Petcock Diaphram blew

sschering · Posted: May 27, 2009, 12:33 pm Post subject: Petcock Diaphram blew

I fairly sure the diaphragm in the XS400Ds petcock ruptured today.

After tanking up I flipped it back to run from Res.. got on and it was really hard to start.. Rode about 1/2 a block and it died.. Wouldn't start.. choked it and got it to fire but the RPM jumped to 3k and kept climbing to 6k then it just quit and wouldn't restart. WTF??

I pushed it to a parking lot close by to try and get it started again..
Nothing was really working.. I let it sit thinking it was flooded..

Tried again in 10 min and still won't fire.. it's not acting flooded..
I pulled the fuel line.. check the petcock in prime.. I got gas..
Hook it up.. put it back to prime and now it'll start.. idle is way low.. It'll die just by looking at the clutch wrong..

I rode it around the lot a few times.. It'll get home as long as I don't have to stop and idle anywhere.

So now it's home and I'm thinking should I rebuild the petcock for $30 or order a manual one from MikesXS for $40?

It's never leaked in the past so a rebuild should work.

Now that I'm thinking about it I guess it could be something super simple like a cracked vacuum hose. I'll have to test it out when I get home.

nudude53 · Posted: May 27, 2009, 2:20 pm Post subject: Re: Petcock Diaphram blew

Unscrew the brass fitting that the fuel line attaches to on the petcock and check for junk clogging up the wire mesh screen first before you dive into rebuilding them. I keep a small rare earth magnet under the tank in front of each petcock to pick up any rust flakes that may enter the fuel line before they get to the petcocks. They cost about 5 bucks at Radio Shack or Ace Hardware, they're about the size of a dime or a shirt button, works great.

TeeCat · Posted: May 27, 2009, 2:43 pm Post subject: Re: Petcock Diaphram blew

nudude53 wrote:

I keep a small rare earth magnet under the tank in front of each petcock to pick up any rust flakes that may enter the fuel line before they get to the petcocks. They cost about 5 bucks at Radio Shack or Ace Hardware, they're about the size of a dime or a shirt button, works great.

an... that's a GREAT idea!!!! just stick them to the bottom of the tank in front of the petcock mounting plates, yeah?

Yup... check the screens first, of course, but petcocks are one of those fairly low-dollar items that I personally would be inclined to replace the the nominal cost difference.

TC

nudude53 · Posted: May 27, 2009, 3:20 pm Post subject: Re: Petcock Diaphram blew

That's right TC, as close as you can get to the mounts.

Short story..... 2 years ago when I cleaned out my TX tank I put a couple pounds of roofing nails and BB's in it, strapped it to a BBQ rotisserie and let it run for a week non-stop. Shook everything out, rinsed it, painted it and put it on the bike. Last winter I replaced the tank with another one and when I removed the magnets I heard all kinds of stuff clattering around in the old tank. Seems that the magnets had picked up a few BB's and a couple of nails that I had missed the first time along with a bunch of rust. I'll never run another bike without them. Not bad for a 5 dollar investment.

TeeCat · Posted: May 27, 2009, 4:02 pm Post subject: Re: Petcock Diaphram blew

nudude53 wrote:

That's right TC, as close as you can get to the mounts.

Short story..... 2 years ago when I cleaned out my TX tank I put a couple pounds of roofing nails and BB's in it, strapped it to a BBQ rotisserie and let it run for a week non-stop. Shook everything out, rinsed it, painted it and put it on the bike. Last winter I replaced the tank with another one and when I removed the magnets I heard all kinds of stuff clattering around in the old tank. Seems that the magnets had picked up a few BB's and a couple of nails that I had missed the first time along with a bunch of rust. I'll never run another bike without them. Not bad for a 5 dollar investment.

LMAO!!

nudude, I went to Radio Shack on the way home from work, and the only RE ones they had were the little 3/16" diameter kind! Tiny! Shocked

Where can one get the dime-sized ones? And they have to be RE to be strong enough, right?

nudude53 · Posted: May 27, 2009, 4:18 pm Post subject: Re: Petcock Diaphram blew

Rare Earth is the strongest I have found. Can also be easily J-B welded to an oil drain plug as well, much more powerful than the plug magnets from the factory, and in case it does get loose for some reason the sump strainer will keep it caged in to keep it from wandering around in the engine.

Here is a hobby site where I have gotten them, a vast array of sizes and shapes.
(Moses Magnets)
www.easybuiltmodels.co...tm#magnets

sschering · Posted: May 27, 2009, 5:33 pm Post subject: Re: Petcock Diaphram blew

Try Michael's Craft Store.. They have em in 1/4" and dime size 4 for $3 or something like that. I have a few kicking around for my model airplanes.. Thanks for the tip.

TeeCat · Posted: May 27, 2009, 7:59 pm Post subject: Re: Petcock Diaphram blew

We have a Michael's nearby... I'll check!

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