October 12

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5 Steps To Woods Port A Chainsaw For Power Gain (Up to 25%)

In this post, you are going to learn how to woods port your chainsaw that will result in up to 25% power gain.

...and all it takes only 4 easy-to-implement steps.

These are the exact steps I follow to wood ports my chainsaws and got 10%-25% power gain.

Why 10%?

Because the exact result cannot be guaranteed every time before.

...and it depends on a few things too.

If woods posting seems risky to you, I have good news for you.

On the 5th point, I have added a guide of “Light woods porting” for beginner chainsaw operators...

...where I discuss less risky alternative methods.

Any newbie can implement it.

today I’m going to show you how I do it…

…and how you can do the same thing.

Sometimes, you may need more power than the stock power from your chainsaw. Here comes the need for chainsaw modification.

There are tons of methods to modify the stock chainsaw engine and increase horsepower(HP) and torque. Woods porting is one of them. 

The key idea is to make the chainsaw breathe better and smoothing out the exhaust system.

After woods porting, you will experience a higher WOT(Wide Open Throttle) RPM. The speed will be at the max of factory specs, or even higher. It is less radical version than race porting.

In general, wood porting is done on work saw or pro saw that run all day in the forest.

What is woods porting?

The basic idea is very simple. In wood porting, all you need is to make a few changes to the chainsaw engine such as rejetting or replacing the carb, changing the cylinder head shape, tweaking port timing.

It allows more gas flow which helps to get higher compressor ratio.

Thus it results in more power to the engine. It impacts on response time, torque and power curves. In short, it increases engine performance.

To give you an idea, a comparison between a stock Jonsered 490 and a ported Partner 5000.

The piston and cylinder type is the same on both chainsaw. I used 325 stihl RS chain on Jonsered 490 and 3/8 stihl RS on ported Partner 5000.

The same type of piston and cylinder is used on both saws. Now the 490 only has 325 stihl RS chain and the 5000 pulls 3/8 stihl RS.

One more thing to add, if you are a homeowner, you might never need to woods port your chainsaw. It would not be a great deal for you to spend extra 20-30 minutes in cutting as you would do it once in a week or month. For such people, I think it is better to pick a chainsaw with great maneuverability than woods porting it.

How to do woods porting?

Here are a number of things you could do for woods porting your chainsaw. Here are some of the ideas –

1st: Enlarge the Exhaust

Exhaust path is the gateway to reach the chainsaw's insider part. That's why you have to enlarge the exhaust pipe/path.

First, Open up the “muffler”. If you don't know how to do it, watch a few videos on YouTube. You may need to use a grinder, drill or any other machines based on your chainsaw model.

Take a close look at the intake and exhaust port. Enlarge or widen the ports using power tools you use earlier.

After widening the exhaust path, ensure it is wide enough to fit your hands.

2nd: squishing

Squishing is another way to do woods porting. All you need to do is to lower the jug of the saw. You can use a thin gasket or do milling to make the changes. It also increases the compression ratio and power.

Step 3: A few more tweaks

After doing the above two steps, you will experience a better compression ratio from the engine. Most saw owner finishes their woods porting process at this stage, but you can modify a few things more for even better performance.

  • Modify the transfer ports of the compressor.
  • Change the ports' mechanical timing (by grinding and polishing)
  • Remove excess material from the piston and make it lighter
  • Remove RPM limiter coil or change the coil out to a non-limited type
  • Polish the piston ports under the skirts

By doing the above things, your saw engine can get another boost in the compressor ratio.

Step 4: Using sawdust (Irregular manner)

The above 3 processes are regular methods and considered safe. There are some other methods of woods porting which can improve compression and increase engine power.

One of them is a process using sawdust. Take some sawdust and fill out the combustion chamber. It results in a boost in combustion ratio which makes the saw engine more powerful at cutting.

Your chainsaw will work with more power due to the high compression ration.

But there is a problem. In this process, the heat cannot be reduced. It does not reduce the temperature in running which is one of the main purposes of woods porting. More heat means more wear which will damage the chamber in the long run.

