measuring squish?
 

when people refer to what their squish band reads are they measuring the thickness of the solder at its thinnest point or at it's thickest?

Thinnest point.
When I had RBD do mine seems He asked that I use a 2" piece hollow core solder directly across the top of the piston under the hole for the spark plug. The result showed the untouched part where the plug would have been (leave it out to do this) and the tightest area is around the plug hole. The head is then machined accordingly to match the squish desired while keeping the same shape as the piston dome.

Kudos to RBD. He did a great job at a good price and turn-around was quick. Very noticeable results on my bike. We haven't done my kids bike.

My bike has a .5 base gasket (dark green in color) I measured the squish and it came to be 1.7 and 2.5mm on the larger end, the piston looked good so I plan on just replacing the rings.
The bike is really soft on the bottom, could be jetting, but compared to the ktm 200 it's lacking, the mid range and top are strong

http://www.twostrokeperformance.com.au/#!important-info

The outside edge is your minimum clearance, which is what most refer to when they say their squish. Depending on how the rest of the head is cut in relation to the piston dome it may stay the same clearance across the band, or may open up some more as it does stock. The main thing to remember when adjusting the squish is to take into account that any changes also effect the trapped volume and thus the compression.

The 200 really likes increase of compression & decrease of squish. I closed mine up to 0.8, but I had to take some out of the bowl to reduce the compression that went too high. How high you can go depends ont he gas you will always run. Google how to measure trapped volume there should be heaps of info around. takes some time & careful tinkering but it is worth it.

Finally going to do my 300 tonight after a couple of years saying I will.

Nice one F5!

0.8 for the 200?? :eek: that's real close...

I run 0.5 on my 50 if that freaks you. Never hits despite 14,000 rpm.

I ran 14:1ish on the 200.


True to my word I took the head off the 300. I found the squish was a wedge shape. 2mm at the edge & 3mm at the inside of the squish. (my solder was only 2mm so I missed that until I used plasticine).

The piston has ~9* angle & the head ~ 13* Sheesh! talk about going for a low MSV.

I'm going to angle it 10* & close the squish down to ~1mm. This will raise compression waay too high so I'll pull out a few cc to bring it back to 12.5 - which is easy for me to kick, as I'm 5'8" & my swing loses effect when in a tricky trail section.

I threw it in the lathe & just scratched the anodising to see how flat I might make it but with the wobble in my poor old lathe I thought better of it & its going to a shop to do the flat surface. I'll then be happy to take area out of the bowl on my lathe & do the measuring.

My base gasket was actually a .30 green, I went ahead and ordered another .30 gasket, so the swish and compression will stay the same, but I did order new rings, because the piston had only a dime size of carbon build up on it. Thanks for all the info

As an educated guess you could probably take 0.5mm off the 200 head & at least get the squish almost working & a bit of a compression increase, as long as you never run less than 95 gas you should be fine. Think on mine I removed one of the 2 base gaskets & skimmed 0.9 but I did have to scoop a bit out as comm went up to 15.5:1