Suggest a shop for machine work?

["Dangerous" Dan K]

I'm exploring all my options for the top end of my KX125. If I decide to send it out, the only place suggested to me so far is cmmachine.com. They are @ $85 to machine the head. At that point I'm thinking I'd spend the extra $10-20 to just get a new one.

If the bore needs attention it'd be $240 to rebore and replate. That seems reasonable.

Wondering if any of you guys have had similar work done, and if there's a place you'd suggest.

Worst case through cm machine I'm looking @ 465 for the head machined, the cylinder rebored and replated, piston, ring, and gaskets. Not too bad. It'd be nice to have a suggestion on a place some of you guys have sent stuff to though.

The other thing is, they rebuild, hone, replate everything for $465. For $550+shipping I could just get all new stuff.

[BMFR6]

if Paul doesn't respond, I'd PM him. he will most likely have some places for you.

[stoinkythepig]

Only $85 more + shipping for all new? Seems like a no-brainer. Only thing I'd do is bring the online prices to a local dealer and ask them to match. They did for me when I needed 2 grand worth of new plastic.

["Dangerous" Dan K]

I'm thinking along the same lines... when I'm throwing out $500 anyway another $100 to go all new seems smart. Of course, if I can find another reccomended shop that will do the same work for less and still do a good job, it might become a more difficult decision. If Pail doesn't chime in soon I'll shoot him a PM.

[6 Fingered Man]

If you get the cylinder bored you should have the head machined to match the new bore. I would have your curent head done rather than spend $100 on a head and have to have it machined any way. Unless you go with stock bore but why do that

Just my opinion.

["Dangerous" Dan K]

If you get the cylinder bored you should have the head machined to match the new bore. I would have your curent head done rather than spend $100 on a head and have to have it machined any way. Unless you go with stock bore but why do that

Just my opinion.

If I go with boring it, I would. If I go all new I may keep the stock bore. Still undecided.

[6 Fingered Man]

whats the cost difference form new standard bore to new big bore? Seems like it should be close, same parts just larger.

["Dangerous" Dan K]

New big bore is 600-700 depending on which I go with.

[6 Fingered Man]

http://boston.craigslist.org/gbs/pts/1058369501.html

Have a welder?

[KB]

Why do you need the head machined? Is it warped or just pitted from the pieces of the piston?

I would instead of boring and replating consider a sleeve. It's usually half the price of plating. And if you smoke another piston you can have it bored for around 100 bucks.

Plating is used because there is no sleeve just an aluminum hole that is roughly the bore size and instead of a cast iron sleeve they plate the aluminum with Nikasil.

KB

["Dangerous" Dan K]

I actually don't need the head machined, it turns out. Should have updated this thread too, whoops. The head was just pitted from pieces of the piston or detonation or whatever, but my local shop said that a simple cleaning up (as in sand/file/whatever, not solvent) and use it. The cylinder passed their inspection with flying colors, and was deemed to be in "surprisingly good shape". got a top end kit on the way, and should be good for reassembly soon.

[richw]

First sand the polish the cumbustion area make it shine. Leave a spark plug in to protect threads.

Get a pc of double thick glass

Get wet sandpaper 220 Grit up on the glass this is a flat surface

Wet sand head surface in a figure 8 motion rotating the head 90
degrees every few motions. Use just finger tip pressure near the center Try not to push it so edges dig in

Look at it and when all the surface is being cut by the sandpaper you are done. First you will usually see "high spots" near the bolt holes.

Wash 3 times in hot water make sure all grit and sandings are removed.

["Dangerous" Dan K]

First sand the polish the cumbustion area make it shine. Leave a spark plug in to protect threads.

Get a pc of double thick glass

Get wet sandpaper 220 Grit up on the glass this is a flat surface

Wet sand head surface in a figure 8 motion rotating the head 90
degrees every few motions. Use just finger tip pressure near the center Try not to push it so edges dig in

Look at it and when all the surface is being cut by the sandpaper you are done. First you will usually see "high spots" near the bolt holes.

Wash 3 times in hot water make sure all grit and sandings are removed.

Thanks for the reply. Timely, considering I plan on doing it this weekend. Sweet.

I’m a bit confused though, what is the glass for? Am I wrapping it in sandpaper so that it’s my “sanding block” so to speak? Unless I’m picturing this wrong, wouldn’t that only put paper pressure on the 4 corners of the glass, since the head is domed?

I’m all about heeding some advice on the best way to sand down that head, just want to fully understand how I’m being told to do it.

[Paul_E_D]

The glass is just to sand the mating surface flat. Sanding the dome itself by hand just requires patience. It's a little sketchy to do this because you will be changing the volume and shape in an uncontrolled way, but if you just go easy and take down the bumps you'll be fine. Don't try to sand the pits entirely away. Then you will have really altered things.

["Dangerous" Dan K]

The glass is just to sand the mating surface flat. Sanding the dome itself by hand just requires patience. It's a little sketchy to do this because you will be changing the volume and shape in an uncontrolled way, but if you just go easy and take down the bumps you'll be fine. Don't try to sand the pits entirely away. Then you will have really altered things.

Ah... now I gotcha, thanks. There's only one bump, the rest is all pitting. From what my local shop told me the pits are no big deal, just sand the one protruding burr off and I should be good to go.

Do I want to sand the mating surface even if it's smooth? I figured after a good solvent cleaning it'd be set to go.

[Paul_E_D]

Yeah, you overheated the bike. Just do it.

["Dangerous" Dan K]

Thanks. Will do.

["Dangerous" Dan K]

Got her fired up today... runs better than it has in as long as I've owned it. Thanks for the help.