on!! But I'll be eagerly awaiting anyadvice you all have.

--Chris

 

When the petcock is on PRI, does the gas flow freely through it?

Did you re-attach the vacuum line from the carb holder to the petcock?

check the vacuum line, make sure it's not torn. A vacuum leak would cause similar symptoms.

 

Thanks for the reply. Yes, when on PRI it does appear to flow freely.

And, yes, the vacuum tube is hooked up and does not appear to be torn at all.

The bike only started running like this when I changed the diaphram. When I changed all the other O-Rings and gaskets and such it leaked, but ran fine. One I took out the old diaphram and installed the new, it started running like it wasn't getting a good mix.

Thanks again, and thanks for any other ideas anyone has.

Chris

 

My guess is that particulate from around the Petcock area has dislodged and passed down into the Fuel Bowls and fouled your Pilot Jets.

There is plenty of particulate that is small enough to pass through the Petcock Tower Filter, any Inline Filter and the Beenie Screens of the Float Valve Bodies and wind-up in the Fuel Bowl only to clog-up the works and make for pulling the Carbs and cleaning-out the dusty mess.

 

Does the engine run better with the petcock on PRI than ON? If it runs fine when PRI but not on ON, that would suggest a vacuum line / diaphragm issue. Otherwise it is probably the carb issue.

 

Thanks for those two ideas guys. That makes a lot of sense. I'll check it out tomorrow afternoon.

By the way, had I taken the bike on my trip I wouldv'e had a BEAUTIFUL ride there, and a MISERABLE ride home.

Chris