Light woods porting (Less Risky alternative methods)

If you feel the above process risky and don't want to take many risks, you can do light woods porting. You can do:-

  • Light port grinding for better engine breathing
  • Shave the jug down just a smudge
  • Open up the muffler to original stock design or a bit more
  • Tune the carb richer

Apart from these, there many ways to increase the stock power such as removing spark arrestors etc.

Cautions

You have to treat the transfer ports with proper care and respect. If you are not familiar with the process, watch a few videos on YouTube or manage a mechanic for supervision. if you mess up the ports, you can damage the mechanical timing.

To raise the compression, Some people pull the jug gasket from the saw. Others thin it and put in a Bud can gasket.It would be far better if they replace the rings.

Some people make exhaust ports too wide. Never widen the ports so much that can clip the rings. Some  Stihl users do this mistake.

Doing woods porting incorrectly can reduce the engine power and even damage completely in some cases. I have seen many ported saws that cannot cut when WOT.

Note that every chainsaw is not compatible with woods porting. You cannot apply woods porting to some chainsaw models. You cannot squish the chainsaw which has clamshell engine. If you buy an expensive chainsaw for long time use such as Husqvarna and not sure about the risks, you can keep it as it is. 

For example, the Stihl 1123 and Stihl 1127 line of saws. However, instead of woods porting, you do the below things for increasing power.

  • Mod the muffler
  • Widen and polish the ports
  • Re-tune the carb

muffler mods in woods porting

Muffler mods help to move the gasses better for a ported chainsaw. Here, woods porting can be done in different stages. You can skip or stop at any stage you want.

  • Open up and/or gut muffler and/or remove CAT muffler and re-tune carb
  • Open up and polish cylinder ports
  • Turn down cylinder base and the outside of the piston crown
  • Open up and/or polish Transfer ports, lighten/polish piston
  • Rejet or swap out Carb with a bigger carb
  • Add A non-limited coil at any time.

Benefits & Risks: Is it worth porting?

Benefits

Woods porting reduces the back pressure on the muffler. If you do woods porting and retune the carb, you will experience the below things on your chainsaw. Your chainsaw will:-

  • Run better
  • Run cooler. Low operating temperature ensures less wear
  • Increase the longevity of usage
  • Increase the compressor ratio which can result in more power and better performance of the chainsaw.
  • Increase reliability
  • The saw can BREATHE better with the modification

Note: There is a misconception among many chainsaw operators that woods porting can decrease the reliability. But it is wrong. If you can do it the right way, you will get a more powerful chainsaw with more reliability and life expectancy. It plays a positive role in engine function.

Risks

Woods porting will void the warranty. If you do any mistake in woods porting the saw, it will be lost forever.

There is no guarantee that the builder you hire will be successful. Many builders create some odd-ball saws that just do not have the power desired from a ported saw

Lastly, even with a good ported saw, you cannot expect a good price if you want to sell it. In most cases, a modified saw will not gain any value on the market.

Final words: What I can say, it is up to you whether you take the risk or not. A perfect ported saws can deliver better power and response. They outlast their stock cousins in many ways.

Lean saws run hot. The heat builds up on the cylinder wall below the exhaust port. Running hot can lead to engine scoring. Ported saws do not run as lean saw.

Should you do it?

We all know time is money. But does this come into your mind when you are in running the saw?

if yes, probably you make a living off of your chainsaw. Since you are a professional chainsaw operator, you need to do a lot of cutting per day.

The more power you saw can deliver, the easier and quicker your tasks will be.

A timber faller once told happily how much more production he took in on a day when using his woods ported saws.

Although woods porting is not a Homeowner thing, but I know a few homeowners who did it. Their saws are still running as good as it was long before.

Some do it for occasional heavy-duty cutting such as felling trees and some did it when they are not happy with compressor ratio.

My Dad bought a Mac in 1980 which stills starts with 4-5 pulls and runs as powerful as it did 40 years ago. It still runs better than the other contemporary model.

