[docjcwatson]

This applies to a two stroke twin cylinder motor. The information contained can also be applied to single cylinder and tripple cylinder two-stroke applications.

This is a "How-To" on making your own leakdown tester. This is going to explain step by step exactly what you need to do in order to make a homemade leakdown tester.

First. You will need to measure the inner-diameter of your intake. This is the size of PVC pipe that you will need to buy. Get as close to the actual size as you can. Without going over.



Second. You will need to measure your exhaust outlets inner-diameter to find out what size freeze plugs you will need. Same thing. Get as close to the size that you need as possible without going over. NOTE: You will need to get the size that goes up to the size that you need. For example; if you have an ID that equals 1 3/4". You will need to get the size that is 1 5/8" to 1 3/4". The one that is 1 3/4" and bigger. Is going to be too large for you.

Then you will need to go out and get all the supplies. All of these parts should be fairly easy to come by.



Expandable freeze plugs. Purchased at Advanced Auto Parts.



1 1/2" PVC Schedule 40 pipe. Purchased at Lowes.



Two 1 1/2" PVC Schedule 40 caps.



Tire pressure gauge. NOTE: Needs to be easily readable at 6PSI. Purchased at Advanced Auto Parts.



Metal Tubeless valve stems. NOTE: The ones that have a nut are easier to get tighter. Purchased at Advanced Auto Parts.



Handy Pack of PVC cement, too include primer and cement. Purchased at Lowes.



Now. On to the fun. Measure out about 3 inches of PVC pipe. Mark to make a cut.



Then cut it. Doesn't have to be perfect either.

Now. Measure another 3" section out. And cut that also. Still doesn't need to be perfect. Should have two now.

[docjcwatson]

Set the two pieces of PVC pipe on a flat surface. Pick a side that you want to have the caps on. Use the purple primer out of the Handy pack to prime the ends of the pipe. The brush is inside the can of primer. Might be hard to open the first time. No big deal.



Do the inside of the caps also.



Then apply some cement the same way. Be careful with the cement. You do not need a lot. When you are done with applying the cement on the outside of the pipe and on the inside of the caps. You should put the caps on top of the pipe pieces. Press down as hard as you can to make sure to get the best seal on the cement.



Ok. The tire gauge that I bought needs a little modification. So, we are going to open it up and look at the bottom.



The little brass flat head screw in there needs to be loosened and removed. When you loosen that screw, you'll notice that the outside came undone too. Unscrew the whole thing. Including the outside cap. Should look like this when completed.



Now that is all taken care of. We can move onto the drilling. You are going to have to find a drill bit that is small enough for the end of the tire gauge. Then you are going to drill the end of one of the caps with this bit.



Should look like this.



Test fit. The end of tire gauge should now have a threaded end on it. You do not want to go so big that you can not thread it in to place in the cap.



Take the tire gauge back out. Prime and cement the hole.



Now take the tire gauge and screw it into permanent place. Make sure no cement gets on the inside of the pressure gauge.



Done with one!

[docjcwatson]

Now onto the second one.

Take your valve stem and take it apart. Should look like this.



Now, take the other pipe with cap and drill it the same way that you did the first one. With a bit that is slightly smaller than the valve stem threads.



Should look like this.



Test fit. Screw the valve stem in the opposite way, so that you know the hole is not too big for the stem.





Take the stem out and prime and cement the hole.



Now, slide the valve stem into place on the inside of the pipe. Screw it into place. Do not get cement on the top or bottom of the vavle stem. Then all you have to do is, screw the washer and nut back on the top of the stem. NOTE: If you can fit the other black bushing on top of the cap around the valve stem, I strongly suggest you do. It will only help. Not totally necessary though.



Looks like this when you look inside the pipe.



This is what they look like thus far.



Use a little bit of sealant on the holes we drilled.

[docjcwatson]

Looks like this now.



Done with the leakdown tester!!!

Now for the process.

Put the expandable freeze plugs in the exhaust outlets and tighten them down!! This is very important. They should be air tight!



Take your pipes and put them into the intakes. NOTE: I used some more sealant where the caps stop on the pipe. Not necessary.



Hook up your tire inflator. Inflate to 6PSI only!



I use an electric tire inflator made by Bell to keep pumping air in, so that I can find leaks. If your motor does not hold the air. Take a spray bottle of warm soapy water, re-inflate to 6PSI and spray around different parts of your motor to find the leak.


Hope this helps you. Most of this info came from my buddies off this site. Chad, Austin, Dave and Shayne. Thanks a lot for all your guys' help.

If anybody sees anything wrong with this info, let me know ASAP! So I can get it right!

[JP374]

cool post, Thanks for sharing

[badassbanshee479]

cool! thank ya for sharing

[QuickSand]

Making mine this weekend! Thank you much Doc!

[Backcountry]

Good stuff!!!

I might suggest a slightly better gauge.

From Mcmaster.com

4089K11
(Same as 4089K61)
Multipurpose Gauge +/-2% Mid-Scale Accuracy 2" Dial, 1/4" NPT Male Bottom, 0 - 15 PSI
$8.52 ea

[docjcwatson]

That's exactly the best kind of gauge to use. I just used one that I knew was easier to get ahold of for most people.

Glad you guys like it. Keep the ideas coming.

[94sheeMAN]

great info! saw this and went and bought my parts... thanks!

[big daddy hog nuts]

how much do u have total in this???? i have a dual gauge leakdown tester, from the site (boating) scream and fly for 65 bucks

[docjcwatson]

65 bucks aint bad at all. How much was shipping though?

All together i'd say 30 bucks.

[big daddy hog nuts]

that was shipped as he builds them (pieces them together) but still nice, he calles them the BALT

big azz leakdown tester lol

[dajogejr]

Nice write up Doc...
I bought mine from RB Porting in MI. He usually sells them on Ebay for 50 bucks...
As said, a life saver. saved me from running my motor with intakes leaking...

And my buddy borrowed it with a big DM and found all kinds of places in the cases leaking (epoxy, around the studs, etc.)

[docjcwatson]

Thanks Dave. The exact same thing happened to me bro. I hooked it up to my big Cheetah, and it was a mess. Had to get new intakes and seal it up a whole bunch.

Not only a life saver, it is a motor saver! Hahaha.

[JP374]

How could this work w/ a single???

[BBIII]

How could this work w/ a single???

all you would need to do is put the gauge and filler on one tube.

[dajogejr]

The tester I have has the filler and gauge on one line, using an iron splitter (3 way), one for the pump, one for the gauge, the last for the line to fill the motor.

[Laker]

Thx for the info!

[Asphalt330R]

Ok I have a question, and if I missed it some where in this post I'm sorry.

I want to build one of these for my 250R which uses a Rad valve. The I.D. of the intake boot is 1-3/4".

I went to Home Depot, I can't find that size pipe. All I found is either 1.5" or 2.0' PVC pipe.

Where can I get the pipe I need?

Has anyone built one of these for a 250R?

Thanks in advance