TMGT
Elite Member
I've had my Makita 6401 for a while and have been wanting to upgrade to the 79cc P&C for a while.
I started looking for a second saw years ago but nothing was showing up localy for a decent price.
Well, a few months ago clean 6421 came up for sale locally for a great price so I grabbed it.
After staring at it in the storage shed for way too long, I finally got it on the bench.
It was filthy, and I probably spent more time cleaning than doing the upgrades, cleaned up and new piston installed.
The squish was .028, more than ideal. I was shooting for .018-.020.
The base gasket was .014 so eliminating it all together would have yielded too tight a squish.
I was going to make a gasket from some .010 shim stock, but really didn't feel like making a gasket when I had a nice new one to install.
I ended up putting it on the lathe and turning the mounting flange down. It took a bit to get it aligned/trued.
Ended up with right at .020 which I'm happy with.
I started looking for a second saw years ago but nothing was showing up localy for a decent price.
Well, a few months ago clean 6421 came up for sale locally for a great price so I grabbed it.
After staring at it in the storage shed for way too long, I finally got it on the bench.
It was filthy, and I probably spent more time cleaning than doing the upgrades, cleaned up and new piston installed.
The squish was .028, more than ideal. I was shooting for .018-.020.
The base gasket was .014 so eliminating it all together would have yielded too tight a squish.
I was going to make a gasket from some .010 shim stock, but really didn't feel like making a gasket when I had a nice new one to install.
I ended up putting it on the lathe and turning the mounting flange down. It took a bit to get it aligned/trued.
Ended up with right at .020 which I'm happy with.