I am going to be doing my first leak-down test on my DT3 in the near future. I have read through all of the threads I can find on here and I think 
I have it down pretty well, just a couple of questions I need cleared up. Doing leak test because rpms runaway while slowing and high idle and it probably is just good to do as I have no idea how the bike was cared for in the past. 

1. What all do I need to disconnect from engine? from what I can find just autolube line.
2. Any suggestions on how to fit the tester in the spark plug hole?


 

Yes, runaway RMP and high idle are signs of a possible air leak.  You want to check the crank seals, intake/reed block, base gasket.  Do both a vacuum and pressure test.

Disconnect exhaust at cylinder and plug cylinder exhaust port.  Disconnect carburetor and block off intake.  You can plug oil injection port with an M6 screw and crush washer.

How to install?  What type of leak tester are you using?

I have exhaust and carb disconnected and am going to buy expandable plugs for those too. I am planning on going to the hardware store and buying some things to make one myself that goes into the spark plug hole.  need to find a pump to do vacuum? I haven't seen as much on those tests

though of a couple other questions I had. I read that you should take off clutch and stator cover when doing tests. If that is true will oil not come out... or do you empty the oil to test. 

Mityvac hand pump can do both vacuum and pressure, I think Harbor Freight sells a similar one but I've never used it.  

Drain the oil.  If tests are negative for leaks then you're fine.  If leaks then you need to find them and removal of the clutch may be necessary.

Edit:  Seems like my link above doesn't work right.  Here is the Mityvac I use (8500)

www.amazon.com/gp/product/B0002SQYUA/ref..._title?ie=UTF8&psc=1

Okay that’s good to know. Now I just need to drain the oil and get my tester set up. Anyone have any advice as to how to hook up to the spark plug hole? Find a fitting that screw in there is what I’m thinking right now

Hello bhepp15, great to read your thread re: leak down testing as  I have a similar posting running myself.  For the spark plug fitting do an internet search under LMA fittings.  They had an adapter for my cylinder head plug fitting which is an M14 x 1.25 (i.e.14mm diameter with a 1.25mm pitch). This adapted the hole to a 1/4" fitting which is an easy size to then find attachments for, such as a screw in barb fitting which is ideal for using with plastic piping.

Regarding draining oil etc. had you considered NOT removing the clutch cover because who's to say you have a RHS crank seal problem?  Unless you definitely know otherwise kick the test off and look firstly at the easy to fix leak sites such as the carb inlet etc.

Good luck with your testing and please keep the thread going as all info is useful to us 'first timers'. Andy.

Thanks Andy! I read your thread and was useful to me as well.  I am going to drain oil as I’m sure my bike would enjoy some new oil anyway. And thanks for the info on the spark hole, I already have a few 1/4 fitting in an online cart for what I’m planning on putting together so that will work perfectly! 

edit: could you not just use an m14 fitting with a barbed end instead of making it a two part process? 

Yes, if you can find a 14mm barb fitting that would work fine, I just could not find one anywhere on-line. Andy .

You can use a compression tester hose to pressurize, just unscrew the small one way valve on the end of it.