Thanks Greg, the pics are spot on. I think you might want to take a good look inside your engine for metal. G is right about the rockers. When you pull the crank web off, try to check and clean as much of the bearing surfaces as you can for debris and give it all a good wash out. You can dress out small wear marks and scuffing on the cam and rockers with a very smooth stone, but go nice and easy with it. Any bad rockers will need replacement of course, but they are available. Like G said, use the ones without the hole in the sliding face if you can.
I still don't like that sleeve/bush thing in the oil supply hole.
Earlier in the thread you spoke about the base gasket and it being thin/narrow at the back of the sleeve/bush. You asked if the part of the gasket on the inner case side was really needed.
If it's not there, oil will be pumped back into the cases through the gap. I put a very thin smear of sealer around the oil hole to make sure that there is no leak there. Be careful not to use too much and don't get it anywhere near the oil supply hole.
Cheers, Brian.
Rebuilt engine seized
Hi Brian
I think everyone had concerns about that tube in the oil hole. I am now thinking that they put it in to try and stop leakage from the base gasket but the reason it was leaking is that they had blocked the oil feed to the RHS bearing with sealant ....... is this consistent? I think my comments about the thin gasket were misleading. What I was trying to ask relates to the fact that because it is a 350 the liner is wider, this means that there is a gap in the aluminium in the casing which the gasket would normally rest on adjacent to the cam chain well. I assume the liner will stop any oil flow. There is some metal above the gasket (though not a lot ) but nothing below it so my choice was to have a thin bit of gasket not fully supported or just cut that part of the gasket away but then you could argue you would weaken the gasket by not having a full circle around the liner. On reflection I think better to cut away as there must be a risk the unsupported piece of gasket would fall into the crankcase. I will get a photo if not clear. Cheers Greg
Greg
I can show you some clean, standard cases today. G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
Having seen Graham's standard cases the gasket is not fully supported all the way round because there are cut outs towards the front and centre but it is the same for std and 350 conversion the only difference being that the gasket will be thinner on the 350 because of the larger liner but I guess there is no need for concern.
I have now had my crank rebuilt.
Many thanks to Graham for providing the necessary repair parts. It turned out that it is actually a cb72 crank but this does not appear to be of much concern. There was good news in that the rest of the crank was undamaged. However the builder found that both the centre section was too wide (by about 1mm) and that it was not exactly at 180 degrees. His view was that the seizure was likely due to this causing the bearing to rub and overheat. I am not totally sure, as the bearing position is pegged I assume if the crank was wide there would be pressure on the cage/bearing but if too wide then the pin would not engage in the bearing and you could not fit the cases together?    Greg
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