Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Mike_Berkshire on April 26, 2024, 06:13:32 PM
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Following the successful (final) removal of the seized oil filter bolt and the seized engine hanger I have got the engine out and on the workbench. Sump, breather cover, cam end covers removed. Rocker cover/assembly screws and bolts all removed thanks to the impact driver and JIS bits recommended by this forum. However, the rocker cover/assembly wont lift off. I have given it a few taps with the soft mallet and checked for hidden bolts but I cant see anything I have missed. There is a clear gap at the front of the engine between the cover and the head but at the back (intake side) there is no gap at all. It looks as if there are a couple of locating dowels on the back edge which if steel may have corroded and stuck fast. Is there a bolt/screw I may have missed and what are the thoughts about the locating dowels sticking; does this happen and if so is there a remedy? I have attached an aerial view in case there is something obvious to the experts. Many thanks. Mike
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2 solid dowels there, you can see the top of them, soak with penetrating oil and leave it with overnight. If still stuck, gentle diffused heat will help. Don't forget to remove the all the tappets before trying to remove the rocker cover.
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2 solid dowels there, you can see the top of them, soak with penetrating oil and leave it with overnight. If still stuck, gentle diffused heat will help. Don't forget to remove the all the tappets before trying to remove the rocker cover.
Thanks Julie. I will douse them in penetrating oil and leave overnight as suggested. Its probably a good idea to put the bolts back in to keep the castings flush? I will see how things are tomorrow morning.
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Im assuming that the dowels are designed to be retained in the head and not in the rocker housing? Giving the top end of the dowel a few taps with a blunt punch might hep free off some of the corrosion?
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Mine was fairly solid, might be worth tapping it back down where it is sligjhtly raised. I found my big rubber mallet worked making sure I tapped it all round including some upper blows on the intake side.
I also sprayed WD40 type stuff all around the dealing area.
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Mine was fairly solid, might be worth tapping it back down where it is sligjhtly raised. I found my big rubber mallet worked making sure I tapped it all round including some upper blows on the intake side.
I also sprayed WD40 type stuff all around the dealing area.
Thanks Ted. I have just given it another good squirting and a firmer tapping with a plastic headed mallet to no avail. I havent tried tapping upwards from the intake side; i will try that tomorrow morning after an overnight soak. Where did you bash it upwards on the intake side?
I can slide a polished paint scraper around between the castings to the right hand dowel but not the left hand one so I guess its seized on the left one. Im assuming the dowels are supposed to be locked into the head as opposed to the rocker housing?
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The dowels aren't locked to either part Mike, they are totally removable. It's just the corrosion that's making them feel locked at the moment.
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The dowels aren't locked to either part Mike, they are totally removable. It's just the corrosion that's making them feel locked at the moment.
Thanks Julie. Does that mean that they can be tapped out to free them or are they waisted?
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Mine was fairly solid, might be worth tapping it back down where it is sligjhtly raised. I found my big rubber mallet worked making sure I tapped it all round including some upper blows on the intake side.
I also sprayed WD40 type stuff all around the dealing area.
Thanks Ted. I have just given it another good squirting and a firmer tapping with a plastic headed mallet to no avail. I havent tried tapping upwards from the intake side; i will try that tomorrow morning after an overnight soak. Where did you bash it upwards on the intake side?
I can slide a polished paint scraper around between the castings to the right hand dowel but not the left hand one so I guess its seized on the left one. Im assuming the dowels are supposed to be locked into the head as opposed to the rocker housing?
I would tap it down on the side where you can get the scraper in AFTER squirting in releasing fluid then I tap it on the inlets first as close as possible to the head working along the four intakes - I used quite a big soft but weighty rubber mallet that I bought years ago at the centre Isle in Aldi. If you have a lead shot type mallet even better as there is no rebound. Also squirt plenty of releasing fluid down the dowel areas and bolt holes. A tap from the left and right side might help. If the front side is slightly raised keep it back down working more on the rear and sides. Cups of tea in between tapping sessions and light or medium blows should work - plenty of decent releasing fluid not standard WD4o helps. I used some releasing fluid that car technicians use not bog standard WD40.
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Yes they sieze for a passtime, not sure if they can go all the way through either hole as never tried it, the always move eventually
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Maybe remove the tappets and refit the covers minus o rings to give you another handy place to knock. Or if want replace them ( very cheap ) partially screw them in leaving a lip to drive against taking care to protect the valve cover edge. Haven’t tried this but it might be worth investigating.
