smarsh
Been Around the Block
Hey
I'm currently working through my first engine rebuild, a 1975 CB550K, and am trying to ascertain what piston and ring sizes will be correct to use for rebuild.
The motor has done 16000 miles. The cylinders look pretty good, the usual build ups at the top and bottoms. Heres a pic. Any texture you can see is just a light coating of oil & WD40.
The cylinders are all smooth to the touch, and in the centre of the stroke, I can see the original cross hatching.
I have measured the cylinders top and bottom, in X and Y axis with digital verniers. They all come in between 58.50mm - 58.52mm.
I also made a device to measure deeper in the cylinders, and am confident that the cylinders are not tapered or out of round.
I gapped the original piston rings in the cylinders, and their ends gaps were all within spec, but I plan to replace with new rings.
The pistons diameters are within the specs of above 58.35mm, and I plan to use the original pistons.
The Clymer manual says that a rebore of the cylinders is needed if cylinders measure 58.60 mm or over.
My plan was then to hone the cylinders with a 320 Grit Silicon Carbide Flex Hone to remove the carbon build up and make a good cross hatch. Then re-measure the cylinders once they look clean. As this is my first build, I'm not sure how much metal I will need to take out during honing.
SO, my question is, am I right in assuming that standard pistons and rings are ok to use in cylinders up to 58.59mm? If not, what is the acceptable clearances on ring sizes?
Obviously I would imagine the closer to 58.50mm the better, as I'd assume more clearance would lead to quicker wear in the rings/cylinders?
Ideally I would rebore the cylinders, but given my location, that isn't really practical. That said, I want to do it right, so if thats the best approach, then I will do that.
Just hoping someone out there with more experience would be able to confirm whether or not these clearances and my assumptions are correct.
Thanks!
I'm currently working through my first engine rebuild, a 1975 CB550K, and am trying to ascertain what piston and ring sizes will be correct to use for rebuild.
The motor has done 16000 miles. The cylinders look pretty good, the usual build ups at the top and bottoms. Heres a pic. Any texture you can see is just a light coating of oil & WD40.
The cylinders are all smooth to the touch, and in the centre of the stroke, I can see the original cross hatching.
I have measured the cylinders top and bottom, in X and Y axis with digital verniers. They all come in between 58.50mm - 58.52mm.
I also made a device to measure deeper in the cylinders, and am confident that the cylinders are not tapered or out of round.
I gapped the original piston rings in the cylinders, and their ends gaps were all within spec, but I plan to replace with new rings.
The pistons diameters are within the specs of above 58.35mm, and I plan to use the original pistons.
The Clymer manual says that a rebore of the cylinders is needed if cylinders measure 58.60 mm or over.
My plan was then to hone the cylinders with a 320 Grit Silicon Carbide Flex Hone to remove the carbon build up and make a good cross hatch. Then re-measure the cylinders once they look clean. As this is my first build, I'm not sure how much metal I will need to take out during honing.
SO, my question is, am I right in assuming that standard pistons and rings are ok to use in cylinders up to 58.59mm? If not, what is the acceptable clearances on ring sizes?
Obviously I would imagine the closer to 58.50mm the better, as I'd assume more clearance would lead to quicker wear in the rings/cylinders?
Ideally I would rebore the cylinders, but given my location, that isn't really practical. That said, I want to do it right, so if thats the best approach, then I will do that.
Just hoping someone out there with more experience would be able to confirm whether or not these clearances and my assumptions are correct.
Thanks!