Since there are different opinions on whether to hone or not, lets take a minute to review what the issues are and what can be gained by honing.
As the engine runs and the rings slide up and down on the cylinder wall, and the engine goes through countless heat/cool cycles, several things potentially happen:
1. the rings will scrape material off the cylinder wall - if this is measurable, there is a ridge at the top of where the top ring stops as it travels up the cylinder wall. At some wear point, the cylinder wall is considered "glazed" - this point is different to different rebuilders.
2. the piston skirt potentially scores the cylinder wall it the piston has enough clearance to the cylinder bore to c*ck (twist) enough to scrape the cylinder wall - if this happens there will be vertical marks in the lower portion of the cylinder wall, typically in a range of around 90* only.
3. the cylinder bore may go out of round due to the thermal cycling.
Now lets review what, if any, benefit honing will have on the situation:
1. If the cylinder is worn enough to have a noticeable ridge where the top ring stops travelling, then honing is typically not going to restore the cylinder - it should be bored out and oversized pistons installed. I've never seen (in photo or real life) a SHO engine that exhibited this amount of wear. While others may disagree, I have not considered a cylinder to be "glazed" unless the honing marks had disappeared. In the case of the typical SHO rebuild, the cylinder honing cross-hatching is still readily apparent.
It is important that the cylinder wall have visible cross-hatching to allow adequate oil retention on the cylinder walls. If the cylinder wall is too smooth ("glazed"), then the ring will wipe it too clean, not enough lubrication will exist and excessive wear will result.
2. If there is some slight scoring of the cylinder wall from the piston skirt, it is possible that honing will smooth this out and improve the situation. If there is significant scoring, then the cylinder needs to be bored oversize. This is especially true if the scoring runs up into the area where the rings ride, which in the SHO engine is a long way down toward the bottom of the cylinder wall.
3. While some people might claim that honing will make an out of round cylinder round again, it really will have virtually no effect on that. The only way to make it round is to bore it oversize, since the boring bar will make it round while the hone will not.
Round cylinder bores are very important to engines like these that have low-tension rings. Therefore, yamahaSHO's advice to take a seasoned block and bore it out will result in the best and most robust end result, if done properly. However, pitaSHO has said that he is after a good budget rebuild, not the 'uber-build', so boring a 3.0 to 3.2 is probably going to exceed the budget on this project.
If the original cross-hatching is still plainly visible, and no significant scoring is visible, no honing is required. Would it be better to do a light hone? Possibly, but I would only do a few passes with the bead tool, not using the 'regular' hone at all.
Would it be bad to do a 'full' hone? Probably, because in doing so one would likely open up the bores enough that the piston clearance would be too large, which would promote piston c*cking in the bore and causing more scuffing and more wear faster.
