Hack and Slash Saw Mods!

[Crofter]

Have we been seeing some examples and recipes lately? Tools used for modification can be pretty basic; after all modification only means making the thing different. Your axe will do that! Now improving something takes a bit of thought and some idea as to what it is that needs to be different.

Do you need a systematic approach? Simply hacking away metal is a good recipe for disaster. Starting out with blancket approach ideas like, "increasing exhaust duration is good, or trimming piston skirts is bad, or increasing transfer area is good" etc. is purely sh!t luck. Why? Every engine has its own particular characteristics. Bore to stroke ratios present different scenarios for example. Sometimes a particular bottleneck is built in to limit rpm. Other engines might have 4 bottlenecks ( or none! ) It is absolutely necessary to know what and where the limiting factors are. Simply making things bigger which do not present a bottleneck will most likely hurt your game. Unnecessarily extending exhaust or intake timing events will most definitely hurt your game. Remember metal removed is a bridge burned.

Some builders have the experience to quite quickly eye up an engine and make improvements, but experience also tells them that if they want to make the best gains without trial and error and scrap heap parts, they have to measure and calculate timing events and flow velocities from one end to the other of the engine. Then, and only then will they crank up their porting tools.

If you don't have the technology to do this analysis then you are only stabbing in the dark. Your success will be more like fortune telling than science, but it is amazing how many people just feel they are lucky souls.

 

[Freakingstang]

This is probably why I have not yet modded any of my saws....Although I do see a muffler mod in the near future lol.


Steve

 

[Stihl Crazy]

Frank, that is one of the most sensibly posts in the last few days. I play with my saws some and have had more failures than gains. When it comes to good saws like my 088 I send them to someone who understands what they are doing. My mistakes on a 088 would cost more to fix than the cost of a "pro" porting job.
____________________
Art

 

[DanManofStihl]

I wonderer the same thing all the people on here are doing the "Do it your self Muffler Mods". I see the pictures and it looks like they did nothing more then drill a few holes and now its modded. I sent mine to walkers saw shop and they cut and welded on it and made it look nice and professional done. It also was not that expensive to have it done. I would rather pay $35.00 then fry a $700 to $1600.00 saw. But thats just me

 

[trimmmed]

Some builders have the experience to quite quickly eye up an engine and make improvements, but experience also tells them that if they want to make the best gains without trial and error and scrap heap parts,
.

So how do you get the experience? Or are you saying the inexperienced should stay away from the hands on and just write a check?

 

[04ultra]

Go on E-BAY buy a dozen saws cheap . Get out dremil and make some junk . Its good for sellers and dosent cost that much . Plus with scrap prices high you can recover . and learn theory . OOps

 

[jokers]

So how do you get the experience? Or are you saying the inexperienced should stay away from the hands on and just write a check?

Hi Dave,

I don`t think that Crofter is saying that the inexperienced shouldn`t try, I think he is saying that the inexperienced shouldn`t attempt to portray themselves as experts and lead other inexperienced people down the rosey path to destruction, or atleast financial loss.

Crofter and Timberwolf have modified several saws that I`m aware of. It seems to be an ongoing learning process.

Russ

 

[Crofter]

I guess everyone has a different learning style but it usually reduces the trial and error if you have a bit of theory. That means reading. If you do want to experiment work on a low value saw that would be no calamity if you scrapped it ( it could and has happened). It is hard to have the discipline to properly control your experiments. Do you always do before times with a bar and chain on wood of a type and size you can duplicate afterwards to know whether you made more power or more noise? Make only one change at a time. Document, not trust to memory what you did.
Some people are empowered by trying things themselves and are rewarded by the game; go for it. Dont have any illusions that it is a matter of luck to make a winner. Know too that some things taken to the limits start to have tradeoffs. If you want fairly certain results and return for your time and money I think it is better to trust a saw to someone you are pretty sure is not working on the trial and error method.

 

[lucky]

Hi Dave,

I don`t think that Crofter is saying that the inexperienced shouldn`t try, I think he is saying that the inexperienced shouldn`t attempt to portray themselves as experts and lead other inexperienced people down the rosey path to destruction, or atleast financial loss.

Russ

Russ if one dumba$$ follows another down the path to ruined saws whose fault was it? Do those who follow posses no responsibility for their own action? Besides everyone must start somewhere and anyone who picks up a porting tool is going to ruin some stuff at first. But the smart ones will learn and won't repeat mistake made along the learning curve.

Frank, you known it's not too late to send Gypo a degree wheel for Christmas. You could just tell him its in the mail.

 

[Simonizer]

Have we been seeing some examples and recipes lately? Tools used for modification can be pretty basic; after all modification only means making the thing different. Your axe will do that! Now improving something takes a bit of thought and some idea as to what it is that needs to be different.

Do you need a systematic approach? Simply hacking away metal is a good recipe for disaster. Starting out with blancket approach ideas like, "increasing exhaust duration is good, or trimming piston skirts is bad, or increasing transfer area is good" etc. is purely sh!t luck. Why? Every engine has its own particular characteristics. Bore to stroke ratios present different scenarios for example. Sometimes a particular bottleneck is built in to limit rpm. Other engines might have 4 bottlenecks ( or none! ) It is absolutely necessary to know what and where the limiting factors are. Simply making things bigger which do not present a bottleneck will most likely hurt your game. Unnecessarily extending exhaust or intake timing events will most definitely hurt your game. Remember metal removed is a bridge burned.

