Spuds Porting and Tuning Thread

[spudulike]

Trying sumfin new. Instead of putting bank into a lightweight 24" Sugi(which is well over a 100 Euro or so by the time it lands on my shores), I went with a 60 Euro delivered 25" Rollomatic E. It weighs nearly what a Sugi lightweight does. It won't last quite as long, but I still usually get a few years out of them.

 

Here she is on the 361R, 84DL 75JGX full skip Oregon chain. Oiler isn't even turned up yet and she still oils well(old style oiler holes as this is a NOS Rollo E - '5321' series, I think). I still need to replace the impulse line as this one is set up for the old 044 carb she used to wear, so not as responsive as I would like out of this size ported saw. I found with the 044 carb there was not much difference in power on the typical bars and RPM's I use a saw with, only a difference in fuel

 

MS361 ported in Beech with 25" bar - YouTube

 

 

Looks like it pulls pretty well Wes, good job:thumbup:

[burrell_]

My 372 runs like that cuts like bill oh

[spudulike]

My 372 runs like that cuts like bill oh

 

And why is that Martin:sneaky2:

[burrell_]

Because it has a 24 inch bar no idea

[burrell_]

Or it may just have a little bit to do with the fact u ported it :thumbup:

Another top job spud

[spudulike]

Or it may just have a little bit to do with the fact u ported it :thumbup:

Another top job spud

 

Ah yes, I remember now:sneaky2:

 

Glad you are happy with it - a tried and tested mod now!

[wyk]

Ah yes, I remember now:sneaky2:

 

Glad you are happy with it - a tried and tested mod now!

 

Judging by his avatar, he is REALLY happy about it!

[spudulike]

Judging by his avatar, he is REALLY happy about it!

 

Does look that way doesn't it:001_rolleyes:

[spudulike]

Been porting a MS660 this weekend, the figures

Exhaust duration - 170*

Inlet Duration 158*

Transfer Duration 112* ......yup - had to check this a couple of times

Blowdown - 29*

 

There are many restrictions in the MS660 - the exhaust port can't be widened by much so settled for reshaping the profile, the inlet again can't be widened by much so again reshaped it. The uppers can't be taken back by much due to the ring ends so settled to reducing the blowdown figure to 24.5* which gives a longer time the transfers are open so more fuel charge:thumbup:

 

The lower part of the lowers had the ridge removed and blended in to the cylinder wall.

 

The piston windows were opened and flowed plus a few changes to the muffler to get it breathing.

 

Be interesting to hear how it performs - there are some mighty big differences in the MS660 figures to the older 066 - the exhaust port ceiling is lower giving a lower power band, the blowdown is significantly shorter on the 066 and inlet duratiion longer - all very interesting but the changes I have made should give significant gains.

 

I also extended the exhaust outlet to stop the bendy handle issue that some have reported on this site:thumbup:

 

The squish came out at 0.65mm so nothing much to do here so left alone.

[NFG]

Trying sumfin new. Instead of putting bank into a lightweight 24" Sugi(which is well over a 100 Euro or so by the time it lands on my shores), I went with a 60 Euro delivered 25" Rollomatic E. It weighs nearly what a Sugi lightweight does. It won't last quite as long, but I still usually get a few years out of them.

 

Here she is on the 361R, 84DL 75JGX full skip Oregon chain. Oiler isn't even turned up yet and she still oils well(old style oiler holes as this is a NOS Rollo E - '5321' series, I think). I still need to replace the impulse line as this one is set up for the old 044 carb she used to wear, so not as responsive as I would like out of this size ported saw. I found with the 044 carb there was not much difference in power on the typical bars and RPM's I use a saw with, only a difference in fuel

 

MS361 ported in Beech with 25" bar - YouTube

 

Hi,

 

Nice saw that, some pretty rapid cutting & the mandatory full wrap handle too, got to say I really enjoy this thread.

 

well done all, some excellent work here.

 

N

Edited March 2, 2014 by NFG