This how-to describes the process of rebuilding the fuel petcock using a rebuild kit using a K&L rebuild kit specifically designed for the Seca II. Your petcock should be in good cosmetic condition to use this procedure.
Tools and Supplies:
- K&L Rebuild Kit -18-2777
- JIS #2 and #3 Screwdrivers
- Permatex Sealant #80016 (If Inlet Tubes Are Lose)
First of all, you should test the petcocks functionality to ensure it has a problem. Once you have determined it to have failed or is in the process of failing such as a slow leak when the bike is not running while in the on or reserve position, you then need to order a rebuild kit. They are fairly common, and a simple search on ebay or the like for "SECA II petcock rebuild" should yield a few results. What you are looking for in a kit is shown here below:
Once you have those in hand and ready to install your first step is to drain the fuel from the tank and into a fuel can by disconnecting the fuel line from the fuel filter and setting the petcock to the PRI setting which stands for prime. This setting allows fuel to pass through the petcock regardless of engine vacuum applied to the petcock's vacuum line. It would be ideal to capture the fuel in a fuel can to keep things clean and reuse the fuel you have drained once again. Unless the fuel is varnished up, or there is rust particles in the tank. If rust is present consider using this time to get the tank cleaned out and lined with something like POR15's Cycle Tank Repair Kit. There are two versions available, one for lining a tank that has not been lined once before and another that is for ones that have been previously lined with something like Kream which is not a product I can recommend based on previous experience. The kit that removes previous linings has an extra step in the beginning for stripping out the old liner.
It may be possible to remove the petcock without removing the tank off the bike. However in this write up my tank was already removed due to other works in progress. I suggest removing the tank to simplify the removal of the petcock and to keep the extra gas from leaking all over the bike. Now that you have removed the tank from the bike then remove the petcock from the bottom of the tank via the two screws as seen here:
This is what should come off of the tank. The high inlet tube is used in the ON position, and the shorter inlet tube is for RES (reserve). Check the screens to make sure they are clean and clear of any dirt, rust or grime. Also if they are missing entirely they should be replaced. These mesh screens are the first line of defense for foreign particles making their way to your carbs.
Carefully pulling them out you will then be able to remove the gasket that sits between the petcock and the tank.
Once removed clean the groves where the old gasket laid with a tooth brush or soft wire brush. You can see below mine had a bit of rust that came from the bottom of the tank.
And now it’s clean.
Moving on, we will start with the vacuum controlled valve which is on the backside of the petcock held in place by 5 philips screws seen here:
As you lift the cover off be sure not to lose the spring pictured below:
Also be sure the filter for the vacuum line does not pop out and get lost seen here at the tip of the screw driver:
Once you have the spring set aside lift the valve core out:
Separate the rubber from the plastic and pull it through the hole in the plastic making sure to keep note of which side the valve stopper is on. The pictures below can be used for reference.
Once this is removed clean the plastic up with a soft bristled tooth brush to knock any soot. Also clean the petcock housing, you can see where some rust particles where left in mine in the brown areas.
Now that the parts are cleaned up put the new valve gasket in place the same way the old one came off. Be VERY careful not to rip the new gasket when pushing it through the hole. You can see the big metal circle goes on the side of the plastic with the large circle cut out of it. Also I found it easier to put the gasket down my work area with the part to be pushed through the hole rolled up between my fingers like so:
With that all back together and everything lined up properly on the plastics making sure the tiny nubs are poking through the holes they should be on both sides, place it back onto the back of the petcock and put it back together being sure to keep the spring and tiny air filter in place.
Now with that done flip it over and begin on the other side removing the 2 small screws on the face that shows the writing of which direction the valve is turned. Behind this metal face plate is a wavey metal ring, be sure not to lose it.
Remove the cock and seal seen below:
Clean all the areas where gaskets once set. I used a q-tip with rubbing alcohol which seemed to do a good job.
Be sure not to leave any q-tip material behind in any of the holes. Put the new gaskets in place and put the cock back together. I found it easier to push the cock into place using some oil around the seal. If you pull it back some while installing it, the o-ring gasket will come off the surface it lays on, so do this in one motion of pushing it into place.
Put the wavy metal ring/washer and face plate back on and screw it back into place. The metal ring that looks all bent up is meant to be like this to hold pressure from the face plate to the cock keeping it pressed in. Do not try to flatten this ring as you will lose tension against the gaskets inside and cause leaks.
Put the gasket into the groves that were cleaned earlier. The reason they needed to be cleaned earlier instead of now was to prevent any dirt from getting back down into the holes and into the newly cleaned petcock and new parts.
Clean the surface area on the bottom of the tank where the gasket will rest. I used some clear nail polish on the surface rust areas that formed once my tank was etched and cleaned just to prevent any problems later on. It looks dirty in the picture below, but it works well.
Put the inlet tubes back into place as pictured. I have seen exploded view diagrams showing the larger tube switched and positioned towards the rear of the bike but this is incorrect. I have tested mine and found this is the correct placement. You may want to verify yours is the same way by pushing air through the longer tube while attached and have the petcock valve set to ON. With vacuum applied to the vacuum line of the petcock air should then come out. RES allows for both tubes to be used at the same time.
Check to see if either of the tubes are loose once pressed in and seated. If loose fuel will bypass the tube and you'll run out of fuel at the bottom of the tank instead of the proper height of the tube leaving you with a reserve amount.
If they're nice and snug simply skip this next bit, otherwise grab a small amount of Permatex Sealant #80016 or other sealant that is fuel/petroleum resistant.
Lightly coat the area on the tube similar to I have below here. The amount I used seen here may have been a bit excessive, you don't need much at all! My reasoning for putting it here instead of all the way to the bottom of the tube is not only because you don't need much but if it needs to be removed again later down the road it will be easier to detach the tube and clean the sealant out.
Take your time pressing the tube back into place to do it in a clean manner, I twisted the tube while pushing into place to get a more even spread with the sealant. If there is any excess sealant in addition to what you see pictured below simply wipe it up with a paper towel. Try not to get it in the channel the rubber seal rests in that presses against the bottom of the fuel tank.
Allow the sealant to dry according to the package instructions before adding fuel. If the sealant gets wet it may not set properly.
Bolt the petcock back to the bottom of the tank with the new bolts/screws.
Put your tank back together onto the bike hooking up the fuel line and the vacuum line. Set the petcock to on. If the sealant is dry or you did not need to apply any fill it with fuel and enjoy!
To test the petcock there should be no fuel coming out unless vacuum is applied to the vacuum line in both the on and reserve setting. Prime however will drain fuel regardless of vacuum being applied. You can apply vacuum to further test the petcock and ensure the valve opens when the engine is running. It does not take much vacuum to open the valve inside the petcock.
