Originally Posted by
xr-stu
tolerances and whats acceptable, do they vary from engine to engine, or is there a generally accepted standard for bearings and ring gaps etc
They vary a bit from engine to engine, but there are general rules of thumb you can work too if you cant find the specific data for that engine etc.
Like a four thou per inch of bore on ring gaps is not a bad ballpark, 2 thou for main bearings etc
honing the bores, is it required and the best procedure
Yes its required or the rings wont bed in, if I were you I would use a flexhone rather than a 3 prongy thing, I have one somewhere right size for that engine I think but will need to check.
assembly lube (a thick oil or a grease?)
Its not a bad idea, but on just a quick freshen up like that engine oil will be fine to assemble with IMHO
initial start up and running in
Keep revs low initially, vary load though, lots of on and off the throttle.
what solvents and cleaning processes are best, or to be avoided
Brake cleaner is cheap and cheerful
and any other general advice. as i said im happy with the basics, ive done heads before, lapping valves etc, but not done a proper rebuild and want to make sure its done 100% properly!
not sure if its the replacement engine you are rebuilding or the original one?
Id not bother with crank grinds and stuff on such a cheap engine to replace, so I would only start with what seems like a decent working one in the first place, although then you have to ask if its worth bothering to rebuild anyway as you arent really improving anything anyway by a significant margin!