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-   -   Fuel Cap Vent and Lock Cylinder (https://www.klr650.net/forums/showthread.php?t=101547)

jeffsaline 04-15-2012 04:43 PM

Fuel Cap Vent and Lock Cylinder
 
I've recently cleaned two fuel cap vents and took a few pictures along the way. This might be helpful for folks wanting to clean the valves or lock cylinder. Lots of pictures so it might take a while for me to fully load the work I did.

This was done using a 2003 fuel cap but I'll guess other years are identical.

Shows the fuel cap being removed from the fuel tank.
https://www.klr650.net/photos/albums/...ap_Removal.JPG



Shows the fuel cap removed from the tank and ready for vent cleaning.
https://www.klr650.net/photos/albums/...y_for_work.JPG


Shows the exterior fuel cap cover removed.
https://www.klr650.net/photos/albums/...er_Removed.JPG

Shows the fuel cap interior cover removed.
https://www.klr650.net/photos/albums/...er_Removed.JPG

Shows the fuel cap spring retainer removed.
https://www.klr650.net/photos/albums/...r_Remeoved.JPG

Shows the springs around the perimeter of the cap. The brass plate covers the umbrella valves and helps locate the lock parts. Note the bushing pointed out by the phillips screwdriver tip.
https://www.klr650.net/photos/albums/...ck_Bushing.JPG

Shows the springs removed from the perimeter of the cap. The brass plate and lock parts are on top of the umbrella valves and lock cylinder.
https://www.klr650.net/photos/albums/...ts_Removed.JPG

Next post going to remove the valves and then the lock cylinder.

Best,

Jeff

jeffsaline 04-15-2012 04:50 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows the top umbrella valve and holder being removed. This valve is responsible for allowing outside air into the tank. In other words this allows the tank to suck in outside air but not pass fuel out if the tank is inverted.
https://www.klr650.net/photos/albums/...ve_Removal.JPG


This is the gasket between the top and bottom umbrella valve holders. Note the small hole in the edge of the gasket. This allows air to pass from outside the tank, through the bottom umbrella valve holder and gasket to the upper umbrella valve.
https://www.klr650.net/photos/albums/...et_Removal.JPG

Shows the bottom umbrella valve and holder removed from the cap. This umbrella valve is responsible for allowing high pressure in the tank to be relieved. Or in other words, this allows the tank to vent pressure to outside the tank.
https://www.klr650.net/photos/albums/...ve_Removal.JPG

Shows the umbrella valves at the top. Note the difference in the holders and the small hole in the bottom umbrella valve holder. This hole allows passage of air outside the tank to the area between the umbrella valves and into the tank to prevent vacuum in the tank.
https://www.klr650.net/photos/albums/...lla_Valves.JPG

Next is showing how to check the vent passages.

Best,

Jeff

jeffsaline 04-15-2012 05:26 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows stripped fuel cap and diagram showing vent passages in red.
https://www.klr650.net/photos/albums/.../10441/4_0.JPG

Shows spray straw in place to check for vent clog.
https://www.klr650.net/photos/albums/.../10441/4_1.JPG

Shows spray lube coming out vent indicating no clog.
https://www.klr650.net/photos/albums/.../10441/4_2.JPG

Shows spray straw in place to test vent to determine if clear.
https://www.klr650.net/photos/albums/.../10441/4_3.JPG

Shows spray coming out the vent indicating no clog.
https://www.klr650.net/photos/albums/.../10441/4_4.JPG

Shows the bottom view of the cap. Note the sealed vent passage from the bottom of the picture at 7 o'clock going to the middle of the cap to the left of the lock cylinder. This is not removable. It is a sealed part of the cap vent system.
https://www.klr650.net/photos/albums/...ssage_Seal.JPG

**CAUTION** NEVER blow compressed air into the cone shaped nipple when the cap is assembled. If you do the top umbrella valve could/will be forced partially through the hole in the brass plate holding the valve in place. If the umbrella valve is torn replacements are not available via retail sources.

