Is my petcock the problem?

[DrWick]

My bike isn't starting so first up on the checklist is the petcock. I took it off and noticed that sucking on the hose with the vacuum portion doesn't allow any air or fluid through. It's stuck.

The Prime function works fine and fuel flows through there. Do I need to replace my petcock? Other solutions? Thanks.

[tom203]

My bike isn't starting so first up on the checklist is the petcock. I took it off and noticed that sucking on the hose with the vacuum portion doesn't allow any air or fluid through. It's stuck.

The Prime function works fine and fuel flows through there. Do I need to replace my petcock? Other solutions? Thanks.

Yes, best to replace petcock ( the successful repair rate is apparently low). BUT since you have flowing gas in prime spot, this is not the cause of not starting. Have you followed the link to Basscliff's site? lots of troubleshooting info to get you started.

[hampshirehog]

What bike and what tap?

[BassCliff]

Greetings and Salutations!!

Hi Mr. DrWick,

If you apply vacuum to the vacuum port on the petcock, fuel should start flowing while in the ON and RES positions. When in PRI position, it should flow without vacuum using just gravity feed. If it does not operate in this fashion then replacement is the best option. Rebuild kits are "hit and miss". For a little more info, see this article: Where Do These Hoses Go?

Anyway, let me dump a TON of information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed. I will put you on my prayer list.

Thank you for your indulgence,

BassCliff

[DrWick]

BassCliff,

Thanks so much for the warm welcome! This seems like a great community here. I bought this bike for cheap and am realizing that it's time for a lot of maintenance things mentioned on the GS greeting site. I'm a newbie at this stuff but every time I dive into something I get less and less intimidated by it and start to understand it more. I appreciate everyone's patience in the meantime!

I'm going to go through the whole checklist this winter but want to get a little more riding in this season if I can get it working at least somewhat reliably.

So I bought a new petcock and some new fuel lines. After inspecting the new petcock I was surprised to find that it also doesn't release gas when sucking on the hose. It makes a sound like it's moving something inside but no gas flows. Maybe I'm missing something on how it's supposed to work.

I did manage to get the bike running by pouring some gas through the vacuum hose into the carbs. Once it started I noticed small puffs of gas going through the vacuum hose in sync with the motor. Maybe this is how it's supposed to work? It was very minimal gas almost in the form of vapor.

I rode the bike around a while for that night and it would start with no problem. The next day it wouldn't start again. Even with using the primer setting on the petcock. Maybe something is wrong with the primer fuel intake? I took the hose off and it's not blocked in the hose.

Any thought you have would be much appreciated. It's a 1980 GS550 btw. Many thanks!

[tom203]

"pouring some gas thru vacuum line" ? make sure you revisit Basscliff's for correct hose hookup, since that vacuum line would only feed #2 cylinder.

Since your original post, I have developed a petcock problem myself. Took bike out for ride, ran strangely, pulled great at above 4k, but was definitely stumbling at low rpms ( where I usually ride ). Came back, pulled plugs and #2 was black, while others were nice. Hmm, big clue! put my clear hose on vacuum line and sucked- whoopie, fuel came down, informing me that my petcock was failing. Iffy rebuild kit for $20, or new petcock fot $50 ? Easy choice!