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Post by scootnewb on May 9, 2018 18:07:56 GMT -5
Hello,
I am having some tuning issues and want to seal off any potential air leaks. Should I use gasket sealer between the plastic spacer and the head as well as the plastic manifold and the spacer? I have a gasket between the spacer and the head now. I just want to be sure everything is 'tight' and I don't want to use the wrong product that may cause problems if I have to (you know I will) remove it in the future.
Is there a better quality intake and spacer I could use. Right now I am using the stock manifold and spacer.
Thanks again.
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Post by scooterted on May 9, 2018 18:20:36 GMT -5
Rtv would be a solution. But most say they shouldnt be exposed to fuel. Have you sprayed carb cleaner on it while running to test for a vac leak?
*if you have a leak the idle will suddenly change when the leaking area is sprayed with carb cleaner.
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Post by scootnewb on May 9, 2018 18:31:45 GMT -5
Rtv would be a solution. But most say they shouldnt be exposed to fuel. Have you sprayed carb cleaner on it while running to test for a vac leak? *if you have a leak the idle will suddenly change when the leaking area is sprayed with carb cleaner. Yes. I have sprayed around and no change. Perhaps then some other sealant that can be exposed to fuel? |
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Post by FrankenMech on May 9, 2018 20:28:42 GMT -5
My manifold uses O-rings which seal by themselves, no sealant needed.
RTV will swell when exposed to fuel.
Permatex Aviation Form-a-gasket is hot fuel proof.
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Post by scootnewb on May 9, 2018 20:30:25 GMT -5
My manifold uses O-rings which seal by themselves, no sealant needed. RTV will swell when exposed to fuel. Permatex Aviation Form-a-gasket is hot fuel proof. Yes mine has the o-ring too. I am grasping at straws until the sun comes up and I can try different jets. |
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Post by FrankenMech on May 10, 2018 15:12:03 GMT -5
Don't put any sealant on the O-rings. Sometimes I will use a little oil or grease lube on them so they don't 'stick' to the surface.
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Post by GrumpyUnk on May 14, 2018 11:20:59 GMT -5
The O-ring can get flat with age & heat. I have removed them, fluffed to attempt getting them round again, and then re-installed. I don't have extra intake tubes on hand. I used a 'smear' of RTV, blue stuff by Permatex that is supposed to be usable near fuel/oil/heat. It was more of a wipe, to present a surface that would conform the irregularities of the cylinder head inlet surface. It is machined, but not as smooth as it might be, so a bit of seal, or a good, new O-ring is helpful.
It also might be helpful to see how well the 'biscuit' of bakelite(?) that is between the head and the plastic intake lines up with the intake port. I have one that separated, so could place it on the studs. It did not line up well, and, more or less, blocked a quarter of the intake port area. I used a Dremel type machine to ovalize the stud holes so I could align the block better with the intake port, and also did some grinding on the bakelite material. Dunno how prevalent this condition is, but it should improve breathing quite a bit.
tom
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Post by greginisn on May 14, 2018 23:36:58 GMT -5
I've forgotten what your air cleaner system is but if still the stock setup any major air leak in it can cause you problems. But then with the air leak a relatively constant thing tuning should solve the problem. A head scratcher for sure.
Greg
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Post by FrankenMech on May 15, 2018 2:22:30 GMT -5
I have purchased a half dozen or more of those bakelite spacers from different vendors and all of them were different. All supposedly for a 50cc engine. Different size center holes, different distances between the studs, different stud hole sizes, and different offsets between the center hole and studs. Some had round stud holes and others had ovals. I have no idea how a person could know which one fits what head and intake.
I did have to machine my head intake port, bakelite spacer, and intake manifold to fit each other properly using a small hole into a larger one at every transition. If you try to get the holes the same they will never line up at assembly and that will produce some nasty intake restrictions.
O-rings do take a set and are not really supposed to be reused but I do if they pass inspection. I do keep several different O-ring assortments around so I can usually find a replacement O-ring.
The bakelite spacer is supposed to reduce heat transfer from the head into that crappy rubber covered cast aluminum intake that always cracks.
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Post by scootnewb on May 16, 2018 7:42:26 GMT -5
I've forgotten what your air cleaner system is but if still the stock setup any major air leak in it can cause you problems. But then with the air leak a relatively constant thing tuning should solve the problem. A head scratcher for sure. Greg Thanks. I have a Uni filter. It looks like there wasn't an air leak around the manifold/spacer after all. Once I installed the right jets everything came together and I was able to tune it. Now it's time to move on to the brakes but so far it looks like a pain in the ass. XD |
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Post by greginisn on May 16, 2018 13:44:36 GMT -5
It's great that you have that sorted out what jet did you settle on?
With you perseverance you'll whip that braking problem too.
Good luck
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Post by scootnewb on May 16, 2018 15:14:09 GMT -5
Thanks.
96 main / 33 pilot
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