Trying to perform my first leakdown test and cant figure it out.

[bigbuilder]

I am working on my sons blaster. It is burning transmission fluid.

I have a gasket set now and I pulled off the clutch cover and clutch.

I rigged up a leak down tester and a pressure guage.. Hooked it into the intake, plugged the exhaust .

But I cant get it to build any pressure at all. I have sprayed everything

I have watched all the videos.

Am I missing blocking something off? Or do I have to put the clutch cover back on?

Any help is appreciated.

 

[Larry's Shee]

You mention nothing about spraying it with soapy water. That’s how you find the leaks.

Right off the bat you might as well replace BOTH crank seals because guaranteed the right one is leaking. Be sure to seal the collar and key to crank when assembling. NO SILICONE!! 3Bond or Yamabond only.

Now you can start putting air to it.
NEVER apply more than 7psi.
It must hold that for 7 minutes

 

[bigbuilder]

Good Morning, Thank you very much for the reply. Sorry, yes I have sprayed it many times with soapy water but can get any pressure at all. If my cranks seal is sucking trans fluid in would that seal leak enough that I wouldnt see any pressure build?

Thank you for the tip on the 3 bond. I didnt know that.

I have the factory manual but I dont find it as good as some others I have used.

I have never done crank seals before. Only a couple of top ends on other machines.

 

[bigbuilder]

Just doing some more reading. Is there a good video out there that shows how to do both crank seals and applying the 3 bond?

 

[Larry's Shee]

Take your pick
https://m.youtube.com/results?search_query=crank+seal+replacement+2+stroke

 

[Larry's Shee]

Clean inside of collar and crank with brake cleaner. Smear a bit of sealer inside of it and on key, install. I do both only because the banshee has a tendency to leak at the key, that way I don’t have to remember which is which.

What are you using to pump it? If it’s leaking so much it won’t pressurize you should be able to hear it leaking

 

[bigbuilder]

Hi Larry. Thanks again for all the help.

I will watch the video with my son.

I am was using a small hand pump little squeeze ball. Then I switched to a bike pump for a few pumps. Neither did anything . I have a 6 psi guage on it also. There is a black tube coming out of the top of the bottom case ( clutch side) what is that for?

 

[CycleTech]

Crankcase breather. If you have air escaping (from leakdown test) at that tube then your cases are damaged at the crank chamber. Thats also another way to pull in trans fluid while running. Just some food for thought

 

[Larry's Shee]

Problem is he already has the clutch cover off

 

[Larry's Shee]

You haven’t removed the gear and collar from the end of the crank have you?

 

[CycleTech]

You haven’t removed the gear and collar from the end of the crank have you?

Good chance this is his original problem if not the crank seal itself.

 

[bigbuilder]

Hi, Sorry for the late reply. I wasnt able to get to a computer. I havnt removed the gear and collar yet form crank. Just the clutch pack at this point. I was going to work on it tonight. Is there something I need to be careful of when taking the gear off?

 

[bigbuilder]

I was just reviewing the video link but I dont see a clutch side crank seal replacement. Is there one out there just for the blaster or a detailed written description? After watching some of the videos ( dirtbikes mostly) the talk about some special tools ?

 

[Larry's Shee]

No clue about special tools, I just use one or two screws run into seal. Never watched any videos. Only thing is you have to seal collar and key way to shaft , I use 3bond. And I lube the seal with grease. All 2stroke seals are the same. Don’t drive it past flush with case. Try your own search, if you’re not satisfied.

 

[CycleTech]

No clue about special tools, I just use one or two screws run into seal. Never watched any videos. Only thing is you have to seal collar and key way to shaft , I use 3bond. And I lube the seal with grease. All 2stroke seals are the same. Don’t drive it past flush with case. Try your own search, if you’re not satisfied.

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