Parts for 2 stroke leak down tester help?

[Mongolian]

Hows it going everyone,

So as what was going to eventually happen i I blew up my RGV and am now in the process of rebuilding it.
I am now at the stage where the bare engine is back together and i am wanting to do a leak down test to make sure i have actually put it together well and I'm not gonna get some weird lean conditions due to air leaks anywhere.

So i am trying to build a leak down tester as I would prefer not to pay $300+ for the motion pro one when its something I'm unlikely to use more than a few times.

I have gone off a few threads on other sites on how to build them but the part i am struggling to locate is called an adjustable rubber freeze plug i believe.
link http://www.asrcorporation.com/motorcycles/images/03CR250/PressTest/FreezePlug.JPG
I have tried places like supercheap and repco and they don't seem to know what I'm talking about, plumbing shops seem to call them drain pressure testers but i am yet to find one small enough (needs to be less than 35mm). Also tried fishing world and they had one but it was only about 15mm so was never going to expand large enough.

here is a link that describes what i am trying to build.
http://www.thumpertalk.com/topic/432226-pressure-testing-a-2-stroke/

Thanks in advance for any advice people could give.

[unstuck]

I would of thought the likes of plumbing world would of had one, you could try using an old shock absorber bush with a bolt and a couple of washers.:headbang: you may even be able to make a rubber bung thingy that you clamp into the exhaust port using the studs to push it in.:headbang:

[RDjase]

See if you can borrow one of your local radiator repair shop. they should have a selection of sizes for pressure test radiator and heater cores.

[F5 Dave]

Looking at his thread tool,

I made a spark plug fitting so it would fit any 2 stroke I owned. Got the same 3 way fitting from Paykel but just a shrader (tyre) valve brazed onto a fitting, no need for a tap.

& a fitting out of where he has the inlet bit that I put some thick tube that went to the sparkplug which was hollowed & had a tube brazed to it.

For the reed you will still need a round of plastic & ideally lathe a indentation so the manifold grabs onto it like on a carb.

RGV exh its been a while since I've seen one but on flush bolt on manifolds I just use a flat bit of steel with some rubber glued to it & a smear of loctite master gasket or similar. I think the RGV one is bolt on but with a recess, you could make up something to drop into that & still bolt it on.

Only use a bicycle pump to pressurise it, 8psi max. If it leaks down quickly spray the test set & the connections with soapy water & find the inevitable set up leak + reedblock which is a favourite area.

[ac3_snow]

I chopped/ripped/smashed the inside out of an old spark plug so only the metal thread remained. Got a long valve out of an old road bike tube (presta valve). used some araldite to glue it into the spark plug reminants. Got two small bits of alloy and drilled holes to fit over the carb manifold bolts and the exhaust. Bit of silicone on the alloy plates and bolted em up. Worked a treat I pumped it up to about 50psi with no leaks at all. Found out after I did this about the 8psi max which dave mentioned :facepalm:

265241265239265240

If you like, I live in blockhouse bay and you are welcome to borrow my adapted spark plug valve thing. made out of a B8ES plug as far as I know pretty standard two stroke thread.

[imdying]

As they say, block the holes however you like and have at it. On ours we put a gauge and schrader valve on each inlet rubber plug. Can't go wrong, and can see if it leaks through the centre seal (although a little there isn't a problem, it's a labyrinth seal, and a little leakage there is expected).

[F5 Dave]

I like to leave the manifold on as it is a fav area to leak. yes good point about a twin, lab seals do 'leak' unless running.

Those spark plugs are a bit of a fiend to gut.

[imdying]

I like to leave the manifold on as it is a fav area to leak. yes good point about a twin, lab seals do 'leak' unless running.

Those spark plugs are a bit of a fiend to gut.

Yup, and it's no harder to make a carb sized plug than it is to seal against the flange, imo.

Best of all, no gutting stupid spark plugs!

[F5 Dave]

For sure, I did it that way so I could plug into any engine. I have used plastic bungs for small inlets, but they shoot across the room if they dislodge, even with only 8psi.

[Mongolian]

Thanks for all the help,

I have managed to find a pvc plug that is just the right size for the inlet and another one that im going to use another pvc plug with rubber with for the exhaust and a metal plate from the exhaust studs to hold it in.

Hopefully will find out if it leaks tomorrow.