Changing head gasket on the EN 125 for the first time

[GrumpyGuts]

I warned you this would happen

Went out today and bought torque wrench, thread lock compound, gasket dressing, engine oil and an allen wrench. It's finally time to change the head gasket.

I will start off by stating that this is the first time I've ever attempted this...on a four stroke

Armed with plenty of bacci, Relentless, the Oracle what is called Haynes and my left arm in a cast, it begins!

1) Like I said, plenty of stimulants

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08153631.jpg

2) Drained the oil from the bike. New engine oil purchased. Note the milk carton with the old oil which now also contains a screw bit after dropping the bugger

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08153226.jpg

3) Removed the seat and fuel tank bolt (only one bolt as the other has bloody sheared off)

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08153234.jpg

4) Removed fuel tank and stored elsewhere (heavy!)

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08153334.jpg

5) Removed battery for safety

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08153615.jpg

6) Removed sprocket cover (access to the alternator cover)

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08165758.jpg

7) Removed spark plug cap and plug itself

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08165127.jpg

8) Removed carb from the inlet manifold and placed slightly to the left, tacho cable, both cylinder head covers, tacho drive assembly screw and cylinder head steady

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08162423.jpg

9) Removed exhaust and frame earth

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08164333.jpg

10) FINALLY removed tacho drive after much swearing. I have damaged it (oops) but it was in there! Stored safely as to not dry up.

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08173138.jpg

11) Removed the inlet and exhaust valve inspection covers

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08175742.jpg

12) I then went about setting the engine to TDC (Top dead centre). I did this by removing the inspection nut on the crank case, removing the alternator cover and rotating the alternator rotor until the markers matched up (not pictured)

13) Removed the 10 cylinder head bolts in order according to Haynes to evenly distribute the force of removing them (taken before valve covers were removed) and making sure I do not disturb the two rocker bolts.

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08174956.jpg

This is the sheet of paper I've used to number each bolt. Very handy technique...

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08181548.jpg

14) Removed rocker cover. This was a c*nt to remove and required several soft taps with a mallet.

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08181454.jpg

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08181504.jpg

15) Observing the mess

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08181600.jpg

16) Removed cam chain tensioner bolt and tensioner

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08183047.jpg

17) Removed cam sprocket bolts

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08190400.jpg

18) Removed cam shaft, cam sprocket, that circlip thingy and inserted a rod to prevent the chain falling down the tunnel

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08190810.jpg

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-08190816.jpg

I then started undoing the head bolts, but I've hit a brick wall. ONE screw won't budge. There are 4 nuts on top of the cover and two on the left side of the engine retaining the cylinder head cover. One of the side screws won't move. The nut should stop halfway so it would begin to unscrew the rod but it was come all the way off, leaving the rod hanging there like a bellend.

Will update tomorrow as it has now gone dark. I've coated the thread in compound and will try to remove it tomorrow.


____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[GrumpyGuts]

Ummm....

https://i47.tinypic.com/iyprw4.jpg
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[nowhere.elysium]

Why are you doing this?
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[karthead]

The first time i've ever done something to a 4-stroke was a head gasket change except on a car... Good luck!

[GrumpyGuts]

[GrumpyGuts]

Update:

https://i47.tinypic.com/34fbbz9.jpg

That's Peter the Piston. Peter looks a bit worn and choked of carbon. Replacing Peter, along with his rings with a kit ordered from Wemoto.

Cylinder didn't look too bad. No deep scratches, marks or scorch marks. Just cleaned and lightly oiled it, which includes the rest of the barrel which was coated in oil.

https://i50.tinypic.com/332oy8p.jpg

That is the old head gasket...it was literally a thin piece of metal with no gasket material so no wonder oil was splashing out!

New base gasket ordered, too. Knowing Wemoto my stuff should be here tomorrow, so I'll post the pictures tomorrrow
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[lukamon]

er... you know that head gaskets ARE just a piece of metal dont you? there is no "gasket material" unless you count an o-ring around the oil passage.

also, cancel the piston order. i would reuse that piston without a second thought, and youll have to run in a new one.

interesting, never seen a head / rocker cover where the rockers come away with it. kinda makes sense though, makes everything else easier to get at. make sure. you you re-do your valve clearances after putting it back together!

Luke.
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killa wrote: Im an ass man myself

[orac]

that piston is fine, chuck it back in without removing any of the carbon (it will smoke like a bitch if yo do).

you have a very small but normal amount of thrust wear and some carbon, which is normal, any excess carbon will be from burning some oil that had leaked from the head gasket and wil self remove once you got everything back together and running well.

a new piston and ring are complete waste of money from looking at what you are holding.
____________________
Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[GrumpyGuts]

Oh..nevermind. I've asked a few other people and they said to renew it. Oh well its a good opportunity to learn
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[Frost]

New piston and rings can never hurt. Put some loctite on the cam chain sprocket bolts as if they come loose you're fucked
Cleaning the shit out of all mating surface helps when it come to torquing bolts up. A smear of hylomar doesn't hurt either but i guess it depends on how fussy & rich you're feeling.
Remember shit loves sticking to oily bits and a few well placed bits of grit can cause a lot of wear so it's probably with cleaning then re-oiling the moving bits as they go back together.
The two most important things are timing and valve clearances (how are the valves?) when it comes to putting it all together again as it might run like shit, or not run for very long depending on how badly you cock it up

[Frost]

Also replace the exhaust bolts and copper grease the shit out of the threads. You won't regret it.

