$17 Leakdown Tester

[Faded]

I've realized the importance of a leakdown tester but have always steered away from purchasing one do to the cost. After doing some research on the net and getting different ideas on how to make one I finally broke down and bought the stuff. As the title says, total cost was less than $17.00 (before tax). The sizes I make reference to are the ones my bike required. You might take the time to measure your intake and exhaust manifold to make sure you pick up the correct pieces. Also, with this tester there are no provisions for leaks that might occur around the various powervalve assemblies out there. Also, I am not trying to take credit for the design or the idea, I'm just basically passing along the information, giving people an idea for parts, and showing how easy/cheap one can be made. With that said, here you go.

The parts I used are as follows including the price I paid for each:

3/4" Pipe Pressure Gauge (used to test natural gas pipes), Home Depot - $12.98
3/4" to 3/4" Pipe Coupler, 1-1/2" Long, Home Depot - $0.74
1-1/4" Schedule 40 PVC Pipe Cap with 3/4" internal threads, Home Depot - $0.75
1-5/8" Expansion Plug, Local Auto Parts store - $2.49

Here is a picture:

 

[Faded]

When assembling the Pressure Gauge/Coupler/PVC Cap I would recommend the use of some pipe sealant/dope. I had some laying around so I didn't include this in the cost. My carb is a 38mm and the pvc fits very snug. I would imagine this would work for most bikes. For the exhaust I realize some of the smaller (125cc) bikes might be different. Don't worry, you can get the expantion plugs in 1/8" increments, they expand to 1/8" over there 'listed' size (my 1-5/8" will go up to 1-3/4") and the cost is about the same.

Here is another picture with it put together, I've shown the intake and exhaust manifolds so you get the idea of how it's suppose to fit:

 

[MXFastGuy]

Nice. Thanks.

 

[dthoms]

Faded,
Do you have to take out the reed cage to get an accurate reading?

 

[Faded]

MXFastGuy,

Thanks. ;)


dthoms,

I would leave the reed cage in. The reed cage is prone to leakage just like any other gasket areas of the the motor. This way you will be able to test the two seals between the motor/reed cage/reed stuffer.

 

[mylesc]

I built the same tester yesterday and will betrying it out today. I have a 97 CR250 and found that a 1&7/8" expansion plug works best to seal the exhaust port. Thanks for the cool tip on this DIY tester.

 

[Faded]

mylesc,

Cool! :cool: Let us know how it works outs. I built mine prior to tear down so it'll be a while before I get to use mine.

 

[Casper250]

What pressure are you supposed to use and what are exceptable ranges?

 

[Faded]

Start at 5psi, you shouldn't lose more than 1 psi per minute otherwise you need to start looking for a leak. Go Here and scroll down to 'Crankcase Pressure Testing'. :thumb:

 

[darringer]

Faded, I went to Home Depot to find the pressure gauge and they looked at me like I was from Mars! Can you tell me what department @ Home Depot it was in, and any other info on the gauge you have.
Thanks, Darrin

 

[Faded]

It should be by where they keep the metal pipes and fittings for natural gas lines or by the heaters/furnaces. I'm not sure how it is in your area, but our building code requires the natural gas company to come out and conduct/verify a pressure test of natural gas lines. The home owner supplies the equipment (gauge, cap on end, and air to pressurize the pipes) and since I installed a gas fireplace a couple months back this item was a carry over for me. I did make sure that they were selling them at my local Home Depot when I picked up the other stuff mainly to verify the price. If you want I can swing by tonight and get a part no. or SKU or something and I'll let you know tomorrow. ;)

 

[darringer]

If you can swing by and get the SKU that would be great! No rush, whenever you happen by there is fine.
Thanks again, Darrin

 

[Faded]

Darrin,

Here ya go:

30lb Gas Test Gauge by Prairie Home Product
Item # 51803
SKU # 7 39236 51803 3
$12.98/ea.

 

[darringer]

Thank you VERY much!

 

[Faded]

No problem! :thumb: Let me know how it works for you once you're done!

 

[mylesc]

The one that I built worked great and helped me find a few leaks (crank seals). One thing that I did differently that Faded's tester was to use a 90 degree elbow 3/4" to 3/4" coupler. This allows me to see the guage easier. The guage that I got from Home Depot was also a little different. It is a low pressure version that goues up to 15PSI which is fine by me. Thanks Faded for the great tip!

<a href="http://www.ecst.csuchico.edu/~mylesc/metal002.jpg/">Pic of my set up</a>

 

[mylesc]

Oops. I guess that I can't do HTML tags, so copy and paste this address:

http://www.ecst.csuchico.edu/~mylesc/metal002.jpg

 

[Faded]

mylesc,

Thank you! Your tester looks great. The only pressure gauge my Home Depot carries is the 30psi one I used otherwise I would have went with the 15psi one like you did.

Here's a link to your pic: mylesc's tester


;)

 

[mcracer]

These testers only seem to be testing pressure. What about pulling a vacuum on the engine?

 

[czmaniac]

Exactly, the only time a engine is in danger is when its "sucking" in outside air, therefore requiring a vacuum pump to draw the engine down for a successful test. You can buy an electric vacuum pump from McMaster Carr or a modeling hobby shop, they run about $29.95...Oh yeah, you'll need a vacuum guage, not a pressure guage...EJ

Originally posted by mcracer
These testers only seem to be testing pressure. What about pulling a vacuum on the engine?

 

[yz250flash]

Hey guys, did your guage come with that fitting? It looks to be 3/4" on one end by 1/8" on the other with a 1/8 threaded hole for the guage in the side. I can easily make something like this up but it looks as though you bought this piece that way.

 

[mylesc]

did your guage come with that fitting? It looks to be 3/4" on one end by 1/8" on the other with a 1/8 threaded hole for the guage in the side.

The guage that I bought from Home Depot came with the brass fitting shown below the guage. One end has 3/4" threads and the other end came with a schraeder valve installed. They're located in the natural gas accesory isle.

 

[cr250dave]

I know this is an old thread but I decided to show my version of this tool. I wanted to pull a vacuum instead of simply pumping it full of air so I used a vacuum pump I had laying around. You can get them at any auto parts store for I think around $15. It takes a lot of pumps to get the suction up but seamed to work great. Here's the pictures.
http://img.photobucket.com/albums/v82/XJ92jeep/DavidBikeVideo-Pics013.jpg
http://img.photobucket.com/albums/v82/XJ92jeep/DavidBikeVideo-Pics012.jpg
http://img.photobucket.com/albums/v82/XJ92jeep/DavidBikeVideo-Pics011.jpg

 

[Mike_socal]

How do you find exactly where the leak is coming from with a vacuum tester? I know it's more of a real world test but a pressure gauge seems more useful. With a pressure gauge it's easy to find out where the leak is coming from since you just look/listen for the bubbles.