Exhaust How Do I Seal An Exhaust Slip-Fit Connection?

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5-7HEAVEN

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I have a Tanaka 47R 2.8 hp racing engine on my Diamondback bike. After recently installing a Tanaka three-piece expansion pipe, I am plagued with leaks at three separate slip-fit connections. The head pipe bolts nicely onto the cylinder, so that's not a problem with its flange gasket. This 29mm pipe then slip-connects to the neck of the fat chamber. This leak is 24" below my chin. Exhaust gas leaks there and burns my eyes, so I bought a VERSACHEM high temperature exhaust bandage wrap kit(for cars). It's an epoxy/fiberglas mesh/aluminum tape combination I used to wrap and seal the large slip-fit pipe below my chin. At the pipe's exit, there's a 15mm slip-fit which I also wrapped and sealed.

The last slip-fit is from the silencer's tip to the OEM muffler. There is a slip-fit adaptor w/retaining spring, but it's designed to "bottom out" onto the silencer. This leaves no overlap to seal. I just know it'll be a waste of time and materials to use the fiberglas/aluminum tape wrap. I also bought a CAR-GO high temperature exhaust repair kit. It looks like liquid in a bottle that turns hard like epoxy. This MIGHT work, but not sure.

Does anyone have any suggestions how to seal this connection? The outside diameter of the flange adaptor is mm. Maybe a high-temperature oil seal like something from an old VW pushrod tube would fit and work.

Any suggestions?

Here's the Tanaka engine and the three-piece pipe:
http://wikiscootia.wikidot.com/tanaka-47r
 
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Or you could braze it yourself. Get a torch, a block of metal, and some solder. takes 5 minutes.

well, you would need an acetylene torch (not a propane torch because it will not get hot enough),and some brazing rod with a flux outer core.
not sure why you would need a block of metal tho???
heat the 2 peices of pipe at the joint until the brazing rod will melt when you touc it to the surface. it's just like soldering, except you are using brass and much higher heat.

normally tho, slip fit pipes are held together with springs and the 2 pipes are usually a pretty tight fit. each peice of pipe should have a couple of hooks on them, you stretch the springs and hook them onto the hools on the pipes.
but, these springs are usually very stiff and hard to stretch without a special tool.
brazing would be the fastest, easiest and best way to make the joint leak proof.
 
well, you would need an acetylene torch (not a propane torch because it will not get hot enough),and some brazing rod with a flux outer core.
not sure why you would need a block of metal tho???
heat the 2 peices of pipe at the joint until the brazing rod will melt when you touc it to the surface. it's just like soldering, except you are using brass and much higher heat.

normally tho, slip fit pipes are held together with springs and the 2 pipes are usually a pretty tight fit. each peice of pipe should have a couple of hooks on them, you stretch the springs and hook them onto the hools on the pipes.
but, these springs are usually very stiff and hard to stretch without a special tool.
brazing would be the fastest, easiest and best way to make the joint leak proof.

Slip-fit connections are tight fit, but not air tight. This is good enough for rear-mounted gopeds, but not for center-mounted engine mounts where exhaust leaks are nauseous to the rider. Besides, since this pipe was made for gopeds, the mounting and fitment is a compromise. Pipe fittings are maybe 45* off, so the springs' hooks don't line up. They hook up, though and do their job for a rear-mounted engine, but not for front-mounted drive setup..

Brazing is the best way, but not fastest or easiest or cheapest. Labor charges are outrageous for machine shops. I'll need to find a competent welder at good rate. I'm going to wait until the other slip-fit repairs fail. Hindsight is always 20/20, or I would have had it welded to begin with. The exhaust repair kit was cheaper than the high cost of welding, so I had to try the kit first.
 
Most large towns have a muffler shop of some sort, They have much experience brazing and welding thin wall pipe and probably will charge a lot less than a specialized welder. You can rent a torch and tanks to braze it yourself, but for such a small job the muffler shop will be cheaper. An independant shop, rather than a large chain like Midas or Monroe will probably be more open to small jobs.
 
Would RTV red accomplish the leak fix effectively?
It would provide any strength, but should seal it.
Good luck
rc
 
TRV red? Okay, might try that.

SBP uses short pieces of silicon exhaust tubing to seal their expansion pipe's slip-fit connection. Since the Tanaka engine's head pipe is much larger than HT engine pipe, I'll need to search for larger-diameter silicon pieces. A piece of 1/2" silicon exhaust from davesmotors might be good for the endbleed's connection.:unsure:
 
well, you would need an acetylene torch (not a propane torch because it will not get hot enough),and some brazing rod with a flux outer core.
not sure why you would need a block of metal tho???
heat the 2 peices of pipe at the joint until the brazing rod will melt when you touc it to the surface. it's just like soldering, except you are using brass and much higher heat.

normally tho, slip fit pipes are held together with springs and the 2 pipes are usually a pretty tight fit. each peice of pipe should have a couple of hooks on them, you stretch the springs and hook them onto the hools on the pipes.
but, these springs are usually very stiff and hard to stretch without a special tool.
brazing would be the fastest, easiest and best way to make the joint leak proof.

Just how i do it. I used to seal holes in gas tanks. I had a metal block/bar i would heat up, then use regular old solder touch the heated block near the hole, and melt it in to close the holes. Did it with radiators too.

Not sure about exhaust as i would just use a welder normally, but you could technically just use a soldering iron and some solder. But I am not sure about if the exhuast owuld get hot enough to remelt the solder.
 
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