Rickick91
ArboristSite Lurker
Hello Everyone,
Long Time Lurker here soaking up all the wonderful knowledge and experience on this forum. I had dabbled with muffler mods on my new 562xp and MS241CM when I got them over the last few years but didn't want to screw them up as they were good and shiny. Lots of reading and the cult-esk following of the 346xp caused me to gravitate to it for a good 50cc class saw. I kinda jumped to the less plentiful sizes first with 60cc and 40cc, but its just the way it went. Now I'm back tracking to the 50cc to fill out my lineup and found a decent 351 on fleabay that surprise to me ran when received after replacing the pull starter.
I am building it into a 346xp with an OEM piston and cylinder, and some mild port work and thinner gasket to get about .020 squish. From what I gather from those who have done this hundreds of times that is a safe number. Here are some pics so far.
I know the 346 is a bit played out, but hadn't seen one ported exactly the way I did this one and wanted to get feedback on my choices for the transfer shape. I tried to flare them and case match without increasing CC volume to much. I flared the Intake side transfers both toward the intake and into the center divider to give it the maximum flow, and the exhaust sides which had more case space to work with I only flared to the exhaust side. I tried to remove any imperfections but only flared the first third of the ports to keep low volume and didn't really touch the outlets. I figured this layout would give all 4 ports the most equal cross section of the charge to give even flow.
I also widened the exhaust by 2mm to 27 mm width at the port, and squared it slightly. I was going to go to 29mm to be around 65% of the diameter, but chikened out as the port walls were getting below .120" in places. I matched the outlet to the gasket and polished with cratex on the dremel and the buffer wheel.
The intake was trued to the boot, and a bit of the bulge on the one side filed out a long with the casting flaws. sorry for the long post. I' ve done a lot on it the last few weeks.
Long Time Lurker here soaking up all the wonderful knowledge and experience on this forum. I had dabbled with muffler mods on my new 562xp and MS241CM when I got them over the last few years but didn't want to screw them up as they were good and shiny. Lots of reading and the cult-esk following of the 346xp caused me to gravitate to it for a good 50cc class saw. I kinda jumped to the less plentiful sizes first with 60cc and 40cc, but its just the way it went. Now I'm back tracking to the 50cc to fill out my lineup and found a decent 351 on fleabay that surprise to me ran when received after replacing the pull starter.
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