Honing?

[swehollow]

Hi guys. I just bought a 250 GG 2003. Im changing the piston, rings and connecting rod and have some questions about the cylinder.

1. Do you actually need to hone it?
2. What's nicasil?
3. Could it be damaged if honed?
4. Using scotch brite, is it really legit? How hard do you go at it?

cylinder is within tolerance etc.

Cheers from the swede!

 

[john r b]

Welcome, Just use scotch brite to deglase the cyl.

 

[shang]

Nickasil is a hard plating. It's really hard. All you really need to do is break the glaze on the cylinder. Go at it with the scotch brite. You won't hurt it. I've used sandpaper before to clean off pieces of melted piston and it's fine. Just make sure you clean it out really good when you are finished so that there is no abrasive floating around in there.

 

[blamir]

Which side of scotch brite we have to use ??

 

[gasgasman]

I use a 3" ball hone with lots of machining oil..
Total run time is about 10 sec. with an up and down action to give a good cross hatch pattern.

 

[swehollow]

These are all good comments.

Would i gain anything by leaving it to a real machine shop? Or is it just a waste of money?

And about the scotch, since english is not my native language, i suppose you guys are refereing to the brown scotch ? http://www.freemansupply.com/productimages/Xplus91.jpg

 

[Zman]

Taking it to a machine shop with a diamond hone, will true the bore and will remove minor high spots like ridges at the top of the cylinder and the sides of the cylinder that wear less. A round cylinder will provide a better ring seal. I use Ryan Callies at Finishline Engine. http://www.finishlineengines.com/. If your cylinder is really worn he will let you know and if you chose to he can get it replated for you.

I thought I read or heard that ball honing a two stroke could result in chipping the plating on the ports.

 

[motopsycho87]

Scotch brite pad or 500+ grit Emory. Diamond or carbide will damage it. The coating is very thin and the aim is to remove the glaze, not create a surface to bed in. The rings and cylinder are not designed to bed in. They are both coated for low friction and wear.

 

[Brian VT]

...I've used sandpaper before to clean off pieces of melted piston ...

A safer (for the cylinder) method is muriatic acid on a Q-tip. Dab it on the aluminum, let it sit for a minute or so, rub it off. Repeat as necessary. I've saved lots of chainsaw engine cylinders this way. Just be careful not to breathe the acid fumes.

 

[shang]

A safer (for the cylinder) method is muriatic acid on a Q-tip. Dab it on the aluminum, let it sit for a minute or so, rub it off. Repeat as necessary. I've saved lots of chainsaw engine cylinders this way. Just be careful not to breathe the acid fumes.

That's good advice. Sounds a lot easier than sanding too. I hate sanding! Thanks!

 

[swazi_matt]

There is a YouTube vid by slavens racing (I think) referenced on the forum that says nothing more than a solvent and a soft cloth

 

[bowhunter007]

There is a YouTube vid by slavens racing (I think) referenced on the forum that says nothing more than a solvent and a soft cloth

http://youtu.be/vaFp8aYkHNA?list=UUerGVI2Oain-k_QfSBn1zbw

 

[Zman]

Yes the plating is thin but diamond hones are the way they finish a cylinder after it is plated. I have had several well used plated cylinders diamond honed to true them and refinish them so I could use them again without needing to replate them.

 

[(F5)]

1st off get a real good light in there & inspect the plating. If there is flaking or real grey areas of aluminium coming through it will need a re-plate.

The stuff is really tough and most of the time a clean up with scotchbrite (plastic kitchen pot cleaner) to remove any glaze and you're good to go. Sometimes you don't even need that. Don't be too critical of discolouration.