Suzuki 2 Strokes

This may have been brought up before, but I am doing it anyway. A recent post brought up the fragility of the check valves in the injector lines. Age is going to increase the number of failing check valves out there, so someone is bound to have already found a method to repair these things. I may be crying 'fox' too early but I think it has become time to seriously find a way to repair or replace with new check valves. Without these, we are inviting a very expensive and dangerous 'occurrence' to hurt ourselves and blowup our bikes. There is someone making 500 fork boots, Phil C and I have an inexpensive CDI out there, luggage racks, and instrument refurbishing services, etc. So does anyone have the knowledge/ expertise to do these check valves. These also affect other brands too, so the market may become slightly larger than Suzuki's alone. As time marches on, it will become an increasing situation where the owners of the world(?) will have to make more of the replacement parts as NOS dwindles and OEM quits making new stuff. I know it sounds grim, I just want to emphasize and kinda give a 'heads up' so it won't sneak up and bite us in our collective butts.

I've looked into trying to find replacement Banjo Ends.I know that there has to be some sort of Machine in this world that should take fittings like that.I dropped my search when Life took over full time but I think things will be slowing down a little bit for me to pick back up on my bikes a little bit.

I think this came up on the KTW board a while ago and I think that someone found check valves and banjo fittings at McMaster Carr.

A bigger issue on the GT750 is the "octopus" that snaps off arms and the pump. I have no idea how that could be repaired.

A bigger issue on the GT750 is the "octopus"

And the 550 and the 380, I might add.
Yes, that would be an ugly job to repair. I've always treated the "octopus" with great care because of the limited/non-availability of replacement "octopi".
As long as the main disk that sits under the pump is not cracked, I think a guy could come up with a small spigot-type fitting to screw into the disk where the line/s is/are broken off. The fitting would PROBABLY have to be custom made because of the small size....but it could be done.
Then it would be a simple job to hook a short piece of tubing from the spigot fitting to the snapped-off hard nylon oil line/s.
As to the check valve thing, the obvious problem is getting the correct spring. New ball bearings are not a problem.
This whole question needs more looking into, for sure.

This is a little help if you have some old octupi laying around (never throw them away). When I was building my GT750, I had one line that the check valve refused to work. I had another set with several bad check valves, but the one I needed was good.
I went to the hardware store and got a length os 1/4" aluminum rod. I cut off a 1" piece. I drilled all the way through to the line inner diameter. Then I counter drilled 3/8"deep the line outside diameter. This left me with a 1/4" shoulder in the middle. After careful measuring, I cut the line in a straight area. Trimmed the donor line and made sure the length was correct. I applied epoxy to the lines only so the none would get pushed in to the inner hole of the repair piece. It worked like a charm.
In retospect, I could have saved a lot of time by just going to the hobby store and gotten a length of model airplane fuel line.

Nahhhh,,no hobby store fuel line will do for that as good as your update. You did an EXCELLENT job on that repair, and once mounted you wont see the sleeve.

Coyote wrote:

That is really slick Coyote - nicely done !

Yep, that's a VERY nice job, Coyote !!!
And, yes, NEVER discard any "broken/worn" bits no matter what. It's amazing how some ingenuity and a little labour can resurrect many supposedly worthless bits.

presumably the check valve fix is because the valve is blocked and the fix allows the valve to be replaced and the octopus to be reused .
but isnt it a one way valve and the fix is not.
am i missing something or was it overkill by suzuki.
thanks mark.

As I see it, the problems are:

- Blocked check valve and zero flow
- Broken check valve flows both ways
- Broken feed line

Coyote very neatly found a way to cut a good valve off a spare bad octopus and splice it onto the the other bad octopus to replace that one feed line with bad valve. That's a clever fix.

Another fix has to be repairing broken lines from the Octopus.

The third possible repair has to be replacing the check valve with a good one.

For the last one it would be necessary, in the absence of a spare octopus, to find a replacement banjo and/or check valve with similar low blow off pressure and a way to attach it. It may be possible to use fuel line over a short stub of octopus leg leading to a new check valve/banjo.

http://www.mcmaster.com/#check-valves/=ayrvt9" onclick="window.open(this.href);return false; is a small collection, but I don't recall what the kawi Triple guys came up with.

The third possible repair has to be replacing the check valve with a good one.

That is essentially what I did. Because these lines are formed, you don't have a lot of options. I got lucky finding the line I needed having a good check valve.
They are easy to test. Buy a cheap plastic oil can and fill it with alcohol. It may be necessary to grind / file the tip so it fits the holes in the manifold. Pump the alcohol through the lines and mzke sure it is flowing freely from the banjo end.. Now hold it upright by the lines. If any of the lines drain back out, that check valves is probably bad.
A more thorough test is use the bajo bolt with 2 sealing washers and a nut. Now try to force the alcohol through the hole in the banjo bolt. Ii should NOT go in that direction.
Sometimes if the valve is not working due to being gunked up, you can free it up bay warking alcohol back and forth through tle line. The gunked condition occurs a lot on bikes that have 'set' for a long time. ie barn finds etc.

So my next question is, what is the cracking pressure on OEM check valves. The McMaster Carr valves look like they can work, now we need some plain banjo fittings to bolt to the engine. At least for singles and twins, barbed banjos and suitable fuel line could be used to replace the entire oil supply lines with check valves close to the ends, right? Maybe a replacement octopus with stubs could be reproduced by Clauss Studio's. With the stubbs, it would be easier to reproduce and either re-use the existing hard lines or make up all new oil lines, valves, etc. If a lot of triple owners would poney up now to make them, it would make Clauss have the incentive to make them. Face it, these plastic pieces are going to fail more quickly now mostly from age and partly from heating and cooling cycles as we ride our bikes. Better to actually have the parts on hand now, then scramble to get them and also head off a blown engine in the middle of no where.

thanks for the explanation of the why and how.
cheers mark

Some thoughts to get the creative juices flowing.

Rubber Renue by MG Chemicals does a pretty good job of softening carb intake boots and making them usable again. Might something exist that can do the same for the octopus?

If you do a Google search such as "brake line fitting", you get a lot of interesting little parts that might connect to the McMaster check valves and be usable for the octopus. Could then also use steel brake lines bent to the same shape as the octopus tubes.

All true, but I'm not sure that the lines need to be rigid or even semi-rigid. Flexible would work as well as a replacement.