New cylinder bad compression

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Sanded the bottom of the cylinder. Squish is now 0.020” (0.5mm).
Rebuild the saw yesterday and let de gasket dry for about a day.
Tried the saw today, fired up quickly. Tried a small piece of oak, lots of power (for small saw at least)!
Then the saw died, could not get it running again.:chainsaw:
Checked all the basics, spark, fuel, carb etc. It would not even ignite for short period. Lots of compression.

Finally discovered the gap between flywheel and ignition coil was very small. And noticed the flywheel had scratched the ignition coil. Tried to gap it correctly, but was not possible. Could not move the ignition coil away from the flywheel. So by sanding the bottom of the cylinder the flywheel came closer towards the ignition coil. Solved this by filings the holes in the coil as much as I dared and removed the top part of the thread on the screws holding the coil.

And another try and the saw worked and kept working! Very happy!!:happybanana:
I will test is more extensive in a few weeks and see how it holds up.

Thanks for the advice!

I would compare the dimensions of the old piston and the new one and see what you come up with.

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Also compared the old cylinder dimensions and new cylinder dimensions.
The new cylinder bore is 0.4mm deeper compared to the original one. This didn’t explain the squish being 1.4mm. So also measured the piston, the total height of the original piston and new piston was identical. But I discovered the pin hole had an offset of 0.4mm. So the new piston + cylinder had 0.8mm more squish compared to the original cylinder.

And advice for other people, do not buy this type of cylinder! Maybe mine as one of a kind, but be warned. At least if you do not want a shitload of work. I added pictures of the cylinder when I got it. On ebay there are several types, there are with screws in the sides and without.
17-10-26 14-55-54 5991.jpg 17-10-26 14-55-57 5992.jpg 17-10-26 14-56-01 5993.jpg 17-10-26 14-56-05 5994.jpg
 

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