1JZSupra
Active Member
I wanted to do a leak-down test after having a discussion with a buddy of mine and seeing some of the issues he was having. My 1st gen has about 23500 miles on the clock and I've had to reshim at least three times already. During this time I went ahead and pulled the valve cover as it had been at least 7k miles since I had checked all the valve clearances. Go figure that every single one is grossly too tight. After getting a good result from the leak-down test I was happy I wouldn't have to pull the motor apart. A 9% leak-down is a great result. Using the compressed air method I took the time to go ahead and since a set of titanium retainers. This was a bit of a challenge and I would not recommend doing this if you are new to working on engines.....
This is a common practice in the import car world that I have done in the past so I was fair confident I could make it work. I used a wrench and some other tools to lock the crank at TDC so it wouldn't shift when I applied pressure into the cylinders. One thing to note! When the piston is at TDC it is impossible to drop a valve! The piston to valve clearance is just too small to allow the valve to drop low enough.
Here is a short video I made. Again, do this at your own risk and be careful with your keepers. The exhaust side took some effort, if you have large hands you more than likely won't be able to change them out the way I did.
(3) ktm 390 duke titanium retainers installed without pulling the head - YouTube
I also went ahead and powder coated my valve cover. I have all the required equipment at home so it was fairly straightforward. Should you decide to do the same it should be noted that the baffle plate under the valve cover will need to be removed. There is a fiber gasket that will need to be replaced. One thing that I was surprised about we the amount of moisture that was behind this gasket. On top of that, you can tell that the gasket, over time, wasn't holding very well which seems to allow for that moisture to drip back into the head. There is NO replacement for this gasket so you will need to make yourself a new one. ENSURE YOU USE LOCKTIGHT on the baffle bolts, you do not want those dropping out. On a side note, for being 23k+ miles the internals look great and pretty much brand new still. Motul 300V oil is great!.
This is a common practice in the import car world that I have done in the past so I was fair confident I could make it work. I used a wrench and some other tools to lock the crank at TDC so it wouldn't shift when I applied pressure into the cylinders. One thing to note! When the piston is at TDC it is impossible to drop a valve! The piston to valve clearance is just too small to allow the valve to drop low enough.
Here is a short video I made. Again, do this at your own risk and be careful with your keepers. The exhaust side took some effort, if you have large hands you more than likely won't be able to change them out the way I did.
(3) ktm 390 duke titanium retainers installed without pulling the head - YouTube
I also went ahead and powder coated my valve cover. I have all the required equipment at home so it was fairly straightforward. Should you decide to do the same it should be noted that the baffle plate under the valve cover will need to be removed. There is a fiber gasket that will need to be replaced. One thing that I was surprised about we the amount of moisture that was behind this gasket. On top of that, you can tell that the gasket, over time, wasn't holding very well which seems to allow for that moisture to drip back into the head. There is NO replacement for this gasket so you will need to make yourself a new one. ENSURE YOU USE LOCKTIGHT on the baffle bolts, you do not want those dropping out. On a side note, for being 23k+ miles the internals look great and pretty much brand new still. Motul 300V oil is great!.
