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British Bikes / Re: New to this old bike lark
« on: September 30, 2014, 12:43:42 PM »
NO engine SHOULD leak oil, but many old ones DO, whether this is just a case of it being old or poor assembly or there being some damage to joint faces or seals or in some cases, there just being moving parts which are open to atmosphere such as open valve gear or primary drives that you can't do much about, is a point for investigation. They certainly SHOULD NOT piss oil everywhere.
Certainly with modern gasket sealants and technology it should be possible to get most engines pretty oiltight - it's not always easy though and sometimes takes a bit of thought and ingenuity to get there! Basically it's all about good assembly - the first thing is to make sure that mating faces are flat and undamaged. Use a sheet of fine wet and dry paper on a surface plate or sheet of glass to flat them down. You will find that most old engines are put together with greased thin paper gaskets between faces which can be dispensed with and a good liquid gasket sealant such as ThreeBond 1104/1194/1184 used in its place. Always use sparingly on dry faces though and be especially careful if oil passages run through the joint. Watch it though when the original gasket is a thick one because there will probably be a reason for this such as clearance being required for something to work. In this case either assembling with the faces cleaned off with a bit of thinners on a rag and an new, bone dry gasket or a bit of sealant smeared on either side of it will do the job. Where shafts come through cases sometimes there is no seal or anything to prevent oil from escaping apart from them being above the oil level but when running some oil escapes and here you might need some ingenuity to fit an O-ring or lip seal, but on your T100 it should only be a case of making sure all seals and O-rings are in good condition (i.e. new) and present. Sometimes with old motors the engine breathing was a bit inadequate too so it's worth improving the breathing system especially if you intend to use the machine a bit spiritedly! And Don't overfill the oil tank either or it will throw it out of the tank breather!
All in all, to get the best out of an old bike you have to be a bit of an engineer - you can't expect to just get on them and ride like on a modern bike. You WILL have to get the spanners out most times that you get the bike out! It can be very satisfying when you get it right though!
Certainly with modern gasket sealants and technology it should be possible to get most engines pretty oiltight - it's not always easy though and sometimes takes a bit of thought and ingenuity to get there! Basically it's all about good assembly - the first thing is to make sure that mating faces are flat and undamaged. Use a sheet of fine wet and dry paper on a surface plate or sheet of glass to flat them down. You will find that most old engines are put together with greased thin paper gaskets between faces which can be dispensed with and a good liquid gasket sealant such as ThreeBond 1104/1194/1184 used in its place. Always use sparingly on dry faces though and be especially careful if oil passages run through the joint. Watch it though when the original gasket is a thick one because there will probably be a reason for this such as clearance being required for something to work. In this case either assembling with the faces cleaned off with a bit of thinners on a rag and an new, bone dry gasket or a bit of sealant smeared on either side of it will do the job. Where shafts come through cases sometimes there is no seal or anything to prevent oil from escaping apart from them being above the oil level but when running some oil escapes and here you might need some ingenuity to fit an O-ring or lip seal, but on your T100 it should only be a case of making sure all seals and O-rings are in good condition (i.e. new) and present. Sometimes with old motors the engine breathing was a bit inadequate too so it's worth improving the breathing system especially if you intend to use the machine a bit spiritedly! And Don't overfill the oil tank either or it will throw it out of the tank breather!
All in all, to get the best out of an old bike you have to be a bit of an engineer - you can't expect to just get on them and ride like on a modern bike. You WILL have to get the spanners out most times that you get the bike out! It can be very satisfying when you get it right though!