Doing yourself vs. hiring someone

Hiring Builders/mechanic: A to Z

No matter how good or reputed the builders are, only inconsistency is guaranteed for woods porting service.

Choose your builders with much care and after proper research. Keep in mind that the gains from the ported saws will be different based on builders' expertise and experience. Don't be fooled by the hype. Hype cannot make any builder good at woods porting.

In most cases, the turnaround time is horrible. I have dealt with a good number of builders including local builders and some from online communities such as forestryforum.com and arboristsite.com.The average turn around time is 6-8 weeks and sometimes it takes several months.

Most people just go to a mechanic to "upgrade" the stock saw to a newer version without knowing much. Woods porting is costly and may need up to $500.It is not a small amount and even worse you may not get what you pay for if you do not get the "right" mechanic.

Tip: if you do not get any reliable mechanic in your area, search online for a remote mechanic. Shipping back and forth isn't cheap and might force you to spend a bit more money.

Due to customs duties and taxes, you may not be interested in using UPS. But compared to the lifetime earning of this saw,  a few dollars on shipping is not a big deal.

Doing yourself: The basic

Woods porting is of the box practice. Similar to cutting with a chainsaw like a pro, it needs a lot of expertise, experience, and knowledge to successfully do it. if you are not familiar with modifying chainsaw engine, you should stay away from woods porting until you learn more.

Needless to say, you should have good knowledge of how the chainsaw engine works. You also need practical experience modifying minor things before proceeding to a major modification. I suggest you start with light woods porting mentioned earlier.

Even after acquiring much knowledge and experience, you need a plan of action to do it properly. It will be better if you can manage a skilled mechanic to supervise you.

Otherwise, there is a high chance of damaging the chainsaw forever. In some cases, you cannot even go beyond repair.

My experience and results on woods porting saw

I do from mild muffler mods to full port jobs based on the chainsaw build. I get 10%-20% performance gain on average.

On a stihl 310, I just opened up the muffler and re-tuned the carb. I got a 10% gain. It took almost an hour.

On stihl 044, I added an 046 factory dual port muffler cover and retuned the carb. I got similar results which are 10% power gain, but it only took 15 minutes.

On stihl 066, I added a custom dual-port cover, retuned the carb, and replaced the rev limiter coil. I got between a 15-20% gain from that one.

why companies do not port their saws

If done correctly, there are no disadvantages of a ported chainsaw and it will work better than its stock counterpart. You may now think why the brands/companies do not port their own chainsaw?

The answer is US EPA laws. Since they must follow the laws and regulations to run business in United States, they are forced to follow some guidelines by the laws.

You may be surprised to hear that some brands make saws with wider ports but they are not sold in the USA. As an example, Stihl 290,310,361 and 390 saws have more open mufflers and richer carb settings.

In some cases, their wider ported saws have become choked up over time. This happens due to Federal EPA (and California state) regulations.

A good example of this can be Stihl 026/260. The early model had wider ports and fully tunable carbs. Now they are forced to make ports smaller and add internal baffles and caps limiters. These are done so that you cannot enrich the stock easily.

Apart from the brands/companies, dealers cannot even modify a chainsaw by law. Otherwise, they have to suffer from EPA penalties.

Last year, The EPA warned dealers about doing modifications. Chainsaw dealers often get flyers and notices as a warning.

However, the chainsaw owner is exempt from it. They have no restrictions or limitations by-laws

Wrapping up

The chainsaw is one of the most used power tools among trees and woodworking professionals. It is also very popular among homeowners too who have a big property to manage.

With woods porting you can take your chainsaw's engine power to the fullest and get the maximum value from it.

However, do not forget the risks associated with woods porting. One single mistake can make your chainsaw nothing but a toy.

About the author

Chris Ross

My name is Chris Ross. I'm an arborist by profession & a blogger by passion.Currently I live in Austin, United States. Being in the cutting services for more than 10 years, I know a thing or two about chainsaw. I love to write about chainsaw for homeowners and professionals. I hope my epic guides will help you to choose,buy and maintain chainsaw.


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