Cylinder Honing?

[DirtBiker125CR1313]

Ok so I am doing my first top end rebuild and I need to know if I need to hone out the cylinder or not. I am ready to order the stuff but I do not want to if I do not need to. Also is there any thing else I need to replace when I do the top end rebuild besides base gasket, head gasket, piston, rings, cir clips and wrist pin?

 

[David_L6]

If your cylinder is plated don't worry about honing it.


I always replace the wristpin bearing when I do a top end.

 

[DirtBiker125CR1313]

If your cylinder is plated don't worry about honing it.


Well how do I tell if it is plated? It is a 2007 Honda CR125R.

 

[David_L6]

If it's a stock 2007 Honda cylinder, it's plated.

Most likely it's plated unless someone had it sleeved before you bought the bike (assuming you didn't buy the bike new).

When you get right down to it, honing isn't always necessary anyway. My hydroplane motors are built with sleeves. I don't always hone them when I re-ring a motor. I'd be willing to bet that almost as many motors have been worn out with a hone as have been worn out by running them.

 

[whenfoxforks-ruled]

How does the shop manual state to remove the aluminum flashing off the cylinder before a new top end? It looks fine, like some people have magna vision or something? And the last I checked it was oven cleaner for flashing. Not as macho, but what ever? Sleeves, do a search? I do not like them or advocate using them for any reason. A cr125, like it needs a shorter ring life? Take care of the plated bore, if it needs help send it to Forward Motion. Vintage Bob

 

[julien_d]

Agreed. I use muriatic acid on a towel to clean the aluminum deposits off a plated cylinder. You must be careful though, if it gets on any bare aluminum it will etch it in short order.

 

[whenfoxforks-ruled]

Is the etching what makes the aluminum appear to be pickled?

 

[DirtBiker125CR1313]

How should I clean the cylinder? Should I just rub the muriatic acid in? Also how long should I do that?

 

[julien_d]

Wipe it on, wait a few seconds, rinse it thoroughly. Again, muriatic acid can be dangerous. You can also just use some lubrication and a green scotch brite pad with lots of elbow grease.

Yeah, if you get any of the acid on aluminum parts of the cylinder it will come out looking pickled, and even pitted if it stays on too long.

 

[whenfoxforks-ruled]

A little more elbow grease, and wd40 with the green scotch brite pad, it will remove it. The acid kinda burns it off, so do not inhale the fumes. I like the long cotton swabs, and use non lemon oven cleaner. The worst area is towards the bottom of the stroke and any port bridge areas. The hone in the right hands can do the job also, just mind the amount of material that is being removed, 2 or 3 strokes is it! Neither one will tell you if the cylinder is serviceable, it can still be out of round. When you get done cleaning, time to measure.

 

[DirtBiker125CR1313]

Ok I will Just use wd40 and the green scotch bright pad just to be safe. One more question. How long will I have to rub the cylinder?

 

[RM_guy]

...until a Genie comes out :laugh:

Sorry, couldn't resist. You'll want to rub it long enough to remove any oil glaze buildup and/or alum deposits. Try to maintain a 45 degree angle and get a nice crosshatch pattern while you're cleaning it up.

 

[_JOE_]

Wiseco also makes a bore brush for this.......

 

[DirtBiker125CR1313]

Ok thanks for the help everyone!

 

[avidrider]

Honing is usually reserved for older iron bore cylinders when re-ringing a piston and not usually necessary for something with a nicasil or similar plating. The plating is really hard and can usually just be cleaned up by the aforementioned techniques. The thing to loook for is the plating coming off or other damge in the cylinder wall, normally the result of seizure.