Pet cock problem, 450GA

[Guest]

Hi,

I just am returning to motorcycling after a couple of decades. I got a 1983 450GA a couple of weeks ago, although an automatic was not my first choice, the price was right. Overall, I am fine with the motorcycle given its age, but there are some issues.

I am experiencing a fuel problem. When the pet cock is in the ON position, the motorcycle dies after a few mile (tank full). Can get it running again when pet cock is on RES (still nearly a full tank). Leaving it in the RES position, there is no problem with the engine dying. I talked to the previous owner, and he said he did not experience such a problem, although he did not ride it much because his main motorcycle is a BMW.

One possibility is a hole in the pet-cock diaphragm, but cannot make a determination. According to the service manual, the vacuum from the carb pulls the diaphragm open to allow the fuel to flow when the pet cock is on either ON or RES; therefore I suspect that both the hose and diaphragm are ok because the motorcycle does not die when the pet cock is in the RES position. However, when I pulled the spark plugs, the right one was darker, indicating that it is running a little rich. But not so dark to be overly concern, at least not for now.

I did pull the vacuum hose to see if there is any residual fuel, which there wasn't as far as I can tell, although it could have evaporated by then. There was a small partial cut at one end of the hose. The cut did not appear to go all the way through, but I trimmed it off. Hose was still sufficiently long to reinstall with slack.

I did a quick search of the site and found a couple of useful threads, but not all of the information I would like.

Any advice or recommendation? Is there some other diagnostic test I should try? Is sealing the vacuum hose and running on RES a reasonable thing to do? One of the threads suggested this as an option. There are some pet-cock rebuild kits on ebay. Has anyone had any experiences with such kits?

Thank you in advance.

Paul

[Big Rich]

That is a weird one......maybe the tube that feeds the "on" position is clogged?

[tom203]

That is a weird one......maybe the tube that feeds the "on" position is clogged?

Yes, this makes sense. Best to carefully disassemble petcock and clean- too risky to just blow backwards, cuz petcock diaphragm might get damaged.

[pmong]

Thanks, any advice on disassembling pet cock

Tom and Rich,

Thanks, and your explanation sounds very plausible. I was told that the bike was in storage for a number of years, although the inside of the fuel tank looks fine when I look in. Nonetheless, there could be a problem that cause a clog when the pet cock is on the ON position. I do know that the rotating the lever is very difficult, requiring considerable force to move it from one position to another.

My service manual does not have any explanation on how to disassemble the pet cock. I know that I can remove pet cock from the fuel tank and the housing for the diaphragm from the pet cock, which are held by a set of visible screws, but not sure how to disassemble the other parts. There is no exploded diagram in the service manual to serve as a guide. I might be able to figure it out when I take the pet cock off, but would like as much information as possible before I do that.

Any advice? Perhaps an exploded diagram? I think I will get a rebuild kit, but are there other parts I will need when reassembling the pet cock? From a photo of the kit, it contains one O ring, a diaphragm, and a gasket. What is the best way to drain the fuel tank?

[mike-s]

read this link, it's a style of petcock that i have seen often, and am reasonably sure it should give enough of a guide for you to take yours apart safely. It also shows how gunged up the insides can get when left to their own devices & unused.

[Steve]

I find it interesting that it runs in RES, but not in RUN, even with a full tank.

I am wondering if, in fact, you are actually turning it to RES and not PRI.

When you move the petcock lever away from RUN, is the lever pointing forward (rotated clockwise) or backward (rotated anti-clockwise)?

If you moved it toward the BACK, it is actually in PRI, which makes sense, given the symptoms.

The diaphragm's o-ring could be stuck, blocking the normal flow. To fix that, remove the petcock from the tank, then remove the four screws on the diaphragm side. Pull it apart very carefully, so you don't tear the diaphragm. If the center is stuck, you might have to also disassemble the other side of the petcock by removing the lever (you will probably want to clean it up anyway) and poking through the center to get the center of the diaphragm loose.

If the selector lever is hard to turn, take it out, clean up the tapered edges with some fine sandpaper or a good Scoth-Brite pad. I use a wire cup wheel in my Dremel to clean the inside of the bore. Test fit the selector to the body. When it feels better, use a bit of silicone paste lube around the selector, then put it back together. After you fix the diaphragm problem, it will work and feel like a new petcock.

.

[JEEPRUSTY]

I use a dremel with fine metal polish on the bore of the petcock and on the o-ring mating surface. Do not mess with the spring if there is one.

[JEEPRUSTY]

read this link, it's a style of petcock that i have seen often, and am reasonably sure it should give enough of a guide for you to take yours apart safely. It also shows how gunged up the insides can get when left to their own devices & unused.

Wow that is a nice write-up. Hard to believe they can get that clogged.
Manufacturer logo is the same as suzuki's and the petcock is almost identical. Now to price the kawi units.

[BassCliff]

Greetings and Salutations!!

Hi Mr. pmong,

There must've been a half dozen members join in the last couple of years with a GA. I'd like to have a look at yours sometime. We're both in So. Cal. In fact, there are quite a few of us here in the area. (I feel a ride coming on.)

Anyway, let me dump a TON if 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 Rebuild Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. 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.

Thank you for your indulgence,

BassCliff

[bmac]

petcock

It has been through my experiences with the purchases of bikes that are 25 yrs old, replace. If there is a problem with the petcock rather than rebuilding them and I have, get a new one. At some point in time, the diaphragm will be become weak and allow gas to drain into the cylinder. The small metal tang inside will become bent and it will become problematic. Replace it and it will be basically something you won't have to worry about. OEM price of $61 and $2.30 for the o'ring gasket. Just my opinion, been there many times. Bob

[pmong]

Mike-S, thank you very much. Extremely informative, and I have it bookmarked.

Steve, good point, and I went out to double check. For RES, I rotate the lever clock wise (EDITED, originally wrote counter clock wise, but meant clock wise, from 6 o'clock to 9 o'clock when looking directly at the pet cock) so it points forward. There is an arrow at the end of the level, and it is in the direction of RES, partially covering the RES inscription. I also checked again with the Owner's Manual, and my setting correspond with the illustrative photo for RESERVE (page 10). So, I think it is on RES, which allows the bike to continue to run without dying. Also, thanks for the instruction on cleaning the selector lever and housing. Yes, it is very difficult to turn, extremely difficult.

Jeeprusty, thanks for the advice. Will leave the spring alone, unless absolutely required.

BassCliff, thanks for the warm welcome. Would love to meet other members, but it will have to wait until summer after I finish teaching. I am near the San Fernando Valley. Also, thanks for the links, and I have already visited your wonderful site. I hope to have some time to post a self introduction on the right forum later.

bmac (Bob), can you tell me where I can order an OEM pet cock and o ring? Tried doing a quick google search, but no luck. Rebuild kit is about $36 on ebay, so it sounds like a replacement would be worth the investment.

General comment. This forum is certainly amazing. Great information, very responsive members. Thanks.

[BassCliff]

Hi,

Your "mega-welcome" has an extensive list of OEM and aftermarket vendors. Feel free to do a little comparison shopping. Partshark.com, cyclepartsnation,com, Z1Enterprises.com are a few of my favorites.


Thank you for your indulgence,

BassCliff

[bmac]

Cliff has all the vendors listed. The price I had listed was Bikebandit. I thought you being in California would like to help out your state. But, to keep them honest(?) check the other sites has well. I shop at partshark and their prices are generally pretty good until the shipping gets thrown in. That's the way it is. Also, you may check your local dealer and see what there price is to order it. There may be a difference (good or bad). Also, welcome to the site. Bob