Topic: Question about honing cylinders

[Moosey]

I have some leaking gaskets on my 71 cb500. I will be taking the top end off, lapping the valves, and replacing the gaskets. The compression is good on the cylinders and I may not need to replace the rings. Do I still hone the cylinders even if not replacing rings?

[Trad]

It's your call. If it was running fine before and you have good compression you don't have too. If you're replacing the base gasket and pulling the cylinder jug off I would just re ring and hone anyway. Saves you the trouble of having to do it down the road.

[calj737]

If the compression is good and equal, leave the pistons and rings be! Maybe, just clean up the tops of the pistons if they're crudded up.

[flybox1]

Wouldn' t you let the the crosshatch, or lack thereof, be the determining factor? 

[70CB750]

No need for crosshatch if rings stay where they are.  Crosshatch is important for braking new or new for the cylinder rings in.

In another words, the engine does not need crosshatching on cylinder walls to run.

[strynboen]

presise...honing are mostly/ only for the rings to vear farster inn

...but shift for shure the valve steam sealing..they are often hard and cracket..and sucks oil ,specily by no trottelrun.. so vaccum builds up..and vhen give trotten again it often puts a small blue sky..vhen the oil are burned

[flybox1]

No need for crosshatch if rings stay where they are.  Crosshatch is important for braking new or new for the cylinder rings in.

In another words, the engine does not need crosshatching on cylinder walls to run.

Fully understood. 
My line of thinking, and please correct me if im wrong...with a engine of unknown mileage, and, if the factory crosshatch is no more, I would assume the rings/bore is worn enough to warrant a hone and re-ring?  I mean, it really is a $100, hour +/- job at this point.  For longevity sake. 

[70CB750]

I was wondering why would you ask that, with your experience.

My post is based on PO statement that the compression is good.

[PeWe]

The domino effect...
when cyclinder is off, pistons OK?  why not open crank case and find not that nice bearings, primary chains, very old chain tensioner if it is like a CB750 that definitely need to be replaced after many years. The rubber wheels become hard before 10 years. Cam chain and tensioner too when engine is opened. Clutch.... all o-rings, sealers, gaskets. Head overhaul cut valves, maybe new valves. ..... $1500-2000 US is my guess.
I know, I'm doing it again with my CB750.

[thirsty 1]

If it doesn't burn oil and has good comp. then I'd leave it alone. If you hone it you have to break in the new rings and unless your going oversize all your really doing is lower the compression by making the cylinders bigger around. Then you have to hope the rings seat in properly. if they don't then you have to take it back apart or live with a oil burner/smoker.  This just my opinion but I'd leave it alone.
Cheers bud and good luck I'm sure it'll be fine.

[strynboen]

domino..vhy push the bricks..if they can be standing.
.have not opend my bottom end of the 550,, if it all vorks perfekt..no plastic or metal in the oil..vhy use a lot of money..and probely not get any performance or ekstra engine safty or longer life..
mine have gone 75.000 km..this botten end #normaly# goes 100,000 km..so vhy go in at 75.000 and thange anything,,,vait to it real are vorn aut..
i often think that 75% of all thanged parts are not veared aut...or fabric vear data is near at all...

most vear are in the top end of engine..valve/valve steam seal/ seats/ gaskets/cam chain/tensioner rubberparts...are the real deal to thange..even it not are veared total aut

[alacrity]

I love Mr. Stringbean's direct translation of that idiom from his native language: "why push the bricks if they can be standing," indeed!

:-)

When you last did an accurate compression test, what did you learn?
When you last ran the bike and did a plug chop, what did they tell you?
Was it burning oil/making oil smoke only when running "hard" at higher rpms and oiling your sparkplug(s)  -- in this case the activity is pushing oil past the control rings into the combustion chamber.

These are the things I would want to actually know and use the information before doing anything to what might already be a very happy place...

Think of it this way - the cyl/piston/rings are working together like a very happy family. Would spend the money and time and $ to call in an invasive family counselor therapist to stir up all sorts potential problems (even if the hope is long term happiness) knowing there is a risk things could get worse in a hurry? Or would you think the risk of something that invasive is too great given that things are currently fine?

I know what I would do