Petcock Issue

The filter goes on the other way but don't know if it matters or not. If it doesn't matter and someone knows that don't switch it around because any junk the filter has caught will flow straight to the carbs cleaning out the filter.

SilverTalon said:
When we had the tank off, the fuel would leak through the left side tube, but not the right side.

I'm not the proficiant with fuel lines. For now will I be able to ride with the switch on prime?

Again, worked before we Took the carbs and tank off
Click to expand...

Are you referring to the filter inside the tank and attached to the petcock???? If so clean that good with a solvent or something!
 
OleDoc said:
most inline filters have an arrow on them showing which way the gas should flow
Click to expand...

Yeah there wasn't an arrow on this one. I just went with what seemed logical. I put air through to see which way seemed to flow better. It's no big deal if I have to switch it around, All I've done was start it once, haven't ridden yet.

EDIT:Looking online it looks like everyone here is right, and it goes the other way. I'll switch it around later on
 
Last edited:
207kbyx.jpg


I turned it around, and took it on a cold ride around town quick. no issues this time. The only thing that concerns me now is that my idle drops from 1.5K RPM to 1.0-1.2K RPM every so often.
 
There is a screw on the plate that goes between both carbs and is connected to the throttle cable; you adjust this screw to get both sides of the carb to give the same amount of airflow. To do this, you measure the relative vacuum that the venturi (Houghmade pointed it out) on the carb boots gives off. You will need either a pair of vacuum gauges (expensive, and can be difficult to read) or a manometer (can be made cheap, and very simple to read). There should be quite a few threads here on doing this, so be sure to check those out!
 
I put in an order for new air filters and I'm thinking maybe spark plugs as well.

I'll see what I can do about measuring the vacuum as well.
 
OliverB said:
The vacuum actuated plunger in the petcock can also stick in the seat of the petcock if there is corrosion. A messed up seat can also result in the o-ring of the plunger not seating properly when the bike is shut off and fuel leaks into the carbs and runs into the air box(es). I'm having that problem with the one on my '79 now.
Click to expand...

Have a similer issue with my petcock. rebuilt it twice with differant vendors kits$$$$ but still leaking. some photos i see have the prime line facing down, mine came apart facing up. thought the line looked kinked that way but, up or down it still leaks.Read about a recall to replace these problem petcocks i.d.#32138 effective for xs400models. i have a 1978 e model and have had luck with more than that. any thoughts?
 
Has anyone heard of a safety recall#32138 for these petcocks. Mine on a 78 sx400e will not stop leaking after a ultrasonic cleaning // inspection and two rebuilds. The kits where gotten from differany vendors and had big orings that where not needed?
HELP
 
Same on mine, the vacuum hookup faces up, so the tube can wrap under the tank. I didn't change the position, but when I used new tube I just went round the frame
 
Aside from the petcock:

Old Filters:
21oy15v.jpg

New Filters:
2n8c1zd.jpg


Hopefully makes a difference. Waiting on new plugs to come in as well.
 

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