ms361 Port work

I just did a thread earlier on me being a newbie. So I thought you guys might like to see how I do some of my saws. The 361 is a beast of a saw and a common saw for a lot of people so I thought I would do a short build thread on one. Nothing fancy but give you my recipe. And i have a few pics so I maybe able to pull it off. Lol. I'm not good with vids cause I do all my posting with a smart phone and have yet to figure out how to down load vids.

 

Hers the victim.

 

I'm flying off the seat of my pants. I usually keep really good notes but can seem to find my compete formula. But it's not important. Final numbers are what counts. These start off with an exhaust height of 106° and the trans at 137°. The trans are staggered in these the highest point is always the intake side. I believe the the intake starts out about 75°. Can't remember that for sure off the top of my head. But that's close.

 

I cut .035 " off the squish band and then cut the base so my squish ends up at .025" I don't like really tight squishs. This yields a compression of just a little over 200 lbs. Makes for a nice torquey saw when combined with the port work.

 

You will needs to take the video and then download it to a site like youtube and then link it here by sharing the video and putting the link here. As far as I know the site here doesnt host videos.

This was complicated for me at first, I couldnt figure out how to put stuff on youtube bit finally figured it out through the app. There is a tutorial here by pete I think on how to post to youtube.

But carry on. Your already way over my head with your post but I will follow along.

 

With the squish band cut my intake winds up around the 78-79° mark. I then us the piston to push the ring up in the cylinder so I can mark the bottom and roof off the intake. I use a red permanent marker to draw the lines. I then use use a a 10mm flat metal ruler to mark the sides. A business card will also work. So u end up with a square mark around the intake. I do not widen the intake on this model. Just square it up and and blend all the way out. These pics show a stock and a ported cylinder. The dirty one is stock.

 

Cool as chit.

 

I set all my heights by pushing a ring up and marking it with a permant marker. On the trans I push the ring up and set them at 118-120° the only time I've seen this 2° make a big difference is if your porting a big bore kit. And that's to do with case volume, velocity, etc. On these I also widen the rear trans just a little back towards the intake.

 

Now the exhaust. I widen it out to about 65% on this saw. Heeding in mind the skirts and ring location ends. I flatten the roof a little and blend out. On the outlet it's made much bigger. Just lay the gasket on the cylinder and mark it out. To match I generally go just a bit more but gasket matching works really nice. The dark spots on the oem cylinder pic will all be ground out.

 

On the trans tunnels I just smooth them up a bit and get the casting marks out. Then I use a round grinding stone to put the bevels back on all ports. And the cylinder is done. I know this is just a quick thread with not full details but I hope it helpful.

 

Very nice work

 

I advance the timing a quarter of a key and then I Muffler Mod it. I decriminalization the muffler and remove all the baffles. I port match the muffler inlet to the cylinder out let. I then add a second port on the opposite side of the main exhaust port and open up the main. Now I didn't like the outcome of this one but it gives u an idea. It's at 95% of cylinder exhaust outlet.

 

Will it run like that?

 

I know this was short and sweet but hope it's helpful. So in recap final numbers are intake 102°, trans 120°, intake 79° and timing advanced 1/4 of the key.

 

Sweet info.

 

It runs very nicely like that. IMO. Lol

Just hope it's helpful.

 

Very helpful thank u.

 

Niice !

 

????