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Intake leak test question

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Intake leak test question


Post by txpan49 » Sat Apr 29, 2006 5:34 am

I am using Cotten's Virtual Indian intake leak test method and have some questions. My available tools include a rubber bathtub stopper and an air compressor hose with the air compressor set on 15 lbs. I put the stopper in the intake and insert the compressor hose in a hole I put in the stopper. The stopper fits pretty snug (like it would in a bath drain) and I squeeze the air trigger. The plug pops out pretty rigirously. I made a retainer to hold the plug in while I get the full air stream going and it will not stay in place and I see no bubbles from my flanges.
If the air intake can pressure up enough to blow this kind of stopper out continously do you think I have a good leak test?

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Re: Intake leak test question


Post by Jack_Hester » Sat Apr 29, 2006 8:22 pm

Back off to about 10 or 12 psi, and try again. Leak bubbles will show up at a lower pressure, too. You need to be able to watch it for a bit.


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Re: Intake leak test question


Post by mbskeam » Sat Apr 29, 2006 11:16 pm

try a hose clamp or 2, around the whole stopper and manifold.....
but A.C. gages at 15psi are very inaccurate at low readings


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Re: Intake leak test question


Post by Cotten » Sun Apr 30, 2006 4:48 pm

15 psi is actually overkill.
14.7 is equivalent to total vacuum at sealevel, and I doubt that vacuum ever approaches two/thirds of that.
But overkill is nice when you are doing a diagnostic.

The important thing is that the supply is constant. Airbottles and handpumps don't cut it.

I find soft rubber stoppers (common laboratory #9 for an OHV, I think)will stay in at 10-12 psi, and letting the system sit under pressure for a minute or two is important to discern the very tiniest leaks, which manifest themselves as little zits or even hanging tits of foam.
Folks without three hands end up making plates for convenience, especially if they do bikes regularly.

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