Saw Modz

I built one with a cut squishband, but otherwise the same, and it was not as strong or fast. I think the much taller transfer ports might hurt performance. Using a popup doesn't not alter port timing like cutting the squishband does. I consider that to be a good thing. However, there are saws, such as the MS660, that need the squishband cut to make a great runner. One recipe doesn't fit all saws. Use what works.
 
At this point all I'm capable of is the muffler, finding ways to introduce more air into the air box and thanks to your advice advancing the timing. So I guess my question should have been: do they respond well to those mods without porting? We've got another rainy day with 40 mph gusts here so unless I get some storm damage I've got time for some saw work.
 
@Jackjcc, I got my 338xpt modded and it's running great. Just want to make sure that I have it tuned right. What should the tach read at idle and full throttle? I'm getting 3600 at idle and 11500 at the top end...

Reed Wortley
CTSP #01739
ISA CA #SO-6953A
 
Usually 2800 for idle. After muff modded the top end should increase by some over manufacture recommendations. Each saw is different so you just need to make sure it 4 strokes out of the cut and cleans up when cutting. I can't find the max rpm for saw, husky list the max rpm for power as 9600, but that is under load.


Sent from my iPhone using Tapatalk
 
Jackjcc said:
Usually 2800 for idle. After muff modded the top end should increase by some over manufacture recommendations. Each saw is different so you just need to make sure it 4 strokes out of the cut and cleans up when cutting. I can't find the max rpm for saw, husky list the max rpm for power as 9600, but that is under load.


Sent from my iPhone using Tapatalk
Click to expand...
So, you'd say my idle is high then?

Reed Wortley
CTSP #01739
ISA CA #SO-6953A
 
Yeah, that should be pretty close to where the clutch will grab and you don't want that thing turning at all if it's on your saddle. Idle tuning took me the longest to get figured out. 4 stroking is easy to figure out, setting the idle, low, and high correctly to get smooth acceleration and deceleration was a struggle.


Sent from my iPhone using Tapatalk
 
Jackjcc said:
Yeah, that should be pretty close to where the clutch will grab and you don't want that thing turning at all if it's on your saddle. Idle tuning took me the longest to get figured out. 4 stroking is easy to figure out, setting the idle, low, and high correctly to get smooth acceleration and deceleration was a struggle.


Sent from my iPhone using Tapatalk
Click to expand...
Thanks mate!

Reed Wortley
CTSP #01739
ISA CA #SO-6953A
 
Hey guys, I recently rebuilt the top end on a ms 650. I did tho put a NWP big bore kit 660 on it instead of the 650. I did get a bigger jet for the carb to allow more fuel. I have run 5 or more tanks through it already. It doesnt have the power i thought it would but im afraid to lean it out to much. Would a size 70 jet be to big for this set up?
 
The big bore kits are not known to always produce more power. The port timing may be off and the power never fully realized. Is the power now noticeably than the 650 top end?


Sent from my iPhone using Tapatalk
 
I don't know about that. Too much fuel kills power. You should work on getting it tuned in wood. That will get you closest to max power.


Sent from my iPhone using Tapatalk
 
Jackjcc said:
The stock filters are great on the new mtronics. All the adjustments you make will be accounted for automatically by the "computer." If you open the muffler and increase airflow, the saw will compensate.

There is some speculation that the 661 may be limited for the few half dozen tanks of fuel. A lot of people have reported that its like a switch is flipped and the saw seriously opens up. So if your 661 is still new, you need to get 10 tanks of fuel through it before you need to be concerned.
Click to expand...

Here ya go Jon...did this with my 661 when new...carb readjusts...it rips a mean one....starts easy...2016-04-26 19.18.12.webp
 
TJG said:
I have a 192 it doesn't have any snap getting up to speed is slow What type of gains did you notice with your muffler mod?
Click to expand...
Try a muffler mod ; timing advance and a sharp chain ... I am available for saw upgrades ... have videos showcasing work .... email Fabz2@me.com .... after "massaging" the saw u can expect up to 40% faster cutting ... if more Performance is desired the combustion chamber can be modified and porting done
 
You must log in or register to reply here.

New threads New posts

Kask Stihl NORTHEASTERN Arborists Wesspur TreeStuff.com Teufelberger Westminster X-Rigging Teufelberger
Back
Top Bottom