Petcock Advice

[gggGary]

BS34s use an oring to seal the float valve to the carb body (see above), it is nearly always shrunk and hard and lets gas leak AROUND the float valve. Always replace them when you open up a set of BS34s for the first time.
The petcocks like everything else is 30 years old they need new rubber parts and should be buffed. I have seen the MikesXS petcocks leaking after a short time. No problems do whatever you are comfortable with. If your gas tank isn't perfect inside running without screens above the petcock is asking for trouble. Perhaps use a wrap or 2 of stainless wire around the base of mikes screens so they stay on the tubes?
Slightly related the Yamaha petcocks are a decent design, the Old Kawi petcocks (KZ1300 to be precise) were junk. They depended on a nylon cone to seal against pot metal, it didn't for very long. More than one KZ1300 engine bent the LH (sidestand, low side) rod when gasoline filled that cylinder.

 

[xjwmx]

I need to add to what I posted that when I did the rebuild I didn't flatten the surfaces of the two halves as mentioned in gggary's article; it simply didn't occur to me to do it. And - when it finally failed it was between the diaphragm and the halves, because the diaphragm had lost enough of its rubberiness. Flattening the halves would have allowed it to last years longer I believe. But - I was in a pretty desperate situation when I did the throw in the towel mod (done on picnic table 20mi from hardware store) and I am satisfied it is the best solution for me.

 

[pahako]

I had the same problem. I purchased the carb rebuild kit from Mikes, and a manual petcock, and I haven't had any issues since.

 

[weekendrider]

+1 jetmechmarty, once sorted they like to be ridden.
Mikes manual petcock comes with a screen in the inlet barb, kinda.
There is a roll of screen stuffed in there anyway.
Like RG said you will want to seal the end and seam.
I didn't find this out till I swapped to a 90 instead of the straight.
And it wouldn't hurt to go through them with some emory paper the casting is abit rough imo.

 

[pahako]

Yes, the manual petcock from Mikesxs works very well. I use the 90 degree type of filter that www.650central.com sells. They allow easy routing of fuel lines.

Don't waste money on those filters that slip over the petcock intake tubes. The vibration from the bike cause those to fall off. Found mine laying in the bottom of the fual tank..................that's when I bought the 90 degree inline filters.

The manual petcocks have a fine screen inside the petcock itself. The screen is open at both ends, so I pinched one end and soldered it closed.

Where did you buy the 90 degree filter? I have not seen those before.

 

[retiredgentleman]

Where did you buy the 90 degree filter? I have not seen those before.

www.650central.com

 

[pahako]

www.650central.com

I guess if I had read your post I might have seen that. Thanks.

 

[blue900]

Man, Im starting to wonder if these bikes even like being ridden.

These bikes really like to be ridden (luckly because you will have earned it).
But it does take time, info from these Boards and some $ to get them right.
By dollars I dont mean replace everything, but some do.

I have 3 and all of them where sitting with low miles because the owners could not get the few problems sorted.

This board covers it all. Thanks everybody for sharing.

Dont give up keep learning and you will get to ride------------

 

[Lluber]

I can't give up.. love to ride to much.. new petcock is on the way. Carbs have been sonic cleaned and all gaskets where replaced when I did that. the inside of the tank isn't in the best shape.. So I figured I should get that in good shape while its off.. Stripped the paint off the outside.. noticed a fair amount of rust on the bottom sides (where the petcock connects to the tank) so I sanded, sanded and sanded some more until I got the tank rust free. Ill poke around for tank relining advice. Thanks guys!

 

[petew41133]

oh Yes a XS650 does best if it doesn't sit. Keep riding and ride safe!


1981 XS650 Special all stock

 

[fredintoon]

- - - Ill poke around for tank relining advice. Thanks guys!

Hi Lluber,
my tank lining advice?
Don't.
Tank lining compounds, if you buy the right one and if you meticulously obey the install instructions,
may just work until after you get the bike sold unless there's too much ethanol in the gas you are using.
Then you get the posts asking "How do I get this shit outta there?"
(Acetone/MEK cocktail soak, nb:- fire & inhalation hazard)
If there's rust inside your tank:-
Look up "Gas tank electroysis" to see an alternative use for your battery charger.
Or feed the tank a yard of dog leash chain and 2 quarts of kerosene then make like a maracca player.
Or strap the tank to a rotisserie.

 

[weekendrider]

The blue bike in my avatar was lined with Red Kote 6-7 years ago.
The state of MO mandates ethonol for anything less than 91 octane. No problems.
And the process isn't as tedious as other liners.
To clean the tank it doesn't get any easier than white vinegar.
The picture is some scrap strap I want to paint and use to hold a battery in.
Scaley and pitted I expect it to be clean by tomorrow.