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Discussion Starter · #1 ·
Hi folks,

I recently had a very small oil trickle from where the header pipe meets the cylinder on my sx 125. I replaced the o rings in the header pipe and sealed with a thin layer of permatex copper high temp gasket sealer which stopped the oil run, but after running it today for a bit there still seems to be a slight bit of spooge around where the pipe meets the cylinder. Is this a problem and any other fixes? Just very annoying. When fitting the pipe it does not seem to fit exactly flush, and was like this when purchased, same when refitting. Any advice to sort would be appreciated cheers.
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Discussion Starter · #2 ·
The right spring seems to be smaller than the left side.. not sure if this may cause an issue. The spooge appears on the right hand side of where the pipe meets the cylinder
 

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Pipe has had impact and is a bit tweaked. Either need a new one or spend some time getting some mapp gas on it and try go tweak it back to where it was. Springs should be same size afaik on all the smokers, but on the 125 it looks like, from the pic, that they need to be differing lengths.
 

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Discussion Starter · #4 ·
Maybe has been impacted previously, but when I take it off the pipe looks fine at the cylinder end. I thought the new rings and sealant would do the trick, and has improved it, but still a very small amount noticed today. Just annoying! 😊 most recent pic below after running it today. The oil leak no longer runs, but still visible around the bottom right of the header
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What year is the bike? Manifolds wear. Bigger o rings won’t save it if worn.

small bores should be oily though. They need it for the revs. They don’t like any weak commitment riding. It has to on it.
 

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Discussion Starter · #8 ·
Not too familiar with jetting, still learning. I do know the boy who owned before raced it, and I am just getting back into motocross so not hammering the revs as hard as it is probably jetted for.. but not exactly riding it slowly either! 😊 Not sure if that’s an issue. Is it easy enough to check jetting?
 

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The pipe mounting points can put stress on the pipe alignment and pull the header out of alignment in the head.
Try this:
Remove the silencer and both (all) the front pipe mounting bolts.
Loosen the bolts holding the rubber bushes for the front pipe mounts so that they are clear of the pipe.
Remove the front pipe, clean the pipe to manifold surfaces, fit new original o rings and seal with gasket gobbo.

With just the springs holding the front pipe in place, check that it is sitting square onto the manifold and doesn't rock when you push it side to side. New springs are cheap enough so change them anyway. 10 year old springs will have given by now.

Line up the front pipe mountings and tighten them finger tight. Keep checking that the pipe stays square in the head.
Add the silencer and tighten the bolts from the front, working back to the silencer.

If you can do all that without the pipe shifting in the head, all should be good. If you can't, you should easily see where the pipe is bent and you can work at pulling it back into shape.
I had to do it with a 125 EXC as the pipes are pretty flimsy. I used an old hammer shaft in a vice and used that to bend the pipe against. Plenty of heat and steady pressure will do it. Don't jerk at the pipe or you can easily bugger it.

Good luck.
 

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Be very careful with the amount of RTV silicone there, it might end up somewhere in the engine.
Mate bought a 2019 tpi that wasn't running properly, only to find a "line" of red silicone in the crank pressure sensor hose (the hose is located behind the cylinder)
 

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Discussion Starter · #12 ·
That pic was taken just as the header was put back on. Only a thin layer around the o rings but pushed a little out when fitting. Wiped it off afterwards.. noted though. :) all removed and cleaned waiting to try and fit back on again. Just waiting on a smaller torx key to adjust the awkward front mount as my torx sockets are too big to loosen it. In a very awkward place (pic below) and adjustable spanner is no use for it. Hopefully should fix the issue following the advice above 👍
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Discussion Starter · #15 ·
Wasn’t sure if they should be there, and more than likely not helping with the issue? I wonder if it was due to ill fitting pipe vibrating with previous owner. Just trying to cover all bases. The pipe does not fit flush, although does not seem to be bent, and takes a bit of serious adjustment when seated to sit as close as possible to flush.
 

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Discussion Starter · #17 ·
Just waiting to get that off with a small torx key and hopefully adjust to the correct angle, any issues I will just replace. Got my fingers crossed. Thanks everyone for your help, been a god send 👍
 

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Discussion Starter · #19 ·
It takes a good bit of muscle to get it sitting kind of flush.. still not perfect so more than likely 😩 It seems like a bolt on.. hopefully I can source one easy enough. Maybe just best to replace the front pipe too. It’s a doma pipe that came with it
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