Help locating Honda Dream Rings

[G-Man]

George

That NOS piston is a genuine Honda part and most of the surfaces are as-cast. If there are sharp edges at the edge of valve pockets, I would smooth them off to prevent any uncontrolled combustion. You can polish the top of the pistons (remember to clean them well afterwards) but it probably won't do anything for engine performance.

With a shiny top the piston will go through several phases. When it is very shiny for the first few minutes of operation, heat transfer into the piston is reduced giving the piston an easier life. Once there is a thin flash of black carbon, the transfer will increase putting more heat into the piston. Of course as the layer builds up it insulates the piston again giving it an easier life.

In general then - it is probably better to leave it rough... Just for interest - take a look at the aerodynamics of golf balls which shows why golf balls have dimples - makes them go further....

http://en.wikipedia.org/wiki/Golf_ball#Aerodynamics

G

[GeorgeP1111]

In general then - it is probably better to leave it rough...

I appreciate the explanation.

I think the hardest part for me and probably others that are newbies when it comes to motor rebuilding (refreshing) is not knowing by sight whats good/bad (which comes with experience I know). I search all the postings here for answers, and I have the Bill Silvers CD, but what to do when you can't find the answer or the specifications in the book are wrong. It's hard to sort thru all the misinformation. But.... in the end it's still fun and so is the ride (and the pride), well worth all the effort.

Thanks for the help

George

[G-Man]

George

I've been an Engineer for 30 years and I still learn something every day (usually that I got something wrong the day before). The most common answer that you will get from an experienced engineer is "it depends". This means that everything in the world of engineering is a compromise. Basically that means the answer to "should I replace this" depends not on what it looks like but what you are going to do with it and how you are going to use it.

Honda built lots of compromises into these bikes when new and the same compromises face us when we fix or restore them. When I was a kid we only replaced parts if the bike wouldn't go without them being replaced. Even then they often got changed for slightly less worn parts from another bike. I remember once fitting some lower handlebars to a bike just so that I could re-use a throttle cable that I had repaired by cutting off the bad bit and re-soldering the nipple.

Nowadays we replace parts because they rattle a bit or are slightly corroded. Generally we all have much more money than sense now so that we replace bearings, rebore cylinders and replace lightly tarnished chrome, just to make our ride that bit more perfect. There's a great Vintage restoration book written by Radco.

http://www.amazon.co.uk/Vintage-Motorcy ... 0854294724

His philosophy is - if the bike was running OK when you took it to pieces - it will probably run OK when you put it back together with a minimum of replacement parts.

The simple fact is that scruffy, rattly motorcycles are at least as much fun as shiny museum pieces to play with and often more suitable for the purpose they were intended for.

Have fun

G