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2005 CR250 Squish questions

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I have a basicly stock 2005 cr250. Rejetted with a keihin 38mm AS & JD needle and a flywheel weight. Overall the bike runs good and pretty smooth, but lacking at the bottom a bit. Thinking about getting some work done to either the head or head and cylinder to clean up the jetting and hopefully gain some down low for woods riding.

Havent yet checked the squish. From many searches, sounds like the common consensus is to reduce the squish to around 1.5mm and re-shape the bowl to stay on pump gas.

Is it better to reduce the squish thru removal from the bottom of the cylinder (lowers ports) or off of the head surface?

I know lots can be gained thru porting and case volume work, but I am trying to keep the cost down. Are the differences pretty noticeable when adjusting squish without porting?

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I had a Tom Morgan- built motor in my '02. He said the best way to get low-end power was to cut the base of the cylinder, changing the port timing. I never tried the Keihin carb (but wish I had...). The head was re-shaped and squish set at .040 (1 mm). It made way more bottom end, but I still had to run at least half race gas/ half pump, and the jetting was still finicky, and I still had an intermittent lean condition and pinging problem (traced later to a crank seal installed cock-eyed).

In that motor, the crank was balanced, cases matched, cylinder epoxied & ported, base of the cylinder cut, head re-shaped... blah blah blah...

In the end I spent a TON of money. I tried different pipes and reeds, and got noticeable results, but still wasn't satisfied with the bottom end.

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I havent run race gas and dont have too much trouble with pinging. Noticed the pinging more when I had the stock carb on, even with the JD kit in it.

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first thing to do is actually measure the squish, if its a tiny bit i take a shave off the head, when i dont know how much you need and either way i dont know enough about port timing enough to be brave and shave bottom of cylinder myself. As long as its not alot or just a tiny bit i would take off head side myself.

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