Forums 🚥 PIT STOP 🔧 Hyosung Technical Help Help identifying mystery pipe!!

This topic contains 4 replies, has 2 voices, and was last updated by  Madcoop 2 months ago.

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  • #2611

    Madcoop
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    Apr 22, 2019

    New engine turned up today….woohoo!! The joy was short lived though because of the shock discovery of a mangled exhaust outlet, chipped surrounding fins and butchered exhaust stud. Leaving me only around 7mm of thread to play with! Subsequently it has now had to go to the doctor to have an extraction done with the correct tools for the job. Fingers crossed it comes out cleanly.

    Down to business though. Apart from the above problem the engine looks pretty good, and turns over with no nasty noises etc. Haven’t checked the clearances yet, but I will when she comes home. One thing that jumped out straight away is the presence of a pipe (i assume to be vacuum) coming out of the rear cylinder.

    On my old engine this pipe is not present and the port is blanked off.

    I have checked through both the workshop manuals and the parts catalogues and come up with nothing. It doesn’t even appear as part of the engine rebuild process in the workshop manual, and I don’t see it listed anywhere in the parts catalogue.

    Can anyone tell me what this pipe is for and where it should go? Also, as my original engine is blanked, is it just a case of getting a blanking plate and gasket for the port? Where would I get such a thing?

    Please excuse my ignorance if this is a total newbie question, but as I mentioned in my intro I am completely new to bikes, so this one is a bit of a mystery. All I can think is that it could be to run a fuel pump or the like.

    Thanks in advance.

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  • #2612

    ♠️ MARCEL
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    @mf448kxn6
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    Hey.

    The metal pipe that is at the rear cylinder or front is for fake emissions.
    It steals piston energy & air from airbox to fake readings for emissions. (Euro3 nonsense!)

    Not to worry. It is a good thing yours didnt.  Early hyos didnt have it.

    Here is what you do. Find a fat 10mm hose(thereabouts) .
    Cut 1 inch of it.  Get 2 metal clamps.
    Put a fat bolt in one end or a metal bung/plug.
    Shove the blocked hose to the metal pipe thats on engine.

    Its best to do this before running it!  Cant have pistons suck debris in.

    // Meditation doesn't mean you have to sit still....

  • #2615

    Madcoop
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    @madcoop
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    Aaahh, it all becomes clear. I have read about some emmision stuff from NZ, where they delete it. Makes sense now. Thank you.

    She’s out of surgery now and I’m glad to say it all went well. I just need to worry about cleaning up the copper ring round the exhaust exit. It’s well mashed to the extent that I think there may have been a drill used too!

    That ring isn’t per chance a changeable gasket is it? That would make life so much easier.

    Thanks for making sense of that for me Marcel. 😉  Nice easy delete too. I hate when I am faced with something I don’t understand.

  • #2630

    ♠️ MARCEL
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    You could take a look at the link below & browse the last photo , you will see a 2d diagram and what the rings actually look like:

    That copper ring has to go lol, think the person who sent you the motor did a rush job trying to undo pipes off it.  It would ride rough if its leaking hot gases out , and we don’t want any debris going in there!

    https://hyoriders.club/exhaust-gasket-studs-nut-hyosung/

    // Meditation doesn't mean you have to sit still....

  • #2631

    Madcoop
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    @madcoop
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    GT125R (carby)
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    That copper ring has to go lol

    Thanks again Marcel. I had actually turned to the parts catalogue and seen that it was indeed a gasket. Just wasn’t sure, because this one is welded in!! The fella I bought it from broke his hand the day before it was due to be collected. It still had the rusty old downpipe on it and had contacted me to ask what to do. My answer was to tell him to do the best he could, but if need be just send it as was. He ended up asking a neighbour to help removing the pipe and having spoken with him, I think he was quite annoyed himself with the resulting damage. He still should really have told me before it was on my doorstep.

    No harm done though, the damage isn’t too drastic and should clean up well enough. New gasket should get me a good seal once I deburr the outlet. I’ve been painting parts all day, so I haven’t really got to the engine, but I’ll knock out the work on that over the next week or so. In an effort to make the engine look a bit fresher, he has blown over the cylinder heads with grey primer. That is going to need fixing with some matt black,  but thankfully he was quite accurate with the primer, and applied it using card to shield things that didnt need paint. Not too much overspray given its been a rattle can job, but I think I’ll be putting the matt on with an airbrush for accuracy.

    Don’t get me wrong, I’m not going for split new cleanliness on this bike, but a bit tidying up doesn’t go astray along the way. Innfact, it would be rude not too.

    Thanks again for your help Marcel, and keep an eye out for my next uncertain moment…lol

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