How to rebuild your leaky or starving petcock

Thanks for the replies… I'll try to to get a hold of a camera soon and take some pictures. It looks like the center hole in your spacer is larger than mine. My spacer seems to hug more to the the metal cylinder (not sure what that piece is called) and is blocked from coming off on both ends.
 
Here is a picture of the part that came from my original petcock versus the replacement piece that was in the rebuild kit. The plastic spacer on the left is the piece I can't figure out how to get off.
 

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Looks like the same situation member 84tele was in: http://www.xs400.com/forum/showthread.php?t=13455.

Bought the correct rebuild kit but the petcock was non-standard. I don't know if he's resolved the situation yet.

Unfortunately I don't think your rebuild kit will work with your petcock. Depending on pricing you might want to buy a brand-new aftermarket petcock, and not use the rebuild kit, OR you could find a stock petcock used and rebuild it with the kit you have.

As an afterthought, since you have no way of knowing which rebuild kit would work... it might be possible to modify the petcock you have to accept the rebuilt kit. No guarantee that the vacuum action would work properly though.
 
Yep. Not sure what is is off of but that is not from a sohc xs400.
 
Does anyone know the spec and size of the valve o-ring? I pulled my petcock apart because it leaked like crazy and discovered that the o-ring was totally absent. Someone must have rebuilt it at some point and missed it somehow. Everything else appears to be in order and I'd rather not order a $25 rebuild kit with $15 shipping for one piece of viton rubber.
 
I measured an old one and got 2mm i.d 7.5mm o.d and 2mm thick. I would just go to a hardware store and get a few around that size just to be sure.
 
Really helpful write-up! My petcock is all gummy and gross at the tank and leaking. The leaking fuel looks like tobacco juice - yuck.

I'll get a rebuild kit and hope that has the tank O-ring, but does anyone know where can I get the in-tank filter?
 
if it looks like tobacco juice, then that is rust. you should consider plastic kote, or any of the fuel tank lining technologies out there. I have done the Por15, and another one. The second one I did was my fault for not unsealing the fuel cap hole, prior to riding it. (oops)

http://www.amazon.com/POR-15-49229-...=1420495683&sr=8-1&keywords=por+15+motorcycle

http://www.xs400.com/forum/showpost.php?p=114293&postcount=1411

obviously there are other plastic kotes systesm, use what is available locally, and you will have a local resources to ask quick questions too. I was able to run locally and get this.

(my experience :banghead: with rusty tank, one winter, I took my carb off, and stored inside for the winter. sometime before spring, I checked my carb, and there was red dust all over. If it wasn't for the Paper Filter, The larger rust particles. So the largest rust piece was the smallest one, that got though the paper. That was about 2 months of operations here in Minnesota, since I had to rip out my first attempt, and then went the last two months of the season with minimum rusting, I had hoped. Good luck
 
Hadn't thought about sealing the tank - thanks for the recommendation. There's very little rust observable from the main opening at the gas cap, but that doesn't mean there isn't any over at the petcock. I'll get a closer look when I have it off and see if the shop down the block does it.
 
This thread shows why this community is so valuable! Thanks and I encourage others to do the same when trouble shooting a repair. Thanks!!!
 
Now I know why my petcock gave me so many problems when I first bought the bike. It has no spring in it. I am glad I bought a whole other petcock after I attempted to rebuild the original one. I guess the previous owner had given the rebuild a go and lost the spring.

Same here. Does anyone know what size/strength spring goes in there? It's not listed in any parts diagrams I've seen. Why isn't it in the rebuild kit?
I hacked one from a spring assortment, but I'm guessing at the pressure it needs to seal yet open up with engine vacuum.
 
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