jeffsaline 04-15-2012 07:35 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows latch and spring removed from interior cap.

https://www.klr650.net/photos/albums/.../10441/5_0.JPG

Shows latch and spring positioned for installation in interior cap. Push the latch toward the spring and push down on the center to compress the spring. It's easier this way than putting the latch in place and then trying to compress the spring and properly locate it. Lightly lube the parts. I use Molykote 44 Light.

https://www.klr650.net/photos/albums/.../10441/5_1.JPG

Shows the latch and spring properly positioned in the interior cover. Make sure you test the latch operation a time or two by pushing on it from the exterior of the cover.

https://www.klr650.net/photos/albums/.../10441/5_2.JPG

jeffsaline 04-15-2012 10:22 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows the cap with umbrella valves removed. Note the brass tab on the lock cylinder at the 11 o'clock position. With the key in the lock the tab is moved to the center of the lock cylinder and the cylinder is turned clockwise. The cylinder can then be removed by gently pulling on the key.

https://www.klr650.net/photos/albums/.../10441/6_0.JPG

Shows an exacto knife blade being used to move the brass tab towards the center of the lock cylinder for cylinder removal. Remember, once the tab is moved to the center of the cylinder the key and cylinder must be turned clockwise and then pulled out (down) from the cap. After the cylinder is cleaned and the bore of the cap cleaned and lightly lubed (again I use Molykote 44 light) the cylinder is installed. It will only fit back in one way.

https://www.klr650.net/photos/albums/.../10441/6_1.JPG

Shows the piece that connects the lock cylinder with the piece that connects to the latch. The seal is removable and note it goes with the lip up. It only fits on the lock cylinder one way. Again I use Molykote 44 light to lightly lube the seal.

https://www.klr650.net/photos/albums/.../10441/6_2.JPG

Shows the lock connector in place on top of the lock cylinder. The seal may need to be gently pressed into the bore with a small screwdriver.

https://www.klr650.net/photos/albums/.../10441/6_3.JPG

jeffsaline 04-15-2012 10:29 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows the bottom umbrella valve GENTLY folded back to make sure it is not stuck to the holder. I use my finger, the screwdriver is only for the photo.

https://www.klr650.net/photos/albums/.../10441/6_4.JPG

Shows the bottom umbrella valve in place on top of the first/bottom gasket.

https://www.klr650.net/photos/albums/.../10441/6_5.JPG

Shows the second gasket in place on top of the bottom umbrella valve holder.

https://www.klr650.net/photos/albums/.../10441/6_6.JPG

Shows the top umbrella valve GENTLY folded back to inspect it and make sure it's not stuck to the holder. I use my finger, the screwdriver is only for the photo.

https://www.klr650.net/photos/albums/.../10441/6_7.JPG

Shows the top umbrella valve installed on top of the upper gasket, bottom umbrella valve and bottom gasket.

https://www.klr650.net/photos/albums/.../10441/6_8.JPG

jeffsaline 04-15-2012 11:32 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows the springs in place around the outside of the cap. Lock cylinder and connector with seal are in place. The umbrella valves are all in place.

https://www.klr650.net/photos/albums/.../10441/7_0.JPG

Shows the spring retainer in place on top of the springs. Note the retainer lip is down to capture the springs.

https://www.klr650.net/photos/albums/.../10441/7_1.JPG

Shows the connector between the lock cylinder and connector on top. Note the small bushing in place on the small nub. This bushing is what contacts the latch. Guess what I lube the bushing with? Yup, Molykote 44 Light.

https://www.klr650.net/photos/albums/.../10441/7_2.JPG

Shows the brass plate in it's location. Note the nubs that are up. The brass plate will be put in the interior cover for final installation using a "special" tool. The interior cap fits over this but alignment is very difficult if you just try to lower on now.

