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Post by tsimi on Apr 29, 2016 23:44:26 GMT -5
So today was the moment of truth. I got the right air valve and installed the big reed block with paper gasket only and intake. Then I attached the leak tester and pumped air into it. It doesn't hold air at all. The moment air goes in it comes out right away. Then I started to put my ear over the intake and near the paper gasket of the reed block but no sound of air leaking. Then I checked the CVT side crank seal and I am not sure but I think it leaks a tiny bit but not on the outer lib but on the inner lib where it touches the crank. Then I also checked the stator side seal, same there. It doesn't leak from the outer lib but from the inner lib where the crank touches. So I called the bike shop guy and asked him if that is normal and he said not all crank seals are there to vacuum seal sometimes they are there to avoid dust and dirt from going into the bearing from the outside. Right now I don't know what to think... if what he says is true then I just wasted $30 for a leak tester that was not needed. LoL The good thing is the CVT seal was not leaking air from the spot that I thought it would so I guess it sits good. Next week I will get a complete gear assembly from a friend of mine and he owns a 4t press so we will install the necessary bearings and gears and I just continue to build the engine as far I can and hope that it will run/start when finished.
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Post by oldgeek on Apr 30, 2016 0:00:58 GMT -5
Soapy water (bubbles) will tell you where you are loosing air.
For our motors, the crank seals and the intake MUST NOT have air leaks, or tuning will be a constantly moving target.
The gearbox seals are as he describes. They keep dirt out and gear oil in, but there is not any pressure or vacuum present.
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Jog-Mania
Apr 30, 2016 0:08:03 GMT -5
via mobile
Post by tsimi on Apr 30, 2016 0:08:03 GMT -5
I will do a leak test on my red jog that has the stock crank and stock seals still inside see what happens.
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Post by oldgeek on Apr 30, 2016 0:29:36 GMT -5
In case you didn't already have it, here is a link about building and using a leak down testerPersonally, I would not mess with your red jog motor. Stick with the one you are building, conquer it and learn from it. I have destroyed 3 or 4 seals one after another, screwing them up trying to get them in right. Sometimes it krappy seals, sometimes its bad luck, some I just screwed up. But I get it sealed up eventually!
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Post by spaz12 on Apr 30, 2016 0:34:37 GMT -5
6 pounds of air for 3 minutes. That's the standard test. When I was messing with the little prebug that I got, that has 4 or 5 thousand miles, it had a barely noticeable loss after 30 minutes. Most aren't like that but still, that puppy needs to hold air.
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Post by tsimi on Apr 30, 2016 1:14:21 GMT -5
To make a leak test on my red jog shouldn't be all to difficult. I want to compare and see if the same issue occurs. All seals are brand new stock Yamaha I have no reason to believe that they are faulty. If they would leak from the outer lip I could use some motoseal or any sealant but if the leak through the inner lip well... what then? Buy stock Yamaha seals until I get non faulty ones? I don't believe that stock Yamaha products are china style 1 good out of 10. And the seals ain't cheap either.
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Post by spaz12 on Apr 30, 2016 3:04:59 GMT -5
Are you sure it's not the tester or what you used to block off the exhaust? Have you tried the soapy water yet? I'd spray everything including your tester.
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Post by tsimi on Apr 30, 2016 5:01:32 GMT -5
Will do spaz12Tomorrow I will spray all over soap water and see where the leak(s) is/are.
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Post by Lucass2T on Apr 30, 2016 5:26:04 GMT -5
I don't believe that stock Yamaha products are china style 1 good out of 10. Hahahaha! It's true!
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Post by tsimi on Apr 30, 2016 6:10:33 GMT -5
spaz12I didn't do the leak test with soap water yet but I looks like the exhaust port cover I made is not holding at all. The hissing sound I was hearing came not from the seal but from the exhaust port. I flipped the engine upside-down and could hear it better plus a bit of oil that was inside the engine came out of the exhaust port. Before I can do another test tomorrow with soap water I have to find a better solution to plug the exhaust port.
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Post by ryan_ott on Apr 30, 2016 8:39:36 GMT -5
Just use sealant (rtv, motoseal, etc) to seal it up with the flange you made. Let it setup then retest. Or you could put a oring under it when you tighten it down.
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Post by spaz12 on Apr 30, 2016 11:54:43 GMT -5
P.s. Wouldn't matter if the tool leaked because you're using a Schrader valve
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Jog-Mania
Apr 30, 2016 18:37:46 GMT -5
via mobile
Post by tsimi on Apr 30, 2016 18:37:46 GMT -5
A what valve?
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Post by Raizer on Apr 30, 2016 19:37:04 GMT -5
That type of tyre valve is a Schrader valve.
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Post by tsimi on Apr 30, 2016 19:45:36 GMT -5
Changed to this valve yesterday. Does a better job of keeping the air inside.
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