Kawi2strokes.com Forum

REBUILDING THE NON-REBUILD ABLE CHECK VALVES

Tools
#800 wet sandpaper, #2500 wet sandpaper, 5/64 drill bit, 5pcs loupe set (harbor freight), new spring and ball kit, pressure tester. You can buy the gauge and pump ball on ebay, the pump ball is a blood pressure pump ball and the gauge should have no more than 15 psi of pressure max, 1/4" vinyl tubing 2' and 1/4" tee section. Your tester will look like an upside down tee with the gauge in the middle at the top. Test your system out for any air leaks so you don't have any problems when it comes time for testing.
Put the check valve between two pieces of rubber in a vice with the seat sticking out of the side, the seat is 1/8 at the end of the valve this is what you want to grab onto with a pair of pliers. Get a firm grip on the pliers or you will tear up the outside of the seat, the seat is soft so it will get chewed up anyway but you don't want to tear it up to much. With a firm grip push up and down until the seat breaks loose then wiggle it out, watch out for the ball when it comes apart.
Take the 5/64 drill bit and clean out the oil passage in the seat, use the 10x loupe to look at the seat (where the ball sits) see if the hole has sharp edges not rounded off.
To cut a new seat take the back of the drill bit and stick it through the back of the seat this will give you something to hold onto when you are cutting a new seat. Wet the #800 sandpaper and put the seat facing down on the sand paper and draw it back and forth a few times (make sure you keep it square (flat) you don't want to cut it at an angle, using the 10x loupe look at the seat( where the ball sits) and see if you have nice sharp edges, if you don't cut a little more, go slow you don't want to cut too much off. Once you have sharp edges wet the #2500 sandpaper and do the same thing to polish off the seat, using the loupe check for any burs.
To assemble put the new spring, ball and seat together. You can use the old spring, you need to stretch it to 17.00 mm and I recommended a new ball. After everything is put together place in vice and push the seat into the valve. Squirt carb cleaner through the valve to clean it out.
Connect to the pressure tester and see where it pops, it should be somewhere around 4.6-6 psi dry test( no oil) , your goal is to get it around 4.6-5 psi if it's to low you'll have to take it apart and stretch the spring (you don't need to stretch it too much) if the pressure is high use the back of the 5/64 drill bit inserted through the oil passage to compress the ball and spring. I compress the spring by pushing the drill bit down and taping the bit to the valve, you don't want to push too hard or you will push the ball into the spring, then let it sit for awhile and keep compressing and testing until you get the right pop. This can take anywhere from a few days to a week or longer. Once this is achieved 4.6-5 psi (dry) you can use 2-stroke oil to check the pop, it should be the same as the dry test, if that's ok test for leakage by using oil and 2 psi and let it sit for two days or longer, if the pressure doesn't drop your good to go if the pressure drops and you don't see any oil dripping then most likely you have a air leak. That's why you test for leaks in the beginning.

I need to correct the pressure release (pop) it really should be 4.6 psi not the variable figure of 4.6-5 psi.

Sounds like you did great work, pictures will be very helpful.

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the non rebuild able check valve notice the left side the seat is chewed up from being taking off a few times[][/img]
grab the seat with a pair of pliers, get a pair that has teeth to grab onto the seat, using the tip of the pliers will only slip off
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it looks like this after it's apart, the seat is on the left.
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the ball sits on the seat
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you can use the drill bit to clean out the oil passage then turn it around to help grab onto the seat when cutting a new seat
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the seat is faced down, grab the bit and seat and draw it back and forth a few times pull the drill bit up a little so it doesn't drag. You can move your fingers down just showing you what it looks like before you start
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the center hole of the seat should look nice and sharp. Polish and put back together.
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test it with the pressure gauge.
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if it pops before 4.6 psi you have to take it apart and stretch the spring, if it pops past 4.6 psi you'll have to compress the spring, put the drill bit in backwards and push down softly then tape the bit down to keep it compressed.
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But what happened to the plastic 1 into 3 line, and the plastic tube that goes over the barbs on the check valve?

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1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140. 2006 Ninja 500R Turbo intercooled fuel injected.

Very detailed write-up Thanks for doing this.
Question: What are the symptoms of a check valve not operating properly?

_________________
Jim
Atlanta, GA
1974 H1
1976 KZ400
1979 XS650 Cafe
1982 GPz750
2001 KZ1000P
1965 Mustang
1967 Triumph GT6
1976 Bronco
"If you didn't build it; it's not really yours"

I second the question DGA has above....how did you remove the the whole banjo fitting from the plastic 1 into 3 oil line without damaging it?

_________________
'75 Kawasaki H2C
'75 Yamaha RD350
'75 Honda CB400F
'86 BMW R80
'94 Honda XR650 'street tracker'
'04 Honda RC51
2013 HD Heritage Softail
2013 Triumph Speed Triple R

What I am doing is I'm taking on the task to rebuild the non rebuild able check valves and making new 3 into 1 oil lines since nobody has tried to reproduce these. I have an H2B to rebuild that's siting around in need of a 3 into 1 oil line, having purchased three sets of oil line which turn out to be junk and which all the lines are brittle at a cost of $450. I'm no expert at this just a regular rider trying to find a solution to fix this problem. So I have decided to learn how to rebuild the check valves and reproduce these oil lines. With the help of some of the members I came up with a solution on how to rebuild the non rebuild able check valves and I'm passing this on to the you the members because once the oil line is complete you'll need working check valves that you'll have to installed, rebuilding these valves is not easy, getting the right pressure release will consume a lot of time. I'm hoping to have the oil lines finish by June if all goes well. The top oil line is what the finish product will look like. [][/img]

Hopefully you can reproduce the plastic 1 into 3 oil line. I don't see the check valves as being non rebuildable, and nor do you, the problem is accessing those same valves without destroying the oil line itself. Good info, keep at the plastic line repro work, it's really the key to all this.

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1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140. 2006 Ninja 500R Turbo intercooled fuel injected.

The line you made looks awesome!

My only concern is if you ever have to take it back apart to service a fitting, would that mean destroying the line?

If you are going to reproduce these lines, would it be possible to make one much like the one Darth used to make that accepts the early style, ‘servicable’ banjo fittings? I know beggars can’t be choosers, but you’d have a paying customer here for one of those!

_________________
'75 Kawasaki H2C
'75 Yamaha RD350
'75 Honda CB400F
'86 BMW R80
'94 Honda XR650 'street tracker'
'04 Honda RC51
2013 HD Heritage Softail
2013 Triumph Speed Triple R