Some builders have the experience to quite quickly eye up an engine and make improvements, but experience also tells them that if they want to make the best gains without trial and error and scrap heap parts, they have to measure and calculate timing events and flow velocities from one end to the other of the engine. Then, and only then will they crank up their porting tools.

If you don't have the technology to do this analysis then you are only stabbing in the dark. Your success will be more like fortune telling than science, but it is amazing how many people just feel they are lucky souls.

Excellent post.

 

[Gypo Logger]

Frank, could you explain why I am getting positive results from doing basic things to the engine?
Once again we are to assume your are the expert and trying to discourage others from getting gains.
Why don't you discourage others from filing their own chain as well?
John

 

[Simonizer]

Frank, could you explain why I am getting positive results from doing basic things to the engine?
Once again we are to assume your are the expert and trying to discourage others from getting gains.
Why don't you discourage others from filing their own chain as well?
John

Are you using a dyno to get quantitative results? Are you documenting everything you do? Are you making only one change per dyno run? These are all critical procedures.

 

[bikepilot]

In regard to getting experence, I know there are schools that offer high-performance two stroke building classes. I know a local engine builder (bikes & ski's) went to one years ago and found it very usefull. Dyno's and flow benches are usually found in most of the advanced two-stroke motorcycle engine building shops.

Personally, I'm not a pro engine builder, but I can make small improvements. On my race bikes, if I'm happy with the basic power spread of the engine I'll usually just polish up the ports, remove casting flaws and often make small changes to the port shape. Doing this has never hurt my performance nor does it make a slow bike fast. What it does is really nothing more than make the engine like the engineers would have liked it to be, but couldn't due to production cost issues. I've not taken a saw motor apart yet, but you'd be surprised how sloppy the castings inside a bike or ski motor can be sometimes.

 

[Simonizer]

I modify my saws according to how engineers would have liked to have designed them, had they not had to adhere to stringent emissions criteria. I am an engineer. Unlike these very capable professionals, my hands are not tied.

 

[Crofter]

John why are you asking me to explain the whys of what you are doing?

You make an assumption I am trying to discourage people from grinding up their saws. Not at all, just pointing out why it would be better to know the risks and consequences of what they are doing. There are plenty of incidents of pith poor results floating around AS from people cutting a bit off of this and that. It is not all good news bears remember. If I am throwing a bit of caution it is hardly adequate to balance your apparent enthusiasm for talking people to take a risk with their saws. Why have you suddenly become so helpfull at someone elses potential expense?
As to having people file their own chains, I think that is an excellent idea. You are only risking 15 bucks and if it is not good, file some more off. Not so painless if you have screwed up your saw.
All in all John, I think that the kind of haphazard tinkering you advise will be good for legitimate saw builders; it cant help but give them work!
While you are at it John, I think you should encourage people to do a cost/benefit analysis of what they are about to undertake. Good thing to do no matter what the task. Perhaps you just have not got around to yet covering potential pitfalls and I am being presumptous. My apology if that is the case, lol!

Remember momma used to say, Quit while you're still having fun!

 

[HELSEL]

Crofter , How this E.J. remember!!!!


Rick

 

[Crofter]

Crofter , How this E.J. remember!!!!


Rick

You mean this guy! Meanhusqvarna? http://www.arboristsite.com/showthread.php?t=13462

Sure, tell him the guys will know a bit more about alcohol saws next year. Ask him if he remembers they stop the clock here when the saw gets back on the ground.

 

[jokers]

Frank, could you explain why I am getting positive results from doing basic things to the engine?
Once again we are to assume your are the expert and trying to discourage others from getting gains.
Why don't you discourage others from filing their own chain as well?
John

Well Gypo let me preface my statements with what the hell do I know, but the reason that I think your are seeing positive gains with your basic techniques is that you are on the right track for what needs to be done, I just don`t always like the path you take to get to your objective. I think that you are much smarter than you are portraying yourself as in the saw mods thread but that you simply have an agenda.

In the end, it doesn`t make you look good.

Russ

 

[jokers]

Russ if one dumba$$ follows another down the path to ruined saws whose fault was it? Do those who follow posses no responsibility for their own action?

Lucky,

You know me well enough to know that the last of those statements couldn`t be true as far as I`m concerned. But should well known and possibly respected posters be giving people bad ideas?

Russ

 

[lucky]

Russ, the short answer is no, possibly respected posters shouldn't be spouting off bad ideas but then again to reference gypos latest thread to which I believe you infer, he raises the exhaust 1mm and clips the piston by 2mm. I don't think that is going to kill his saw. Without having the saw in my hands I cannot say by how much the numbers where changed but my guess would be that he hasn't gone too far. I doubt those methods are optimal for that saw but then again the title says "basic saw mods"
A thread such at this gives newer members some idea to what goes on. I would hope anyone inspired to perform surgery on their own saw would also understand they do so at their own risks and the possible negative outcomes. Don't you think most people understand this?