1.6+ mm squish

[paulos]

After a minor top-end rebuild on an 05 ec200 I've re-measured my squish at about 1.6 mm.

I'm thinking this is worth addressing but what measurement is ideal? I always use Premium fuel at 98 octane and I'm more interested in fuel economy and jetting accuracy than sheer power.

My machinist is thinking 1.2mm max.

 

[thejackrabbit]

I have 1.7mm on my 2005 ec200 2.6mm on the inner edge of the squish band the fuel economy is definitely less than my ktm 200 which also has one size larger jets in it and a richer needle. I haven't measure the squish on the ktm, but I'm certain its in the 1.1-1.3 range with the entire squish band corrected.

 

[AZRickD]

Getting the head cut (even by the relatively pricey RB Designs at $75), it would be worth it just to find out. The time it takes to get it apart, rosin-core imprinted, shipped, and reinstalled is fairely painless as well.

I had RB cut the head (and open up the combustion chamber to maintain constant reasonable compression) on my 2005 EC250. It was about 1.05mm. I put the same cut head on my 2011 EC250R but kept the stock base stack so the squish measured 1.35mm. I figured it might give me a little less bottom and a little more top. And it did.

 

[motopsycho87]

From A Graham Bell's 2 stroke tuning.

My 300 is at 1.2, DIY jobby

 

[paulos]

Ok, so as low as 1mm on a 200? Thanks for the info.

 

[wa_ndro]

Give Dave a ring at Two Stroke Performance. He will sort you out - about $220.
Loads more bottom end, better economy, still plenty of top.

 

[Jakobi]

Wish we could get it done for $75 here in Australia! If you have a local machinist who is up to the task you might get it done cheaper, but you don't just want it skimmed. You'll likely want to recut the angle of the squish band to match the piston and then open up the compression chamber to hit the correct compression ratio.

I've had Dave at TSP do a couple for me and when you consider what he does for the $$ its not bad at all.

 

[AZRickD]

W3rd, Jacob.

RB Designs -- $75.

http://www.rb-designs.com/rb_designs_llc_005.htm

 

[Jakobi]

W3rd, Jacob.

Our time is more important than yours

Haha! Its all relative in the grand scheme of things.. or some I'm lead to believe. Everything costs a fortune here, as a result of us demanding so much more money for everything we do. It goes around and comes around.