Spuds Porting and Tuning Thread

[spudulike]

Do they make high discharge clutch covers for these things?

 

 

This thing is crazy, and I would consider it mildly ported. Granted, I took a lot of advice from some good builders, but it's amazing what this thing can do with just a bit of a tickle. I think removing the baffle it the key. Unfortunately, it is also the key to noise.

 

Sounds a little fast!

 

Been porting a big ole 088 Stihl today, think it is a fair bit lighter now with the amount of aluminium I have taken out of it!

 

Not tuned it yet but should go a fair bit better now!

[lurcher4]

Lol I'm not aloud saws, I just look at them 28 stitches! Sounds sore

 

did sting a bit but dident bleed as much as I thought it would chain must of been sharp lol:thumbup:

[mendiplogs]

Well, here it is at long last. Some of the guys on my other "Whats on your Bench" thread aren't in to porting so thought I should split out this type of chainsaw modification for those with similar interests.

 

Personally, I got fed up with just repairs and did a blokes "I wonder what would happen if....":001_rolleyes:

 

I purchased three 346XPs, two were for resale and the third......got ported and I never looked back - the results of the porting sounded and felt great so the porting bug stuck.

 

Currently I am working on an old 066 that will be a real beast once done but that will appear soon.

 

Today it has been MS441 tuning, the ring end runs down the side of the exhaust port messing up any chance of widening it unless you want a lop sided port and uneven blowdown:thumbdown:

 

The saw is a strato so left the porting and recommended just a simple muffler mod - I had two diameter pipes I could have used, a simple hole would have a similar effect but like to make the finished job look good so chose the smaller of the two.

 

Good thing I did as it is suitably loud. I also openend up the existing hole. Pickup is faster now and am happy with the look:thumbup:

 

So Gents, a start of what will hopefully be another great thread:thumbup:

Hi all anyone out there with a ported 660 thanks Jon

[wyk]

Yes, pn 1122 648 0401

 

Obliged.

 

Why am I not surprised. I'll pass that on to the owner.

 

I got to say this new fangled MTronic business really knows how to run a saw. You don't get anywhere near the gains I did when you put that work in to a standard non MT saw. Unfortunately, it makes it a lot less fun to tear into them and mod them. It's all fiddly now. But I guess at least ya don't have to play with the timing.

[spudulike]

This weekends project is porting a MS360, I have had the timing wheel on it: -

 

Exhaust duration - 162 deg

Inlet duration - 150deg

Transfer Duration - 125deg

Blowdown - 18.5 deg

 

The blowdown is surprisigly low but have noticed that the transfers are at different heights so need matching.

 

The squish is over 1mm so the base gasket needs dropping out.

 

I will widen and re-shape the inlet and exhaust ports plus drill out the muffler outlet and braze in a much bigger outlet pipe.

 

Inlet duration seems fairly long so won't extend that. Dropping the base gasket will make it a few degrees longer!

 

The exhaust port seems pretty low - as low as an 088 I did a fortnight ago - may raise it a little to make up for the lowering of the squish.

 

It should go a fair bit better once done:thumbup:

[adw]

I would be intrested to know what this porting does to the fuel consuption, longevity of the engine big end and side bearings, noise levels, emmisions, vibration,chain speed ( do they now need higher class trousers ) not knocking it just intrested.

[spudulike]

I would be intrested to know what this porting does to the fuel consuption, longevity of the engine big end and side bearings, noise levels, emmisions, vibration,chain speed ( do they now need higher class trousers ) not knocking it just intrested.

 

Fuel consumption goes up - you get nothing for free

 

Longevity - seen no detrimetal signs to date, some have had three years on my ported saws and they were far from new when I did them. Some have been used hard from what I can tell.

 

No big end or crank bearing failures to date - generally the bottom end is a lot stronger than the piston/cylinder

 

Noise levels are increased - thats the nature of the beast - same as race bikes

 

Emissions - no way of measuring but would think that they increase but won't polute as much as a 737 off to Spain!

 

Vibration - no reason to increase

 

Chain speed - I usually tach to 500rpm lower than SPECIFIED max, sometimes close to max if the engine is still fourstroking heavily. Chainspeed will not be outside of design spec.

 

Chain speed will be significantly higher in the cut though - that is the gain you get.

 

Operators PPE - I build engines - if it was a racing bike, I would not get involved with the type of leathers or helmet the rider uses. All I do is give a saw owner a faster machine and test the chainbrake for correct operation and fit a new chain catcher if missing. The owner should have enough respect/training/common sense to take the correct actions in regards to their own safety.

 

Hope this feeds the fascination:thumbup:

[adw]

Thank you for that, as long as the owners are aware of some of the negatives to this practice, there is an old American saying, there is no substitute for cubic inches. I guess as long as people are happy with this then carry on.

[spudulike]

Thank you for that, as long as the owners are aware of some of the negatives to this practice, there is an old American saying, there is no substitute for cubic inches. I guess as long as people are happy with this then carry on.

 

The owners seem pretty happy, I think all the drawbacks have been discussed at length in this thread and others.

 

One of the real live reasons for having this work done is the abillity to grab a 60cc saw and have it cut at close to the speed or faster than a 90cc one on a similar bar length. This will stress the body much less and cause less fatigue and cut the risk of accidents.

 

Your comment about CCs kicks in when a 3' bar is strapped on rather than a 18" one - for real big stuff there is no real alternative than big CCs!

 

I did ths work for my own interest and then others showed interest in what I was up to and once a few pros had savoured the work.......it got a bit more popular.

 

I never force guys to have their saws modded, I actually spell out the drawbacks and potential issues and get them to think about these mods in a sensible grown up manner rather than the laddish Whoooaaarrrrrrr sort of way. After that, it is their choice as adults!

 

I personally run a few ported saws and they do give an enhanced pleasurable experience in use but that is my own view that others share.

 

Each man to his own, some love it, others show no interest!

[wyk]

Oh, but this American thinks there IS a substitute for cubes.

 

 

It takes my ported 044 to beat that monster in that wood:

 

https://www.youtube.com/watch?v=K-uMkEhRNAE