Head gasket installation

iceteanolemon · Mar 2, 2013

I had placed my head gasket on but did not anneal it. The bike ran great but the gasket leaked a little and now I am fed up with that. I took the head off again and would like to reinstall it after annealing it. So I have the gasket annealed no but I want to know what you guys are using for gasket sealant. I used the copper spray last time and it didn't seem to matter with that.

So what's the best goop to use on the head gasket? Or should I even use anything?

Thanks for any info you guys can provide.

eezeetoo · Mar 3, 2013

Using solid copper gaskets, I have used no goop, except for a ring of Loctite 515 Form-a-gasket around pushrod holes etc,
Dave

Hobot · Mar 3, 2013

If they leak they leak and not much can be applied that can really stifle it, but good rings and good PVC and 50 wt oil. Traditionally the metalic sealers like Copper Coat or just copper or silver spray paints are common. I had about as much success with Hylomar as just dry annealed. If I missed a re-torque in first 1000 miles or so, like d/t a trip then leak can develop and not stop till annealed and reset keeping ahead of re-torque routine.

pommie john · Mar 3, 2013

I use a coat of silver paint from an ordinary automotive rattle can.

johnm · Mar 3, 2013

If you didnt anneal the copper gasket then thats your main problem in my opinion.

I use only copper gaskets and the following has always worked for me.

First make sure it fits properly, a good close fit around the studs and bolts.

Make sure the oil drain down return hole is clear.

Make sure the gasket does not extend into the push rod tunnels. Some do and will rub against the push rods.

The head and barrel sealing surfaces should be clean and in good condition.

Anneal the gasket to cherry red. You will see lots and lots of coments about plunging it into water. I do put my ones into water because this cleans it. If there is any material left on the gasket then clean it off but do not work harden the gasket.

I spray with copper spray.

Make sure all the bolts, stud and nut threads are clean and I put some WD40 or similar on them.

Torque the fasteners to the correct torque. If you are really keen you can use a spring balance to determine the torque on the nuts which can only be tightened with a ring spanner.

Start the bike and run it for 5 minutes.

Then turn it off and leave overnight until stone cold.

Then loosen and retorque the fasteners and ride the bike gently for say 15 km.

Then it cool down again and repeat the retorquing process.

Repeat the retorquing at say 500 km and then you should be all good.

John

grandpaul · Mar 3, 2013

Are you sure your cylinder deck and head surface are both true?

mike996 · Mar 3, 2013

"Are you sure your cylinder deck and head surface are both true?"

+1

iceteanolemon · Mar 3, 2013

johnm said:
If you didnt anneal the copper gasket then thats your main problem in my opinion.

I use only copper gaskets and the following has always worked for me.

First make sure it fits properly, a good close fit around the studs and bolts.

Make sure the oil drain down return hole is clear.

Make sure the gasket does not extend into the push rod tunnels. Some do and will rub against the push rods.

The head and barrel sealing surfaces should be clean and in good condition.

Anneal the gasket to cherry red. You will see lots and lots of coments about plunging it into water. I do put my ones into water because this cleans it. If there is any material left on the gasket then clean it off but do not work harden the gasket.

I spray with copper spray.

Make sure all the bolts, stud and nut threads are clean and I put some WD40 or similar on them.

Torque the fasteners to the correct torque. If you are really keen you can use a spring balance to determine the torque on the nuts which can only be tightened with a ring spanner.

Start the bike and run it for 5 minutes.

Then turn it off and leave overnight until stone cold.

Then loosen and retorque the fasteners and ride the bike gently for say 15 km.

Then it cool down again and repeat the retorquing process.

Repeat the retorquing at say 500 km and then you should be all good.

John

Thanks for the write up. I appreciate it. I was looking for some detailed follow through so as I could see if there are key points I may have missed.

As for the deck being true or not I need to check this. I will check this today. Hopefully its not all tweaked.

xbacksideslider · Mar 3, 2013

After annealing, use whatever goop sparingly on the cylinder surface, lay a ring of very fine silk thread around each push rod hole. Place gasket, also gooped sparingly. Lay a second ring on the top of the gasket. Place head, also gooped sparingly.

Aerosol works best for spare and uniform thickness. Alternatively, I use those "acid brushes," made of bristle and tin plate; I use a scissors to cut the bristles short and stiff, then sparingly apply goop from tube/can to the sealing surface with the brush.

iceteanolemon · Mar 3, 2013

xback, thanks for the tips. I already installed it though this morning and did not do the silk loops this time. Last time I did it but didn't anneal. Ugh.

So this time I used the copper spray and annealed it. After annealing the gasket I let it air dry and then used wire bush to clean it off. When I sprayed the gasket I allowed it to sit for 20 minutes before installing it. It really is a bitch getting the head on without touching the fresh copper spray. I managed to do it though so that is good.

Although I have not ridden the bike farther than the end of the street and back I did allow it to idle for a while when I was adjusting carburetor and tinkering. So far there is no sign of leakage. I have since re-torqued only the exhaust nuts.

Last time when I installed it without annealing the gasket I noticed a small bubbling of copper seal from between the head and cyl during warm idle. I could see it if I shined a flashlight between the fins. This time I see no bubbling.

I am not getting my hopes up till I put at least 10 miles on it.

no fun without pics.

Cheers,

Hobot · Mar 4, 2013

coldbrewwithcitrus, your photo is one of the most interesting informative and thought provoking I've seen of combustion behavior when compared to my own and others with and w/o various faults.

