Leak test question

[fischer550]

I bought the blowsion engine block off plates to make leak down testing easier.

Can you use regular gaskets to do it, or do you need to use some silicone or something?

My intake is leaking like crazy with a brand new gasket under the blockoff plate.

 

[Yami-Rider]

I always use rubber, so idk if paper will work. You can use an old tire tube as a gasket, done that many times when I make my own block off plates.

 

[fischer550]

I'm just using regular yamaha gaskets.

 

[DAG]

If you need some rubber seals I die cut them

 

[Kny21]

Got an old bike inner tube? I just used carpet tape to hold cut up tubes to my diy block off plates.

 

[fischer550]

Shouldnt the leak test work with normal gaskets?

Won't ther be an air leak with normal gaskets if the same gaskets dont pass the leak test?

 

[Roseand]

On intake gaskets if you're having trouble with leaks use a little Yamabond/1211. Otherwise I've found that "high tack" made by permatex works awesome. Get it in the spray can and coat your gasket.

Sent from my SM-G920V using Tapatalk

 

[Yami-Rider]

I've never seen someone try to use a paper gasket, probabaly a reason for that and no, the intake is under vacuum, not 8psi of pressure, so it most likely wouldn't be leaking there.

Just use a piece of rubber and be done with it.

 

[Roseand]

Leak test with a block off plate and some form of rubber gasket. Using a cut up tire tube works otherwise @DAG cuts some nicer seals.
When you block off that intake and pressure test it you're more concerned about finding leaks through the crank seals or crankcase halves sealing surface, base gasket, etc. Those are a little more difficult to fix than an intake leak. If you're intake is leaking it's an easy fix. You shouldn't have to remove intake gaskets often(not the carb gaskets) so a little bit of a sealant or gasket sealer like i mentioned helps. I prefer the permatex high tack since it doesn't make a mess.

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[fischer550]

Ok I made a rubber gasket out of a bike tube, worked great.

I retested, and I have a leak in the cases just right of the front crank seal, not the seal itself, its a small area.

Can I just use 5200 and apply it to the leaky area, or do I have to take apart the case?

 

[Yami-Rider]

To fix right, take cases apart and use yama-bond.

 

[Captain PegLeg]

Flip the motor upside down and remove the bottom case and reseal. No need to remove and tear down top end.

 

[yamanube]

I used gaskets on my leakdown test, covered them in grease so I didn't have to worry about scraping them off of my cases later.

 

[fischer550]

Flip the motor upside down and remove the bottom case and reseal. No need to remove and tear down top end.

I did just this, worked great! Is it possible to replace crank seals this way?

 

[fischer550]

I used gaskets on my leakdown test, covered them in grease so I didn't have to worry about scraping them off of my cases later.

This is what I did, covered in grease too. My intake gasket leaks like this for the leak test. Exhaust held air

 

[Yami-Rider]

Yes, you can slip your crank seals out while your at it.