https://www.klr650.net/photos/albums/.../10441/7_3.JPG

Shows the "special" tool needed for installing the interior cover and brass plate. You can make it from a piece of stiff wire or paper clip. I'm using a short piece of 0.040" safety wire as that's what I had when I did this on a trip in a hotel room.

https://www.klr650.net/photos/albums/.../10441/7_4.JPG

jeffsaline 04-15-2012 11:41 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows the interior cover inverted with the rubber gasket in place and the brass plate in the bottom. Note the brass plate has been turned over from the positon it was in when on the cap covering the valves. Note the nubs on the brass plate are down.

https://www.klr650.net/photos/albums/.../10441/7_5.JPG

Shows the "special" tool placed through the bolt hole so it can be moved to clamp the brass plate to the interior cover when it's turned over.

https://www.klr650.net/photos/albums/.../10441/7_6.JPG

Shows the "special" tool in place through the bolt hole clamping the brass plate to the interior cover. You must hold the tool with firm pressure so the brass plate remains in place when the interior cover is turned over to place over the umbrella valves and lock parts.

https://www.klr650.net/photos/albums/.../10441/7_7.JPG

Shows the interior cover inverted and ready to be placed over the umbrella valves and lock mechanism. Note the "special" tool is held firmly with pressure applied to keep the brass plate against the cover.

https://www.klr650.net/photos/albums/.../10441/7_8.JPG

Shows the interior cover in place on the gas cap. It's a bit touchy lowering it in place but gentle movements allow it to fit. Note I'm still holding the "special" tool firmly with pressure on the interior cover with my finger as it is depressed against the spring pressure and spring retainer.

https://www.klr650.net/photos/albums/.../10441/7_9.JPG

jeffsaline 04-15-2012 11:50 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Shows the "special" tool has been removed and one bolt is ready for installation. Note I'm still holding pressure on the interior cover as it is now spring loaded.

https://www.klr650.net/photos/albums/.../10441/8_0.JPG

Shows both bolts in place holding the interior cover to the gas cap. The latch should not move without the key being turned.

https://www.klr650.net/photos/albums/.../10441/8_1.JPG

Exterior cover cleaned and ready for the gas cap.

https://www.klr650.net/photos/albums/.../10441/8_2.JPG

Shows the gas cap on the exterior cap.

https://www.klr650.net/photos/albums/.../10441/8_3.JPG

Shows the screws in place holding the gas cap to the exterior cover. These screws go into plastic so be gentle when you install them. Note there are no o-rings on the hinged portion on the left side of the gas cap. They'll be installed next.

https://www.klr650.net/photos/albums/.../10441/8_4.JPG

O-rings have been installed on the hinged part of the gas cap. These seal the bolt holes of the tank. As you might guess, I lube the o-rings with Molykote 44 Light. The two bolts on the left have sealing washers on them. The cap is finished. Maybe check it a couple of times with the key before installing it on the tank.

https://www.klr650.net/photos/albums/.../10441/8_5.JPG

Last you install the cap on the tank. Look at the beginning photos if you can't remember how it goes. :razz:

You might also want to blow some compressed air through the tube in the tank and out at the bottom of the bike. Just remember to NEVER blow compressed air into an assembled fuel cap vent connection.

Best,

Jeff

floridalawdog 04-16-2012 12:02 AM

Re: Fuel Cap Vent and Lock Cylinder
 
Informative write up, so I will ask you a question because you seem to be knowledgable in this area. I have an 08 klr. I bought it last year with 4800 miles on it. Whenever I fill it with gas, or have a nearly full tank, gas is leaking out of my fuel cap. It seems to be coming from about the 5 oclock area, when lookng at the cap from the seated position. Do you have any idea what could be causeing this? All of the gaskets look perfect, and it locks down tight, so I cant figure out what is going on. Thanks

jeffsaline 04-16-2012 09:04 AM

Re: Fuel Cap Vent and Lock Cylinder
 
Quote:

Originally Posted by floridalawdog (Post 1109585)
Informative write up, so I will ask you a question because you seem to be knowledgable in this area. I have an 08 klr. I bought it last year with 4800 miles on it. Whenever I fill it with gas, or have a nearly full tank, gas is leaking out of my fuel cap. It seems to be coming from about the 5 oclock area, when lookng at the cap from the seated position. Do you have any idea what could be causeing this? All of the gaskets look perfect, and it locks down tight, so I cant figure out what is going on. Thanks

Maybe the top umbrella valve is dislodged allowing fuel to exit through the vent passage. The connection between the cap vent cone shaped nipple and the tube in the tank for the vent is not air tight.

So I think fuel could move past a dislodged top umbrella valve, through the passage and then at the junction of the cap and tank vent passage could leak. That would be the exterior of the cap/tank at about the 5 o'clock position.

Should only take you about 30 minutes to find out.

Best,

Jeff

floridalawdog 04-16-2012 12:39 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Thanks alot, ill check that out

revmaaatin 04-16-2012 02:13 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Something of note:
Why/when would you want to clean your fuel cap?

Bottom line:
The fuel cap vent system is always important; it appears to become increasingly important With increasing OAT, If the gas tank is not venting properly, fuel will not flow correctly. Just so you know, all bikes in this post have had the T-mod done and the vent lines are free and clear.

Background:
Both Jeff and my bike presented a fuel starvation/engine stumbling with higher OAT's.
Note: Our two incidents occur one year year apart.

In my case, the problem presents itself as fuel starvation; it starts easily reguardless of OAT, but , stumbles along at low power. AT temps above 95F my bike would not make 35mph, third gear, WOT. Oddly enough, as I climbed in altitude and the air got cooler, the bike ran better. I knew it was not altitude realted, as lower altitudes and early morning temps below ~95F the bike ran fine.


During my incident, my son was also his riding his own KLR; we bought gas in identical locations, using the same pump. His bike developed no problems. So it was a bike specific problem, not an outside problem such as fuel quality

Even though I initially thought it might be the gas, as we were both forced to buy 10% ethanol in the Yellowstone NP, it only occurred with my bike (daily) at increased OAT, even after many miles and gallons of gas consumed/replaced.

For me, the stumbling, never really a miss, and lower power began at temps ~95F and above; Jeff's temps actual temps might have been over 100F--the result were the same, the bike lost power and would hardly pull itself along. Jeff and I talked about this occasionally during the next year (prior to his bike developing a problem), but did not have a solid diagnosis/fix until his bike presented an identical scenario.


Through a number of thoughts and reiterations,
I initially attempted all sorts of (daily) minor trail side fixes-- I suffered through this for some 5 days before getting home again:
drain the carb; drain it again. (daily)
Try running on reserve, drain the carb again,
wrapping the fuel hose with insulated bubble wrap,
check the air filter = acceptable,
throwing rocks at the bike,
drain the carb again.

Later, during the year between the our individual incidents, someone (correctly) suggested opening the fuel cap and riding with the cap open to isolate the venting system--which I think Jeff was able to do to help verify his problem. He had a clear fuel filter that was not fully charged; when he opened the gas cap, while the bike was running, and wa-lah--mr. fuel flowed normally.

In his post, Jeff has warned: Do not blow compressed air into the system! :banghead:
Initially, Jeff and I blew compressed air into the system (using his very high quality and highly regulated air compressor) at only 5, then 10, max 15psi. I believed at the time it largely cleared my gas cap problem. Not fully tested yet but that will come later!

After some other list -people reported similar problems, Jeff suggested we surgically look into my cap. The initial pictures Jeff posted are from my 98KLR gas cap. During full disassembly, we noted that the rubber mushrooms were not damaged; but understood how they could have been damaged using high pressure air. We also noted that the internal passages that he shows blowing WD-40 into, did not flow freely = compressed air did not full correct the problem. We liberally added darb cleaner to the vent system and now believe it to be 'free and clear'.