Ya can see where the gases escaped. This would likely work harden the low spot so retorque could not smash it down tight again. I am now pensive of reusing a blown by gasket as work hammered a bit thinner in spots annealing don't fill in. There are degree's of gasket trauma so may not happen to you. But don't give it a chance, re nip each cool down or close but especially after first good heating up and throttling up. If ya baby it easing up to 65 ish on the level then even poor blowing by gaskets don't hardly weep I've found. Go faster and pressure can show up as outside mess. Don't forget all the other case fasteners too.

Mr. Singh says it a good sign where combustion surfaces are clean as implies good turbulence combusting all carbon in that area. I wondered where a groove or two might work for our heads, yours implies two oblique ones between the exh valve and plug aimed from rim to plug each about 1/2" long. What would make one crown thin carbon all over and the other more crusty but with good clear areas?

JRD · Mar 4, 2013

This shows that oil is not as good as gas when used to fuel the engine .You cannot conclude anything about combustion with oil burnt all over the place and a blown head gasket .

johnm · Mar 4, 2013

" Although I have not ridden the bike farther than the end of the street and back I did allow it to idle for a while when I was adjusting carburetor and tinkering. So far there is no sign of leakage. I have since re-torqued only the exhaust nuts. "

Ok ??

What happened to let it run for 5 minutes turn it off and let it cool overnight before retorquing the head fastener nuts and bolts ?

The exhaust nuts are something else again.

If you didnt let it cool and then retorque you have missed out the most important step of all.

Looking at the photos yes there are signs of leakage and blow by in 3 maybe 4 places including between the cylinders.

How far had the bike travelled ? The right hand cylinder looks like it is sucking oil either from the drain down hole or valve guides.

Both cylinders look very black - either very rich and maybe some oil thrown in.

Hopefully the blow bye didnt go on too long because you may have eroded the head a bit in those areas.

A give away for a leaking head gasket is a squeaking noise on first start up from cold.

acotrel · Mar 4, 2013

I also anneal the gasket by heating to cherrry red then plunging into cold water. I've never used sealant, only ever high melting point grease smeared on both sides of the gasket. As for the exhaust nuts ,I use stepped stubs and Yamaha two stroke exhaust compression gasket rings which the stubs screw down onto in the head. The pipes have sleeves welded to them which fit over the stubs , and I use springs and tabs to hold the pipes back against the step on the stubs. I'm very careful to make sure there are no internal steps in the exhaust set-up. The stubs sometimes come loose , but have never done any damage to the threads . I don't tighten them too much - just enough to keep the system gas tight . When the bike is running , the slip joints allow the exhaust to bounce backwards and forwards a little bit. If the pipes are rigidly mounted the threads in the head must suffer.

johnm · Mar 4, 2013

Im looking at the photos again and thinking you really need to check all the basics

- Valves and valve guides. What is the clearance , are the seals in good condition

- what are you using for an engine breather

- is the oil drain down from the head blocked

- check your ignition timing.

- are your carbs worn. Dont start with the main jets. They only apply to the last 25 % of throttle opening at most.

grandpaul · Mar 4, 2013

Already put it back together but didn't check that the head & cylinder mating faces are flat and true?

Prepare to do it all over again...

iceteanolemon · Mar 4, 2013

I think the gasket wasn't sealing and oil was getting in there from the oil galley or pushrods tubes. I hope the heads not leakin oil through the valve guides, I just had the head redone a little bit ago.

The ignition is electronic and I set it using a gauge in the cyl to get as close to tdc as possible.

I did notice the leaks by looking at the cyl.

I will retorque this morning and give it another run.

Carbs are new

Oil drain from head is clear

I'm hoping this was a bad gasket install and that's it.

I'm using a comstock breather

johnm · Mar 4, 2013

iceteanolemon said:
I think the gasket wasn't sealing and oil was getting in there from the oil galley or pushrods tubes. I hope the heads not leakin oil through the valve guides, I just had the head redone a little bit ago.

The ignition is electronic and I set it using a gauge in the cyl to get as close to tdc as possible.

I did notice the leaks by looking at the cyl.

I will retorque this morning and give it another run.

Carbs are new

Oil drain from head is clear

I'm hoping this was a bad gasket install and that's it.

I'm using a comstock breather

OK this all sounds pretty good.

But I dont quite understand " I set it using a gauge in the cyl to get as close to tdc as possible"

Do you mean you checked top dead centre against the degree guage in the primary chain case inspection cover and then strobed the igniton to the recomended ignition timing from the ignition manufactor - Boyer Pazon etc. (Something like 30 degree BTDC depending on the advance curve).

Did you assemble the head? Has it got seals on the inlet valves? Did you have new valve guides fitted and if so was it done by a good shop because you can get cracks and oil down the outside of the guides as well.

Carbs and breather sound all good.

xbacksideslider · Mar 4, 2013

The piston crowns do look oily but then maybe the engine didn't get up to temperature when last run?
Re-torque and get her going, spring is here! If she burns or leaks a little oil, OK so be it, top her off and ride.
PM me when you want to ride.

Beautiful shot of the top end of your engine; Jim's carbs look good too.

Hobot · Mar 4, 2013

Coke don't look that excessive to me.
If head fairly new not likely intake guides weeping, just pretty ordinary carbon richness we need to run before gets full heated. A hillbilly de-coking method it run engine to temp then use plant water sprayer into carb while blipping and blipping for quite a few minutes till the clouds of greyish turn more whitish. If ya stall it no big deal just re start and rev more or spray a bit less. Water steam on carbon turns it to dry dust that can brush off or blow off.

Head gasket installation

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