CG125 Exhaust Gasket: Remove and refitting

[veeeffarr]

Hi,

Parts came through for my exhaust today, just a couple of questions:

I can't see the old one inside the cylinder head, however the whole thing is covered in black shit (Carbon?) what's the best way to get it out, if indeed it is actually in there? (I don't want to take a screwdriver to the cylinder head and fuck it up).

There's a white rubber coating on both sides of the metal gasket, is this there to protect the surface prior to fitting (IE: should I remove it before fitting it, or is it part of the gasket?

Will I need a new plug in order to check if its still running lean , or will it show up on the existing one?

Anyone know how tight the head bolts should be? Tight as fuck to get a good gas seal, or tightish so I don't wreck the bolts?

Cheers,

Toby

https://s66.photobucket.com/albums/h277/th0r0n/ExhaustParts.jpg

[Rit]

Lo mate,
The inner of that gasket should be ribbed and I imagine you will see that in the exhaust port dispite all the crap. Its safe to lever that out with a screwdriver.

No need to scrape anything off the new gasket.

A new plug will be 2 quid and you can shove the old one in yer tool thingy on the bike as a spare

See piccy for engine torque values (aintcha got a manual?)

Have fun.
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[WavyGravy]

That looks like an asbestos type gasket, theyre either that or copper, either works, never heard of a rubber one!

I thought your old gasket was already out of the machine? if not your new one wont sit flush, have a poke around and see if the old gasket is visible, generally they dont fall out on their own as theyre designed to expand to fill any gaps when you tighten them up.

when you refit the exhaust dont tighten the rear bolt, the one that attaches to the swingarm, you want the exhaust to be loose while you tighten the front bolts ot else you'll be fighting something.

dont overtighten the bolts on the head, as youre crushing the gasket youll feel a resistance, you only need a small spanner to tighten it, like 4" ... not a big socket set, fit the whole thing together loosely in its right place and use your fingers to put the nuts on while holding everything tight with the other hand, then use your spanner alternately on each nut so you keep everything even, when you get to the stage where you need 'effort' to tighten youve tightened enough, take the bike for a spin and come back, wait for everything to cool down and nip up the nuts if they need doing.

oh yeah, dont forget the bolt on the swaingarm LOL
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1975 CB125s, 1991 GN250, 1990 Ducati Paso 906
"Don't wake him up - He's got insomnia - He's trying to sleep it off"

[stinkwheel]

As said, you'll be ok popping the old gasket out with a screwdriver (if there is one there at all). I usually carefully scrape the worst of the coke off the gasket surface of the head with an old screwdriver then finish it off with a scoosh of solvent (carb cleaner or similar, it doesn't have to be shiny, just more or less clean). You should be scraping away bits of dirt, not lumps of alloy so don't go at it like a bull in a china shop. You could gently use a small wire brush instead.

It is a fibre gasket. Fit it as-is.

New plug might be an idea, yours looked like it had had a rough time of it when you posted a picture.

Whne you have the nuts started off on the exhaust studs, tighten them up a bit at a time and alternately so the gasket is compressed down in a square fashion. Put lots of copper grease on the threads. 6-10ft/lb of torque (that is not all that tight so no standing on breaker-bars. Around as tight as you can make it using two straight fingers on your spanner about 6" away from the nut if you don't have a torque wrench and are bad at judging these things.)

Tradition has it that you then re-tighten the nuts at 5, 50 and 500 miles after fitting them because the gasket beds down and they go loose.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[veeeffarr]

Thanks guys, just what I needed.

No Copper Grease though, with LM do?

Ta

T

[stinkwheel]

It'll probably just burn off to be honest.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[mattish]

It really is worth using copper grease on the threads or you could end up snapping the studs next time you try to take it off. This happened to 2 out of 4 of my studs, but then they were 22/23years old

[veeeffarr]

Hmm bugger.

I will just keep it dry then, as they were when i removed the bolts

[veeeffarr]

I can see a copper colour ring in the cylinder head, nofuckingway it's coming out tho.

[stinkwheel]

Heat it up with a blowlamp then lever it out. If it is made of copper, the heat (lots of heat, glowing red ideally) will make it soft and easy to bend.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[veeeffarr]