I would like to publically thank Jeff for his excellent write up and his personal help with my gas cap; age has not been kind to my near vision :scream:
and projects like this are just out of my 'reach' with the present vision technology I now own.

revmaaatin.

Artful 04-20-2012 09:19 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Nicely documented - thanks for posting :nice:

Vandergraf 04-29-2012 09:06 AM

Re: Fuel Cap Vent and Lock Cylinder
 
Yes, nicely done. Thanks Jeff for the how-to and thanks revmaaatin for the clarification.

joednf 06-07-2012 09:31 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Long story short, I lost the keys to my '97, and now I have a new ignition switch and gas cap lock and their attendant keys. It looks like ig switch replacement is plug-n-play (feel free to correct me if I'm wrong), but getting the old lock cylinder out of the old gas cap (yep, currently locked on the tank) looks to be a true pain. Anyone know how to open a locked cap, or remove the lock cylinder while the cap is on the tank? Thanks.

I know my sig says '86, must've had a flashback.

jeffsaline 06-07-2012 09:58 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Quote:

Originally Posted by joednf (Post 1126819)
Long story short, I lost the keys to my '97, and now I have a new ignition switch and gas cap lock and their attendant keys. It looks like ig switch replacement is plug-n-play (feel free to correct me if I'm wrong), but getting the old lock cylinder out of the old gas cap (yep, currently locked on the tank) looks to be a true pain. Anyone know how to open a locked cap, or remove the lock cylinder while the cap is on the tank? Thanks.

I know my sig says '86, must've had a flashback.

What I would do is drill a hole over each hinge screw and remove them through the round plastic cover. Then I'd work the hinged side up while playing with the other side to get it to slip the latching action.

I think if a guy was careful with the drill and didn't go overly large a couple of plugs could be inserted and not look to obvious.

I'm thinking 1/4" or smaller would be a good start and then increase the size of the drill bit as correct hole placement is determined. I doubt a guy would have to go over 7/16".

Best,

Jeff

joednf 06-11-2012 09:36 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Hope I'm not being a dope, but how do I (lacking x-ray vision) know exactly where to drill the holes?

jeffsaline 06-11-2012 09:56 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Quote:

Originally Posted by joednf (Post 1128050)
Hope I'm not being a dope, but how do I (lacking x-ray vision) know exactly where to drill the holes?

You're not being a dope at all. I think it's easier to envision when the cap can be opened and closed.

I just took some measurements on my cap and it looks like the center of the bolts are about 1 1/4" apart. If you take a look from the seat side of the cap you can probably just see them or part of them from under the edge of the black plastic cap.

The arrangement will be something like:

bolt hinge bolt
O ---- O

It looks to me like the holes would be pretty close at about 1/2" in (toward the front of the bike) from the edge of the cap. That also looks like it's about where the ridge is on the top of the cap.

This is why I suggested you drill a small hole first and then enlarge it as needed. The screw heads are about 3/8" in diameter.

I'm comfortable in suggesting you don't need to go larger than a 7/16" hole.

I think if you hit the center of the bolt you might be ok going only large enough to insert a screwdriver to loosen the bolts.

Once the bolts are loose/removed I think you will be able to work the cap up. It won't be easy but it will be possible.

edit add: See the last picture in post #6 to get an idea of the hinge and hole locations in relation to the cap.

Best,

Jeff

joednf 06-11-2012 10:06 PM

Re: Fuel Cap Vent and Lock Cylinder
 
Never mind, I am a dope. Went through Jeff's photo sequence again, and think I'll make a semi-educated guess. If I miss, I'll just drill the whole circumference of the outer cap and tell people I'm trying to make the machine lighter (heh). This bike never pretended to beauty...just coolness.


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