fuelcock/petcock replacement

[rphillips]

Post number two & post number thirty six will work at least "as good", or "maybe better". And a bit cheeper. I'm trying to figure what have you got to lose.

I seem to recall that they will not ship to Canada but was going to have it shipped to Az. where a friend was wintering and advised Georges of that. So was left wondering.

Jonesz, did you look for one here? https://www.georgefixs.com

I had emailed them two inquiries before ordering the chinese one from Amazon. No answer either time. I did see where another poster had recommended Georgefixs but?

[Rich82GS750TZ]

Jonesz, did you look for one here? https://www.georgefixs.com

Just received my "Chinese Petcock" ordered through Amazon but believe all sellers are selling the same junk. Before going whole hog and installing the tank on my bike I tried the new petcock. It seemed to hold gas adequately and did not drip when installed in the tank. However, when I applied vacuum with a small hand vacuum pump to check how it operated as it would on the bike, it flowed fuel in Res. & On position. A problem arose when I removed the vacuum and the petcock continued to drip fuel. I now have a new petcock that has the identical problem to the 43 year old one that I was trying to replace. Looks to me like it is a crap shoot when ordering these knock offs. It may well be that you might have to order several before finding one that works properly. I have no intention of using the new one thinking that it will leak fuel and likely drip gas on to my shop floor creating a severe fire hazard. Gorminrider had it right when he asked how the petcocks resealed after vacuum was applied.
Don't know what to do now as I don't want to start ordering Chinese knock offs and waiting several weeks to find out the replacement is just as crappy as the one I received today after waiting over 3 weeks. The one I ordered was supposed to be and was advertised on Amazon as "shipped from Canada" but the seller (Topzan) was fraudulent when posting the ad and it was shipped from China.Really got taken here as I paid extra $ due to the seller stating my order would be shipped from Canada and thus would save waiting time. The ad is here: https://www.amazon.ca/gp/product/B08...?ie=UTF8&psc=1
Anybody have any other thoughts about what to do to repair/ replace my 1979 GS 850 petcock.

[dpep]

I bought a pack of 90 degree brass elbows that allow more creative routing without bending the tubes a lot.

Good idea. Do you have more detail on the product--picture or link perhaps? Most of what I saw was threaded and/or too thick to serve the purpose; hence the resort to thicker fuel line. But s proper fitting elbow would for sure be the better option.

[sacruickshank]

One thing I discovered when mounting on the bike is there a potential routing issue for the fuel line. The fuel nozzle on the oem points to the front into open space. On these the nozzle points to the inside of the bike and on the 850 the opening is less than an inch from the side of the airbox. I first tried routing the line by the most direct route turning it toward the front. Because of the tight space however that created a crimp in the bend.

I ended up routing the line from the carbs over the top of the airbox and down to the petcock nozzle which was still a tight fit but straight enough that there was no crimping.

It is not a deal breaker. Just keep in mind that you may have to do a little work around. I also thought about using some thick walled marine hose that I had in the garage for the line. It is stiff to work with, but it is not going to crimp.
...

I bought a pack of 90 degree brass elbows that allow more creative routing without bending the tubes alot. I've had cheap plastic fuel filters break due to the pressure from teh bends

[dpep]

One thing I discovered when mounting on the bike is there a potential routing issue for the fuel line. The fuel nozzle on the oem points to the front into open space. On these the nozzle points to the inside of the bike and on the 850 the opening is less than an inch from the side of the airbox. I first tried routing the line by the most direct route turning it toward the front. Because of the tight space however that created a crimp in the bend.

I ended up routing the line from the carbs over the top of the airbox and down to the petcock nozzle which was still a tight fit but straight enough that there was no crimping.

It is not a deal breaker. Just keep in mind that you may have to do a little work around. I also thought about using some thick walled marine hose that I had in the garage for the line. It is stiff to work with, but it is not going to crimp.
...

[sacruickshank]

After my failed attempt at converting the valve from my '81 550T, add me to the list of "just ordered a $20 petcock from AMZN, let's see how it works"

[93Bandit]

Vacuum shouldn't have anything to do with the valve sealing back, vacuum pulls the valve open against the spring pressure & the lack of vacuum only releases the spring so it can reseal the valve. Takes very little vacuum to open valve, put on a piece of hose on the vacuum nipple & gently suck on it with your mouth, you can actually feel the valve open & close. No gas in mouth unless there is a hole in diaphragm. Amazing how little vacuum it takes.

I understand the operation. My concern is if it does infact reseal properly after Vacuum has been applied and then removed. Simply put, will these valves start leaking after a dynamic test? The static test performed is very valuable information and has convinced me to try one. I just wonder about the results of a dynamic test?

[Gorminrider]

^^^but that is the rub- too weak a spring(too easy to open) means fuel pressure can do the same thing. Fuel pressure in a gravity feed varies while some some petcocks are built for fuel pumps where pressure is consistent. One may work for the other but my experience suggests they may not

[rphillips]

Vacuum shouldn't have anything to do with the valve sealing back, vacuum pulls the valve open against the spring pressure & the lack of vacuum only releases the spring so it can reseal the valve. Takes very little vacuum to open valve, put on a piece of hose on the vacuum nipple & gently suck on it with your mouth, you can actually feel the valve open & close. No gas in mouth unless there is a hole in diaphragm. Amazing how little vacuum it takes.

[Gorminrider]

Thank you for the excellent testing, Sir! That looks like the check ball style siphon, those things are great!

I only have one question about the valves: will a vacuum source affect how these valves seal? I wonder if they only sealed because you didn't apply vacuum to them yet?

Good-thought! it occurs to me a vacuum test comparison could be done with a large syringe and a hose to suit...the amount of vacuum needed for flow is gauged by the pull required...

as to "single-factory", personally, I rely upon it across Amazon, ebay, ali-express..if it looks the same- it is the same (usually the same picture is used) so beyond price and shipping I would recommend perusal of feedback- I pay a little more for the best feedback as a ratio per seller's number of sales...

[93Bandit]

Thank you for the excellent testing, Sir! That looks like the check ball style siphon, those things are great!

I only have one question about the valves: will a vacuum source affect how these valves seal? I wonder if they only sealed because you didn't apply vacuum to them yet?

[rphillips]

Yep, another reason to love this place, thanks