Montana engine tuner / Head squish questions

As the title says I'm looking for someone who can do engine work in Montana. More specifically I would like to get my head machined for proper squish. The bike is a 2013 KTM 250sx. Currently I'm living in the northeast corner but travel through the state often enough. I have no problem with sending my head off to wherever but dont want the down time involved with that. I was hoping to get this work done before snow falls but if that's just not an option I'll just send it off this winter.

So the question stands. Does anyone know of a tuner in Montana capable of this? I have a machine shop near by that builds and tunes engines for cars/hotrods. Would this shop be able to do this work as well as the next tuner? Do different tuners machine different squish or do they all achieve relatively the same thing?

All thanks in advance :)

I'd suggest:


1) Figuring out the squish clearance you want (.7mm / .027" should work well, but it's likely you could find specific info for your bike online)

2) Measuring the present clearance (real easy - you'll need some .050" solder, possibly thicker)

3) Taking the head to a good local machine shop to have it milled, or send it out if necessary


This way you can use any machine shop you want, and just give them a specific task to do.



So if I can figure out the proper clearance all I have to do is have it machined down to achieve that. With that said wouldn't the bowl also need to be machined out to compensate for the extra compression? And wouldn't bowl shape alter the combustion?

I can't imagine tuners handing out information like this. Its a cheap mod to do. I just dont care for the down time. If I could take it to my local machines and have it done in a few hours I would be very pleased.

It really depends on the measurements you get (I take one from each quadrant, then average them).  If only a small amount needs to be removed, especially when the squish band doesn't start right at the gasket surface, the squish area probably won't need much if any work done to it and compression shouldn't increase much.  If you need to remove a lot of metal, that's a different story.



ktm has different base gaskets to set the squish, I'd do that before cutting the head and set it to what they recommend for the SX head, not an arbitrary number.   The sx chamber design is already a high squish velocity design, the effect of reducing it's clearance tighter than ktms spec could require some race fuel to keep it safe.

Edited by highmarker

Try Ron Black at RB Designs in Portland Oregon.  You can UPS the head back and forth and it'd likely be ~1 week total time.  He did mine and I'm very happy with it.

Aside from the basic head cutting, you can have chamber volume corrected to maintain compression ratio, so it can be run on pump gas. RB-Design has a good rep for good work, relatively quick turnaround. Read the measurement instructions on the website. Measurement & shipping instructions are pretty clear, so you can have your work done, and parts shipped back in a timely manner.

Edited by bowhunter007

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