[GrumpyGuts]

Well what Ive done is bought new engine oil and will be lubing all the moving parts as well as the tank. Ive bought thread lock compound for some internal bolts (according to the haynes manual) and grease for placing gaskets, along with gasket dressing. No new exhaust bolts as they are pretty much new anyway and an exhaust gasket as somehow it's missing. Would I need to change my oil again to run in the new rings? Say, after 300 miles? Or just take it easy for a little while?

As mentioned, the valve clearances will be slackened before torqueing the head bolts and re-adjusted (walked 6 miles to the shop for a fricking feeler gauge) and cam chain tensioner slackened and refitted after cam chain is in place)
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[_Iain_]

Winning. I like threads like this.


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Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[Frost]

The rings will need to bed in which some people recommend riding very slowly for aaaages and gradually building up the revs, others thrash the bike hard to bed them in. I've no idea which is right but for the sake of caution i'd take it slower than normal for a few hundred miles.
Badly fitting rings cause increased smoke and oil consumption. Yours certainly won't be bad but they won't be at their best right away either so increased oil consumption and an oiled spark plug would be things to watch out for short term.

Make sure you do the head bolts down in a criss-cross order to squash the gasket evenly.

Exhaust gaskets would be a good idea.

[Islander]

Don't forget to gap the rings before you fit them and make sure that the gaps on the three rings are spaces at 120 degrees to each other.

[GrumpyGuts]

Well the piston came with the rings attached so no problem there.

The barrel and head have been installed but I'm stuck on the camshaft/cam chain assembly.

The manual is so unclear that I'm stuck. I fit the C clip into the groove and then put the sprocket onto the camshaft flange, but I can't seem to get the chain looped properly. I can get the chain on the sprocket and the sprocket locating pin through that little hole (and then making sure the flange and the markings line up) but the chain tension is loose.

Basically (whilst crank is at TDC) when I move the cam shaft, the crank doesn't move aswell because the chain is not taut. I can wobble the chain where the alternator rotor is and I do not know if it supposed to do that until you put the rocker cover back on. I fit the cam chain tensioner but it doesn't seem to taut the chain so when you rotate the alternator the camshaft does not move.

Any ideas what I'm doing wrong?
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[Frost]

You sure the tensioner is working okay?
I assume it's the usual spring and ratchet type. Have you reset it? does it move freely?

[GrumpyGuts]

When I removed the tensioner blade, I mis read the manual and took this out when I should have taken out the tensioner assembley. I took that out way later (and is still currently out).

I replaced both the guide and tensioner blades before the camshaft. Manual then says to put in the camshaft, sprocket and chain whilst the sprocket and camshaft flange markings line up with the cylinder head. That is when my chain is floppy and not connecting properly. The manual says to install the camshaft tensioner to take all the free play.

The tensioner has a lock nut in the middle. When you remove that a spring pops out and you have the push rod. I can't see a screw in there and I believe that tension has not been changed because I didn't remove this first.
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[Frost]

Usually you remove the bolt from the end of it, take the spring out and move the tensioner all the way back in. You then put it in the engine and bolt it in place before you put the spring and bolt back which then tensions the chain.

[GrumpyGuts]

The engine is still in the frame.

I took out the blade before I took out the tensioner, so I'm going to reverse this (even though it's wrong) so see if the chain tauts. I remember when I removed the blade before the tensioner the chain slackened, so if I install the tensioner first then the blade it should tighten
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[Frost]

Not sure i really get it. The pensioner should push on the blade to tension the chain. The blade should be installed first, then the outer tensioner with the ratchet reset, then the inner bit of the tensioner which will then push the blade and tension the chain.

https://farm4.static.flickr.com/3590/3300854477_493c204412.jpg

https://cog-online.org/clubportal/images/clubimages/1328/webpages/Techguide/camchaintensioner-stock2.JPG

[GrumpyGuts]

That's what I thought, but when i installed the tensioner it did bugger all. Here's some pics (sorry about the quality, taken with a potato)

First two are of the tensioner. One without the spring and one with.

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-11231455.jpg

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-11231520.jpg

This is my engine now

https://i77.photobucket.com/albums/j69/willyrobbie/SAM_0194.jpg

This is the bottom of the blade. I can wiggle this chain very freely and you can see the blade next to it

https://i77.photobucket.com/albums/j69/willyrobbie/SAM_0190.jpg

Now this is the slack I have

https://i77.photobucket.com/albums/j69/willyrobbie/SAM_0193.jpg
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[GrumpyGuts]

Right, engine sorted, sounds good. Turns out that the cam chain dislodged itself from the bottom sprocket so I had to borrow a pulley to remove the alternator and fix it back on.

Start up was really a tense moment, it took me ages to get the timing right, but after a few spluttered starts the engine runs like a beauty. Pics to follow with the new piston.

Wheel turns out to be bent after the accident and my rear brake does not work so that will have to be sorted ASAP!
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My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[dungbug]

[GrumpyGuts]

Well got some pictures off my phone, it's all done. Really the only thing I need to do is check valve clearances.

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-11141503_zps21be948b.jpg

The piston on the left is the old one with the obviously new one on the right. A lot of difference there!

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-11142628_zps762c22b0.jpg

The new piston installed with...

https://i77.photobucket.com/albums/j69/willyrobbie/2012-09-11144754_zpsfe7b0b5c.jpg

The new head gasket!

If anyone is thinking of doing this, don't make the mistake I did by taking out the tensioner blade before the cam chain tensioner assembly. Moving the chain after caused it to dislodge off the bottom sprocket and you will end up needing a flywheel pulley to remove that!

Here is a Youtube clip of the bike with the engine running. I'm selling the bike now, cost me too much money and to be honest there's a mint condition CG 125 waiting for me, so I'm prepared to cut my losses
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My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012