KX60 top end question, Ring position?

[STEVES937]

I'm replacing the piston, pin, bearing and rings on my boy's rocket.

Is it standard practice to hone a plated cylinder?

Where should the ring ends be placed? (could the ends cause damage if at a port?)

Last, what is used to lubricate the rod pin needle bearing?

Thanks, Steve

[berudd]

Unless there is some damage to the cylinder you do not need to hone it. Does the piston not have a locator pin in the ring grove for the ring gap? If the piston is not designed that way then it is not critical. With pistons like this the ring will actually rotate some as the engine runs. Assuming the cylinder is round that is. This is how some engines are designed and I think it is more common on the smaller engines. Use your premix oil for assemply lube.

If you need help with a mini go to ktmtalk.com. It is a much better forum.

[FFRacing79]

All 2 strokes have a locator pin in the ring land to keep the ring from rotating. When installing new rings it is always best to deglaze the cylinder. A standard ball hone or even scotchbrite will work. Just make sure to clean the bore afterwards with a high detergent lube such as ATF or marvel Mystery oil...just keep wiping till the cloth comes out clean or with out any grey color. Tdub/FFRacing

[Polar_Bus]

I'm replacing the piston, pin, bearing and rings on my boy's rocket.

Is it standard practice to hone a plated cylinder?

Where should the ring ends be placed? (could the ends cause damage if at a port?)

Last, what is used to lubricate the rod pin needle bearing?

Thanks, Steve

NO, NO , NO!!!!!!!

Do not hone a nikisil cylinder. The plating is a very special "roughed" surface engineered to hold oil. If you hone the surface, you destroy all the advantages of nikisil. If you have some scuffs on the cyl, just gently sand the scuffs with some 320 grit emery with some oil.

[The Spanky]

Two-stroke rings have to be kept from spinning with a locator pin in the ring groove, or the end of the ring will snag the edge of a port and trash the engine. You won't even be able to install the cylinder if the ring end isn't at the locator pin, or you'll break the rings trying to install the cylinder.

You don't hone plated cylinders, especially not with ball hones. If the cross-hatch marks are no longer visible after thoroughly cleaning the bore surface, then the bore is worn out, and it's time for a re-plate.

If you hone a serviceable plated cylinder with a ball hone, you will actually smooth down the peaks of the cross-hatch, which will do two undesirable things to the cylinder.

First, it will increase the piston-to-cylinder clearance, making the rebuild a complete waste of time and money.

Second, by smoothing the cross-hatch, you increase the surface area of the bore surface, and decrease the volume of the cross-hatch valleys. The increased surface area will slightly improve heat transfer, but will also increase friction. And the reduced volume of the valleys will reduce the amount of oil retained on the bore surface. Combine increased surface area with reduced lubrication, and you get increased wear rate and higher heat production. Bad juju all around.

Just clean the bore surface thoroughly with a Scotch Brite pad and soapy water. Rinse the cylinder, and wipe it down with a white paper towel. If the paper towel doesn't stay white, clean the bore again until it does.

Bottom line is, after cleaning the bore surface with a Scotch-Brite pad and soapy water, if you don't sill have a well-defined cross-hatch, the cylinder is worn out.

You can lubricate the wrist pin bearing with pre-mix oil. I use Marvel Mystery Oil, but the pre mix oil works fine. Before you install the cylinder, make sure there is about 1/8 to 1/4 inch of two-stroke oil in the bottom of the crankcase. If there isn't, pour a tablespoon or two in there. Assemble the top-end dry, except for the wrist pin bearing.

[FFRacing79]

NO, NO , NO!!!!!!!

Do not hone a nikisil cylinder. The plating is a very special "roughed" surface engineered to hold oil. If you hone the surface, you destroy all the advantages of nikisil. If you have some scuffs on the cyl, just gently sand the scuffs with some 320 grit emery with some oil.

I am really getting tired of discussing the properties of Nicosil with people who have no first hand knowlege. A standard ball hone found in most shops will NOT even begin to touch the surface of good Nicosil. The plating is so hard you will damage the hone long before it will even take a measurable amout off the bore size. But nothing I say will change your misconceptions, so I wont bother. But hey, I am sure you have plated and honed 100s of cylinders. ?

[The Spanky]

A standard ball hone found in most shops will NOT even begin to touch the surface of good Nicosil.

Unfortunately, Kawasaki doesn't have "good" nicasil. Their plating is pathetically soft in comparison to almost any other manufacturer, and a hone will damage their OEM plating, assuming the original piston and rings haven't already worn through it when it's time for a rebuild. I've rarely had a KX cylinder last longer than the first rebuild. After I get them replated at US Chrome, all is good though... ?

[Polar_Bus]

I am really getting tired of discussing the properties of Nicosil with people who have no first hand knowlege. A standard ball hone found in most shops will NOT even begin to touch the surface of good Nicosil. The plating is so hard you will damage the hone long before it will even take a measurable amout off the bore size. But nothing I say will change your misconceptions, so I wont bother. But hey, I am sure you have plated and honed 100s of cylinders. ?

Dude, a cylinder hone CAN ABSOLUTELY wear into a nickasil cylinder if enough force is applied (I work for a dealer, and i've seen it done). Kawasakis are WELL known for micro thin nikasil coatings (but you already knew this right???). So do us all a favor and keep you in depth, aggorant comments to yourself. We welcome education. This is the internet, and there are some people who are no "brilliant". Thank you,

[FFRacing79]

Dude, a cylinder hone CAN ABSOLUTELY wear into a nickasil cylinder if enough force is applied (I work for a dealer, and i've seen it done). Kawasakis are WELL known for micro thin nikasil coatings (but you already knew this right???). So do us all a favor and keep you in depth, aggorant comments to yourself. We welcome education. This is the internet, and there are some people who are no "brilliant". Thank you,

Sorry Polar but you are wrong. Kawasaki just went to "nicosil" recently, finally abandoning electrofusion. The thickness is not as relevant as the hardness of the coating(apparently Kawasaki's isn't as hard as most). But even still, deglazing with a ball hone will not alter the clearance. In depth and arrogant? I have covered this topic many times in the past. I helped start up one of the best plating companies here in the states. I have seen up close and personal the plating process at the UK's premier plating company, who do most of the Formula One work...so close in fact that confidentiality agreements had to be signed. I have participated in countless tests of different platings from different companies and OEM cylinders.

Just how much "force" can you apply with a ball hone?? Not that it matters.

Maybe my post wasn't as "in depth" as it should of been, but like I said it has been explained over and over and over again. There are MANY misconceptions on the properties of nicosil out there...just trying to clear some of them up. But