Sticky 400 petcock

[Organicjedi]

I want to go back to the original petcock on my 400. It's better quality than the Yambits one I had. The plan is to have it ultrasonically cleaned and vapor blasted.

The problem is the dial on it gets stuck to the point were the little lever feels like its going to snap off when I try and move it. I took it apart and am wondering if that plastic piece that opens and closes the fuel channels has swollen due to fuel exposure and age. Maybe something else?

I did manage to get that plastic piece out.

Anyone else had this trouble and found a solution?

[Yamaha 179]

I'm leaving town tomorrow morning and won't be home until Saturday evening and then I can look in my parts box but I am quite sure I have a good used OEM 400 petcock in there.  I'll look when I get back and I'll let you know if it still works and we can work something out if you haven't found a solution to your problem.
Lyn Garland

[SUPERTUNE]

Get rid of the stock junk oem and cheap china knock off's and go to the OEM Yamaha Raptor petcock, you will need to modify it to the stock 6mm fuel lines.
I have to upload all of the stuff I did on the old forum that now is lost in space somewhere.
Send me a email or text me and I can send you one ready to bolt on.
I put one on the yellow screamer 11 years ago and just now is starting to leak...so not bad for under $50. Throw the stock crap in the garbage.
Chuck

[Organicjedi]

Get rid of the stock junk oem and cheap china knock off's and go to the OEM Yamaha Raptor petcock, you will need to modify it to the stock 6mm fuel lines.
I have to upload all of the stuff I did on the old forum that now is lost in space somewhere.
Send me a email or text me and I can send you one ready to bolt on.
I put one on the yellow screamer 11 years ago and just now is starting to leak...so not bad for under $50. Throw the stock crap in the garbage.
Chuck

I'll shoot you a message. 

[Frank B]

+1 for the modern petcock, I followed chucks instructions that were on the old board. I used a TW200 petcock though, the raptor one wasn't in stock. There are two differences, the pressed in fuel line barb is smaller but it's removed to drill and tap anyway. And the intake tube sticking up into the tank is longer. I popped off the strainer, cut it shorter with a pipe cutter (about 1/2"), and put the strainer back on. The higher tube would cause you to have to switch over to reserve much sooner.

TW200 petcock

[SoCal250]

The info is in the Tech Library  ;)
http://www.2strokeworld.net/forum/index.php?topic=54.msg238#msg238
http://www.2strokeworld.net/forum/index.php?topic=54.msg239#msg239

[Organicjedi]

The info is in the Tech Library  ;)
http://www.2strokeworld.net/forum/index.php?topic=54.msg238#msg238
http://www.2strokeworld.net/forum/index.php?topic=54.msg239#msg239

[scully]

Its usually the set screw on stock petcock small washer under screw done :)

[Organicjedi]

Its usually the set screw on stock petcock small washer under screw done :)

Thanks for the tip! I'm getting one of Chuck's Raptor Petcocks. But I'm still going to rebuild the old one since I've got the kit. I'll give the screw trick a shot.

[Kawtriplefreak]

I guess I got lucky with the one I dug out of my parts pile. I put an Economy Cycle rebuild kit in it and made an adapter to fit it to my RZ to replace the vacuum operated stock petcock. Works like a champ 

[Dvsrd]

Its usually the set screw on stock petcock small washer under screw done :)

Thanks for the tip! I'm getting one of Chuck's Raptor Petcocks. But I'm still going to rebuild the old one since I've got the kit. I'll give the screw trick a shot.

I just came across these hose fittings for modding Raptor petcocks, just look a little sleeker than generic NPT elbows:
https://www.xs650shop.de/en/fuel-system/1374/petcock-fuel-line-fitting-900?c=161
https://www.xs650shop.de/en/fuel-system/1383/petcock-fuel-line-fitting-std?c=161

[Frank B]

Very nice
My only concern is the threads. British? Metric? I don't have those taps ...

[SUPERTUNE]

Its usually the set screw on stock petcock small washer under screw done :)

Thanks for the tip! I'm getting one of Chuck's Raptor Petcocks. But I'm still going to rebuild the old one since I've got the kit. I'll give the screw trick a shot.

I just came across these hose fittings for modding Raptor petcocks, just look a little sleeker than generic NPT elbows:
https://www.xs650shop.de/en/fuel-system/1374/petcock-fuel-line-fitting-900?c=161
https://www.xs650shop.de/en/fuel-system/1383/petcock-fuel-line-fitting-std?c=161

Looks like straight threads and a fiber washer to seal with, looks like more trouble to me as the ends of the petcock do not have machined surface to seal to.
Pipe thread fittings are way better to seal with...
Chuck

[Dvsrd]

Very nice
My only concern is the threads. British? Metric? I don't have those taps ...

My guess is metric, some variation of fine pitch. Maybe 7x1.0 or 8x1.0.
The Japanese are mostly wise enough to avoid BSP, NPT and other standards derived from the dimensions of human body parts ;)

[Dvsrd]

[/quote]
Looks like straight threads and a fiber washer to seal with, looks like more trouble to me as the ends of the petcock do not have machined surface to seal to.
Pipe thread fittings are way better to seal with...
Chuck
[/quote]
I do see that issue, but I believe that can be sorted with a flat file or a flat countersink drill. In any case this in necessary to index the fittings as required anyway.