Can I remove the stuck Cylinder Head from CB250N Engine? Sid the Scrambler Build Part 7

Working to remove the head from by CB250 engine takes far more effort then expected, and huge thanks for recent comments.

[@brocksommerfield6897]

Thanks mate, for the screwdriver trick that saved my hours of pain and struggles with my 2000 Honda xr250r engine with a stuck cylinder.

[@centauri8820]

Thanks bud, used a rubber mallet and a piece of wood, worked like a charm

[@bikahjoeUK]

Love this video, your honest and humble approach is very refreshing. I've come straight to this one without seeing any of your others yet, as I did a search for removing stuck cylinder heads. I have a 1979 Suzuki GS 750 with the same problem. Got two engines (one in and one spare) and both have piston issues. You have inspired me to have a go myself at unsticking the notoriously difficult cylinder head and getting to the root of the problem. Cheers!

[@RyansGarageUK]

Thank you. I am learning as i go and im certainly not going everything "correctly" but enjoying the experience. I'd encourage you to give it a go if you possibly can.

[@chrisbagley8104]

Hello again. Just a few comments on removing the cylinder barrel. Never use crow bars or anything steel (or wood!) to remove aluminium heads, barrels etc. It will only cause damage. Your comment "Victory" it may have been so, but a Pyrrhic victory nevertheless. Do you have a Honda parts book? If not go to Classic Honda site and get one. A parts book will show every single nut, bolt, screw, seal on the entire bike and where they go, most useful. The problem of stuck cylinder heads and barrels or any thing aluminium is caused by Honda's love of steel dowels in contact with aluminium. This causes electrolytic corrosion which in time will almost weld the whole lot together. I rebuilt a CB750 F2 DOHC engine a few years ago it took three days to get the head off and another two days to get the barrels off. It's rather shutting the stable door after the horse is gone, but next time you are refitting barrels and pistons, oil the pistons, rings and the bores. It makes them easier to fit and acts as lubricant on the first start up. Oil down the plug holes after fitting the head is not best practice. Lowering the barrels down with the piston skirts resting on the casing is again not best practice use wood strips to support the pistons. Damage to the skirts will be avoided. Stuff some rag into the crankcase below the pistons until all rings are in the cylinders. Should you brake a ring guess where the bits will end up?

[@RyansGarageUK]

Hi Chris, thank you for your comprehensive suggestions. I think that you make excellent points, and I had not thought of using wooden blocks to support the pistons, I did oil the pistons before installing but failed to show it. I have a Haynes manual but not the workshop manuals I'll investigate the cost for future reference. May I please ask, how did you eventually release your head in this similar situation? Ryan.

[@chrisbagley8104]

@@RyansGarageUK Hi, Firstly you didn't say "Victory" but win, sorry about that! The wood should be square in section, so it keeps the pistons vertical. Not workshop manual, spares book. I have one for my 250n, one advantage is one can order by part number, not the whatsit that fits in the thingamy! The problem I had with the 750 was the design of the engine has the head studs in the centre and outboard towards 1 & 4 cylinders and directly behind the front wheel so the two front studs get all the road rubbish, salt and wherever thrown straight on them. They were corroded so much it was as good as welded.. I used hard wood (oak) wedges chamfered to a sharp edge, heat from a full size blow torch. petrol mixed with diesel oil (not with the blow torch at the same time!) With the wedges and the heat the head raised 15cms it stopped moving and refused to move any more. The outer studs, with a little persuasion came out leaving only the 4 centre studs in place. I then came up with the idea of getting some studding to fit the threads of the holes from which the outer studs had been removed, some penny washers and nuts to fit the new studding. Cut the studding to length, threaded it through the head. When it reached the gap between head and barrels threaded on the penny washers (to spread the load on the ally head and barrel. Wound on the nuts, locked the lower nuts on the barrel to secure the studs and wound up the nuts to push up the head. This on all the outer stud holes, this push to. the whole head up against the corrosion. Then poured the petrol/diesel mix down the studs. This to keep even pressure on the head to stop warping. Wound up the nuts as tight as I dared and went to bed. Next morning repeat the above, I found the nuts would turn several turns then stop. The idea with the petrol/diesel mix is the petrol carries the diesel into the smallest possible space, evaporates then then leaves the diesel act as a lubricant. Repeat, repeat repeat. It surrendered in the end. Use the same on the barrels too. One has to be patient, it took a long time and I used a lot of oak wedges too. When I finally lifted off the barrels, a cup of tea for celebration was taken!

[@RyansGarageUK]

@@chrisbagley8104 wow, that was clearly a well fought battle and a well deserved victory.. I think there would be aspects of this tale I could learn from. Thank you for sharing your experience. Ryan

[@motorcyclerescuer]

Only way to learn is to do it. Great job.

[@RyansGarageUK]

Thanks Charlie.

[@derekdingwall]

Your making progress Ryan and learning along the way ,me too🤔😀👍

[@RyansGarageUK]

Thank you Derek. Still lots and lots to learn.

[@robertadams4415]

Ryan you can also use Stanley razor blades wedge them between the cylinders and the case

[@RyansGarageUK]

Thanks Robert, not thought of that before. 👍🏻

[@kevincrowley6991]

No penetrating oil and soft hammers surely before trying to use the levers

[@RyansGarageUK]

Hi Kevin, the video may not make it obvious, but I did try gentle methods for many hours before the levers were used.

[@Reel_Deviant]

Might a rubber mallet have been a choice in removing the cylinder sleeves with impact?

[@InTheShedUK]

I was shouting at the screen... Don't hit it there! Don't hit it there! The corner is the weakest point, if you are going to hit it at all the strongest point where the fin support webbing is. Personally I use a rawhide or nylon mallet, side impact, the jarring should eventually free it.

[@RyansGarageUK]

Hi, I wish I had heard you a little earlier. but I will learn the hard way. Sorry. Ryan

[@stephenwalsh8184]

🏍👍

[@RyansGarageUK]

Thanks.