Project The Second Fizzer

Part of the reboring process is to hone to the final size and surface finish.

 

Because the new rings have to wear in quickly to suit the bore that they are running in.

"A more likely explanation is that the roughness is needed only in the early stages of engine operation to enhance the removal or
wearing off of cylinder wall and ring material in places of high interference between these components. They are not made accurately enough to effect good conformity to each other and non-conformity causes excessive blow-by of gases and high oil consumption."
THE BREAK-IN STAGE OF CYLINDER-RING WEAR: A CORRELATION BETWEEN FIRED ENGINES AND A LABORATORY
SIMULATOR G. C. BARBER and K. C. LUDEMA

 

1/ Japanese don't specify anything much. They assume that we are all stupid and you should just buy a new bike. As an example, Honda do not make oversize pistons for many of their bikes.

2/ correct

Think of it this way. If you make the bore a bit fluffy you can quickly achieve a functional seal. If it is smooth and hard the rings will just destroy themselves.

Let's agree to use the right words here, and that is deglaze rather than hone. Those terms get used all the time but in the case of fitting some new rings it is just deglaze.

They are exactly the same moving parts, to the same tolerances.
Correct but those tolerances are very large when considering sliding parts in contact at very high speed. Bores are never round. Use a dial bore gauge and you see that they are all over the place and they are also tapered.

 

A piece of fine wet and dry paper with some wd=40 or kerosene and two fingers into the bore and sand diagonally enough to dull the surface is about all I do for a re-ring job if the bores measure true. Just be sure to wash well with HOT soapy water and wipe with an oiled rag to stop the flash rusting.

 

To de-glaze is exactly what it says... the bore surface glazes over time as the rings slide up and down... giving it a "shiny" appearance or a glazing...
It isn't just true on old diesel engines.. any diesel will glaze the bore if they are run under light load.... the rings tend to polish the surface which isn't good for oil control or proper lubrication.
Several things to do when re-ringing.. A you need to make sure there is no ridge at the top of the bore... B Make sure the bore is in spec... C lightly hone (and it should be a honing process using a fine stone and lots of oil). this provides a textured surface to assist bed in of the rings while retaining lubrication for the bed in process.
It is no different to what is done on cylinder bores (hydraulic cylinders) brake cylinder bores etc...
The last thing you need to do is the make sure the rings have sufficient side clearance and that the end gaps are within spec... and the ring ends are in the correct positions...
This stuff has been the same since the early 1900's... and we were taught the importance of honing cylinders (engines and hydraulics) during my Apprenticeship as a LAME (Licenced Aircraft Mechanical Engineer, or glorified Aircraft mechanic).
I am not up to speed on the latest developments with low tension (low friction) pistons and rings but the gear we are discussing in here is 20 to 30 year old designs and they do need to be honed...
There is certainly a difference in Power Honing and what you would do when re-ringing your engine...
Power honing is the final step taken on high performance engines after boring to get each bore to the exact (or as close as possible) with the correct crosshatch... all part of the "blueprinting" process.

 

I used a flexhone on my 400 cylinders and I was surprised how hard they are. You will need to use a bit of elbow grease when doing it manually. The good thing about doing it by hand is that it is cheap and easy to get the finish that you want. As Murdo said use hot soapy water because solvent tends to wash away the oil but leave the grit. I bought both genuine and Chinese rings. The Chinese items were within tolerance.

 

I usually just use a cheap hone and my 18v drill, it give's an excellent finish when you just want to re ring an engine



Here's a cylinder i've done, took 3 or 4 min's to get it cleaned up and deglazed

 

The hardest part about doing it is working out what speed to spin the drill at, and how fast to move it in and out of the bore to get the best pattern.

 

Nah only took a few second's to run it and move the drill in and out and look at the marking's it left
I reckon i ended up moving the drill in and out cycling it in 1 second
You need to make sure you don't go in too deep, or out too far so the the stone's don't cut away the top and bottom of the bore more.
I had about 1/5 of the stone come out each end of the bore on every stroke up or down
The stone's are pretty fine so they don't cut a lot of material on each pass

Too slow up and down the bore and the diagonal mark's left are sort of like this, very shallow


Too fast up and down the bore and they sort of go like this, very steep

 

Everything @my67xr said. The same with the brush hones which is why I made the video. It does not destroy the bore, they are not that abrasive. I made a video on my thread for that very reason http://2fiftycc.com/index.php?threads/hone-fit-new-rings.2939/