PA50II Exhaust Seal Ring

Hello everyone,

My PA50II is working well, save for the fact that the attached metal ring on the exhaust pipe that seals the pipe to the cylinder has broken off of the exhaust unit :( . My engine is now REALLY noisy and probably badly polluting the environment and causing me to lose power :( . Does anybody know if I would be able to weld some sort of metal ring onto the exhaust pipe to seal it to the cylinder? I don't want to leave it running like this for long; it's probably having some bad effect on my engine or the atmosphere or day soon I'll take it apart and post some pics of what I'm referring to, but in the mean time if you know of this and have ideas, let me know.

Keep ridin',


Re: PA50II Exhaust Seal Ring


Re: PA50II Exhaust Seal Ring

I'm sure there's _something_ you could do but i doubt there's a really easy way out. and stop riding for now, its too cold anyway.

Your cheapest, easiest best bet is to keep an eye out for stock pa50II exhuasts on ebay.

other than that go to your local hardware store or machine shop, tell them your problem and see if they want to help... sometiems there's really eccentric peopel that work there that won't rest until your problem is solved...

Re: PA50II Exhaust Seal Ring

Stephen R /

Too cold, blah, you must live somewhere warm! I'm willing to brave the weather to ride, so long as its not icy so I don't kill myself doing so. I talked around and it's probably not decreasing efficiency of the engine, right? If not, than the only real downside now is the noise pollution (I mean its not like the bike has a catalytic converter or anything!) but I can handle that! Thanks for your reply; I bet there is someone somewhere who'd want to help fix it.


Re: PA50II Exhaust Seal Ring

is exhuast fumes coming directly out of the engine? Put your hand down near where the exhuast bolts up to the cylinder and if you feel the exhuast fumes then it is NOT okay to ride your moped. You will have a loss of backpressure and you are probably running lean. buy a new exhuast.

Re: PA50II Exhaust Seal Ring

I've built exhaust pipes for my PA50II but i'm not exactly sure what you mean by a "ring".

The pipe has a small flare bent up at the end. And sliding loosely on that header pipe is a rectangular metal clamp piece with two holes for the bolts.

As originally manufactured, the clamping piece was slipped onto the header before final assembly and welding... or before they made the little flare on the end of the header.

Is the clamping piece or is the flared end of the tube what you mean by a ring?

Re: PA50II Exhaust Seal Ring

Stephen R / would be the flared end; the clamping piece is intact

Re: PA50II Exhaust Seal Ring

hmm.. my memory didn't serve me well. Now that i have a muffler in front of me i see there is a heavy metal "ring" between the flare and the clamp. Sorry about that.. Clue me in as to what's actually broken or missing.

If that heavy metal ring that pushes against the flare is broken, a new one can be easily made on a lathe.. i can supply the dimensions if yours is gone. However, that ring must somehow be slipped over the tube.. and that will involve cutting the tube and welding it back together.


So, for what it's worth..

Assuming that your flared end is gone, and that ring is not damaged, i will tell you what i think about repairing the flare.

You can flare the tube's end again unless a lot of metal has rusted away... You can do it with a small hammer a flat punch and a vice to hold the pipe. First heat the end of the tube red hot and let it cool slowly to soften the steel.

It might take an hour to hammer a new lip on the tube. Taking care to not collapse the tube in the vise, make the bend around the circumfrence at 90 degrees. The flare's outer edge extends only 1/8 inch (3mm) from the tube. Afterwards, grind or file it's edge to a nice round shape of the right outer diameter.. (1-1/8 inch diameter) (This outer diameter will fit into the thick metal ring's depression)

Then lightly file the face of the new flare flat, so it can mate flat against the exhaust gasket.

An alternative would be to weld a steel washer of appropriate inner and outer diameter to the very end of the header. I think that a perfect silver-solder job (using genuine high-silver solder... melting temp around 1400F) would hold since i have used hard-solder close to the exhaust port without failures.. The header gets hot but not red hot...

Since the header will be slightly shorter using the above methods, slight bends to the header tube and/or re-drilling or enlarging the holes in the muffler's attachment tabs will likely be needed.

So, another alternative would be to make a short, perhaps one-half inch long, flared tube and slide that into the old header tube. This will allow perfect adjustment so that no bending of the tube or re-drilling of muffler attachment bracket holes will be needed. Weld or hard-solder the short tube once it's proper placement has been determined.

Re: PA50II Exhaust Seal Ring

If you can't bend a new flare on it, maybe you could go to the Home Depot or local hardware and find some heat resistance gasket for a furnace. You could mount that in there somehow till you get the proper fix. Also what about that muffler bandage, that stuff they sell at automobile stores. You may be able to do something with that as a temporary fix. Just some ideas to cut down the noise and eliminate the fumes.

Re: PA50II Exhaust Seal Ring

Clamping pressure behind the flare is what holds the tube against the cylinder. Honda made a tight little assembly that leaves little room for error. Whatever repair is made has to be really strong.

but that patching stuff is really handy and works great for sealing holes. If the muffler can be solidly attached to the cylinder but leaks, stuffingg a bunch of that stuff around the area may be a good temporary fix for the exhaust leak.

Re: PA50II Exhaust Seal Ring

Stephen R /

What kind of patching stuff? Can I get it from a hardware store?


Re: PA50II Exhaust Seal Ring

There are various forms of muffler and exhaust pipe repair kits at auto parts stores. Get high-temp puttys for wood stove sealing and repair at a hardware store.

Both types harden like a rock.. parts cannot move or vibrate without cracking the repair. It should muffle the sound for a little while but don't expect miracles.

Re: PA50II Exhaust Seal Ring

Tom Rainwater /

Hardware or Walmart for some JB Weld. Mix it up and wait twenty-four hours for it to harden completely. It will not break loose or burn up from high temp.

JB Weld I swear by it for any exhaust problem.

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