Ported Saws... Lets see your work fellas

Ronie

Ronie

Well-known member
Local time
6:49 AM
Joined
Sep 12, 2021
Reaction score
277
Location
NC
Mastermind said:
Sounds too lean. I'd imagine that is making it too hot and causing the running on. Personally, I like em fat. LOL
Click to expand...
Yea, it is to lean. I'm not leaving this cylinder on it so I figured I keep leaning it until I got to the fastest it would cut, I didn't really care if I messed the cylinder up. I probale cut to much out of the band, I had it on and off the lathe so many time and lost track of how much I cut, I know I had to cut .080 off the base to get the squish to .019. It has a lot of compression and maybe that is causing a lot of heat. I'll go out and make a short cut with it and see if it still does it, that way it doesn't have time to get to hot.
 
Mastermind

Mastermind

Active member
Local time
5:49 AM
Joined
Sep 12, 2021
Reaction score
191
Location
Banner Springs Tennessee
Ronie said:
Yea, it is to lean. I'm not leaving this cylinder on it so I figured I keep leaning it until I got to the fastest it would cut, I didn't really care if I messed the cylinder up. I probale cut to much out of the band, I had it on and off the lathe so many time and lost track of how much I cut, I know I had to cut .080 off the base to get the squish to .019. It has a lot of compression and maybe that is causing a lot of heat. I'll go out and make a short cut with it and see if it still does it, that way it doesn't have time to get to hot.
Click to expand...

Too much compression will make one get leaner and leaner the longer it runs. I'm interested in your test results.
 
Buxton_Work_Saws

Buxton_Work_Saws

Member
Local time
6:49 AM
Joined
Sep 15, 2021
Reaction score
86
Location
US
Ronie said:
It might, I'm going it check in a bit.

Here's the numbers I used.
Click to expand...
Them numbers look perfect for a 361.. I'd say it's too lean .. like said above or you have a aftermarket carb issue. Some of them aftermarket carbs are real bad.. I've had them do simulator or you tighten the dang jets up tight and they are still fat... I'd say it's pretty safe to say it's not porting it's a tuning or carb issue.

Sent from my Pixel 4a using Tapatalk
 
Ronie

Ronie

Well-known member
Local time
6:49 AM
Joined
Sep 12, 2021
Reaction score
277
Location
NC
Mastermind said:
Too much compression will make one get leaner and leaner the longer it runs. I'm interested in your test results.
Click to expand...
So I before starting it I turned the H around 1/16 of a turn richer, started it and then turned the camera on. It must be getting to hot when I've got it on the edge, it's faster like that but that won't do me any good if it ends up scoring the cylinder. I don't know if the aftermarket carb comes into play here or not. When I checked the RPMs it was at 13,950. After making them cuts I pulled the back cover and sprayed the back of the cab with brake cleaner and didn't have a leak so that eliminates that. When the OEM carb gets here I'll put it on and see what happens.



 
E

EggShooterist

Member
Local time
6:49 AM
Joined
Sep 13, 2021
Reaction score
44
Location
Nunya
Nutball said:
That's probably my doing, I like to run them smooth where they feel like they cut best or fastest. The guys at the removal company I work at repetitively lean on them until they almost stall, let off, and repeat.

Just for fun experimenting with this farmertec kit ms250, and also to see how well JB weld holds up in a cylinder. I tried reducing the volume in the crank case by stuffing it with JB weld. Also added JB to the intake, and upper transfers to perhaps help the mix flow around the otherwise sharp corners, similar angle to what the Echo 490 & 590 have. I'm not sure if it helped, but the saw runs well. It definitely needs a lower exhaust port and higher compression.

Below, one side of the lowers setup, about to fill the other, but before smoothing and clearancing for the piston.
View attachment 565

No time spent purtying up the exhaust port, just hogged it out a lot.

View attachment 567


View attachment 568


In the video I was testing the stock muffler on it because the one I modified to exit out the front felt like it may have lost some low end torque, but gained a little high end torque. Even though the ms250 seems to have a lot of cooling surface area compared to other saw engines, it starts out quite sporty when cool, but after 5min or so of non stop firewood cutting, it seems to slow down a lot.

First cuts, not broken in yet, still tuning during that session. I attribute the low end torque to the raised and widened intake. I might leave the intake lower on my second kit. Cedar, then Hickory.
View attachment 566
Click to expand...
Drop the vid of the 2511 with 20" bar lol.
 
BigSachsDolmar

BigSachsDolmar

Member
Local time
5:49 AM
Joined
Sep 9, 2021
Reaction score
54
Location
Wisconsin
The dragon 🐉 finally getting some love
 

Attachments

  • 20210922_225136.jpg
    20210922_225136.jpg
    3.2 MB · Views: 17
  • 20210924_174634.jpg
    20210924_174634.jpg
    1.2 MB · Views: 16
  • 20210924_194710.jpg
    20210924_194710.jpg
    1.2 MB · Views: 17
I

Iroczu

Member
Local time
5:49 AM
Joined
Sep 10, 2021
Reaction score
49
Location
Winnipeg manitoba canada
Mastermind said:
When I had a few hundred saws under my belt, I thought I had a lot of this stuff figured out. I would do a lot of build threads, and post a lot of videos. I shared my knowledge freely. I wouldn't necessarily say the information I was sharing was all wrong, but it wasn't all as accurate as it could have been either. The thing was that as I learned more, I realized that some of the stuff I thought I knew wasn't as true as I thought it was. In other words, the more I learned, the less sure I was about sharing. The problem is, there are so many different types of saw engine, that there is no certain recipe that applies to them all. For instance, the Husqvarna 5 series is a strato engine with really long transfer tunnels. It uses a very short blowdown time. The Stihl 201, 261, and 362 are also stratified but have short tunnels, and use a longer blowdown time. Rather than just grab a set of numbers from someone else's build thread, we should all be trying to figure out why these engine designers used the timing numbers that they did. Another example, using non-stratifed engines: The Dolmar 7900. Really tight transfer tunnels, and pretty small ports for an 80cc saw. This saw is designed with a long blowdown time. About 26° or so. The 7900 is a quad port design. The Stihl 046 has a two port design, wide open transfer area, and employs a very short blowdown time of about 14 - 16 degrees. I encourage everyone to study these different designs and try to figure out why they use such widely varied port timing numbers rather than playing follow the leader on their builds.
Click to expand...
As the saying goes, the more you know the less you actually know when it comes to this stroke porting game. I did a really wonky thing on the intake port on the 026 and it for what ever reason made a night and day difference
 
Fabz

Fabz

Active member
Local time
6:49 AM
Joined
Sep 13, 2021
Reaction score
127
Location
Buffalo Ny
Husqvarna 572xp Hotwoods Torque port and a STIHL 462c Hotwoods port with K/N filter and machined intake. Looks like the STIHL (72.2cc) took the Husqvarna’s (70.7cc) lunch money. With some intake work I can make the Husqvarna quicker but I’m loathe to mess with it as it’s a damn good stock filter setup. The stock STIHL filter situation on the other hand isn’t so great ...
 

Attachments

  • IMG_2320.MP4
    2.9 MB
  • IMG_2319.MP4
    3.4 MB
Last edited:
Nutball

Nutball

Active member
Local time
5:49 AM
Joined
Sep 14, 2021
Reaction score
190
Location
Mt. Juliet, TN
572 seemed quieter and didn't appear to get leaned on as hard. Maybe that's why it was a little slower? Looks like a similar muffler mod on the 572, so I don't know why it is quieter. Quick chain though on both.
 
You must log in or register to reply here.
Top