Husqvana 350/353 popup

[cranman1951]

He Gang...good afternoon. I started pulling apart a perfectly good running 350 yesterday to try some experiments . I dismantled and washed all parts and today started buttoning up the saw. This is the first time I've sanded the cylinder adapter flat using a technique I saw on Youtube ( Thank you Mattyo!) I just took a small plate of 1/4 inch steel and a sheet of 320 sandpaper and sanded the flats until smooth.....I was amazed at how out of flat they were. I used Yamabond 4 to seal the bottom, and got a .300 squish with the gasket delete and popup piston for a 353. I used the stock cylinder as it was in great shape...I really hate taking out a good piston...I hope to find a use for it down the road! This was my first time doing a squish test, and I hope I got it right. I ordered some stainless intake clamps for a 372 that just came in a few days ago. I'm really all thumbs when installing the 346 metal clamps that lock in with a snap, and the 372 clamp is a nicely made screw clamp that looks a lot easier to install. I just took a pair of side cutters to modify the intake manifold and hope that this setup will seal OK. I hope to have it assembled tomorrow and take it for a test run. I have to believe that going from a dished piston to a popup and then a gasket delete should make a difference in power....will be fun to see how much!

 

[RED-85-Z51]

.030"?

Sent from my LM-G820 using Tapatalk

 

[cuinrearview]

You measured correctly. I usually take .010 off of the bearing cup to set squish at .020. You will notice a difference with the added compression. If you can pry the muffler deflector up and open the outlet(assuming it's an empty can) as much as possible under the deflector you'll notice as much of a gain.

 

[cranman1951]

Thanks CU...I remeasured the squish and it came out to .023....I wasn't using the right technique with the calipers as the solder was fatter at the tip near the cylinder wall. I ended up cutting the entire plastic clamp off of the intake manifold with a hacksaw and used the 372 clamp......so much easier! On the muffler mod, would adding a side pipe out of the can be beneficial, or just stick with opening up under the deflector? Also, would another carburetor from a bigger saw give any worthwhile gain? I'm guessing that the carb adjustments can provide more fuel if needed.

 

[cuinrearview]

Without porting a bigger carb won't add anything. It will just make the saw more sluggish off idle. A second opening would work fine.

 

[old guy]

This is how I do em

 

[cranman1951]

Thanks Old Guy...I'm trying that today!

 

[cranman1951]

Latest up date on project 350/353 popup. I buttoned the saw up this afternoon, actually yesterday, but didn't want to start her until the Yamabond had cured some. She started right up and didn't need much in the way of carb adjustments...I had taken off the limiters already. I used Old Guy's muffler mod technique, the 372 xp intake clamp on the stock modified intake manifold, the Hyway 353 popup piston with the stock 350 45mm cylinder, gasket delete, 023 squish, and a modified 346 xp muffler brace. I won't know how much gain I got from the modifications until I put her to some wood, but my initial impression is that she has much faster throttle response...maybe it is just the sexy throaty sound of Old Guys muffler modification. With out porting, I think I've gone as far as is practicable with this platform, so I'm going to start putting pieces together for a 346xp /350 hybrid......no reason except I'm curious. I'm very happy with the 350 in stock form, so I doubt I'll be disappointed with the hybrids...LOL. Thanks for all the help and advice from everyone!

 

[cuinrearview]

You can use a dremel or even a cordless drill with some metal cutting bits and sandpaper to open up if you change your mind. The jug on your saw is one of the easiest for small time hacks to port.

 

[cranman1951]

Thanks CU...I'll be in touch ...

 

[Joseph W Santora]

This is how I do em

Any special reason you chose to cut the slit in the back part of the muffler and not more towards the front?
Joe

 

[cranman1951]

I just noticed that "oldguy" made the cut in the back half of the muffler....I thought I copied it, but I made my cut in the front half...maybe on the next one I'll move it back to see any difference.

 

[old guy]

Any special reason you chose to cut the slit in the back part of the muffler and not more towards the front?
Joe

If they have a baffle you need to cut behind it.