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Thanks all. Im pleased to report that with the dawn of a new (rainy) day there has been another victory in the shed. What did the trick was using a blunt ended punch and using it to tap the end of the dowels using a metal hammer to get a nice sharp impact; not much force was needed and this was obviously sufficient to crack the bond between the steel dowel and the aluminium. Look out for the next posts asking for help and advice getting the head off. Im gong to leave it for a while before the next step having squirted releasing oil onto the head bolts. Thanks again for the support.
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Well done Mike always rewarding when you overcome such obstacles - the Cylinder head was a swine to remove on my 400.
As you have the engine out it should be easier to get releasing fluid everywhere before you start.
I have found you need plenty of time for such penetrants to soak through not a quick process.
It might be a consideration to look at ways you might be able to get gravity to help so that the weight of the head itself helps.
Just wondered is there is a way to support the engine upside down on wooden blocks or similar?
It's slightly different subject area - my carb sliders took well over 24 hours of petrol & other solvents to work in a closed container, all four of my carbs were stuck solid. The last one did not yield until three or four days believe it or not. The good news is new they eventually freed off without damage of any kind.
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Its been a pretty good morning so far. Head and barrels now removed and time for a rest and some tea. Just a couple of worries along the way: 1) I only have 11 head bolt washers, not 12 so where is the 12th, was there ever a 12th? ( I have used an inspection lamp to look down the cam chain tunnel and I cant see anything in there, I have given the head a good shake and it hasnt fallen out. 2) the screwdriver slot on the cam chain tensioner adjuster screw is stripped out/snapped off. Waiting for my son to come round later this morning to help remove the forks.
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Going well - I always enjoy the dismantling stage - goes without saying taking photos before stripping down and more detailed photos at various stages of dismantling helps later on.
It's amazing how easy it is to forget what way round an item fits when it's months later before you start assembling.
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The washers stick in the head recesses but if really missing are still available new.
On the adjuster is the thread stripped all the way down or just at the end? Honda should never have put that slot in there it gets abused.
New pattern ones are available but expensive and dont often come up used in good order any more.
I MAY have a used one but it wont be cheap
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The washers stick in the head recesses but if really missing are still available new.
On the adjuster is the thread stripped all the way down or just at the end? Honda should never have put that slot in there it gets abused.
New pattern ones are available but expensive and dont often come up used in good order any more.
I MAY have a used one but it wont be cheap
Thanks Bryan. The thread isnt stripped its the slot that has broken away; theres only half the slot. I have a mate who is a very ingenious fellow with a plethora of lathes, welding equipment and goodness only knows what else. I will see what he can devise but if I draw a blank I'll let you know.
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Are we talking here about the captive type stud/bolt that is normally part of the tensioner blade - not available as a separate part? Is your tensioner blade in otherwise good condition.
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Its been a pretty good morning so far. Head and barrels now removed and time for a rest and some tea. Just a couple of worries along the way: 1) I only have 11 head bolt washers, not 12 so where is the 12th, was there ever a 12th? ( I have used an inspection lamp to look down the cam chain tunnel and I cant see anything in there, I have given the head a good shake and it hasnt fallen out. 2) the screwdriver slot on the cam chain tensioner adjuster screw is stripped out/snapped off. Waiting for my son to come round later this morning to help remove the forks.
found on mine that you need a magnet to tell if washer is stuck to head on some of the less accessable ones
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Are we talking here about the captive type stud/bolt that is normally part of the tensioner blade - not available as a separate part? Is your tensioner blade in otherwise good condition.
The tensioner blade and mechanism assembly looks to me to be in good condition. It is just the head of the screw that goes through the 10mm nut with the little gear bit on the end. Where the outer part of the locking screw should have a slot it has had too much force applied with a screwdriver and one side of the slotted part for the screwdriver has sheared off.
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found on mine that you need a magnet to tell if washer is stuck to head on some of the less accessable ones
A top tip Martin; I'll try that, thanks!
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As long as the nut screws on leave it alone as you dont need that slot
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As long as the nut screws on leave it alone as you dont need that slot
That’s good to know Bryan. How do I switch it from slack to tensioned when I rebuild the engine?
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You dont ever use the slot anyway, when building before fitting cam stick fingers down tunnel, push slipper to carbs and hold whilst nipping up locknut then just undo when built and holding pressure on kickstart, nipping up whilst holding pressure.
Check the tensioner fold over tabs are crimped over tight to hold theteeth on the bolt in mesh with the rack, people forcing the screw slot in the false idea that this will tension the chain is what damages the meshing in the first place
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I assumed the end slot was was for a stubby crewdriver to stop the bolt from turning as you nipped up or released the lock nut.
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Surely is Ted otherwise it would turn as the nut tensions up
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It never has in all the years i been doing them, BUT i do make sure the nut runs free
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Agree Bryan mine didn’t move so I wondered what the point of the slot is.