Where’s the best place or way to increase performance with a chainsaw.

[John_Mc]

90 octane ethanol free and 90 octane with ethanol is still 90 octane. It makes no difference. If your saw calls for 90 octane, use 90 octane. If you mess with the porting or timing and that causes a predetonation, higher octane may help with that. The only concern with gas with ethanol is storage long term. If you empty your saw after usage and don't let it sit for months at at time, you'll never have ethanol related issues.

Good advice. Also, too many people equate more octane with more power. For a stock saw that recommends 90 octane gas, going to 93 octane, or burning 100 octane leaded avgas will NOT give you more power. Those fuels aren't needed unless you are running a highly modified saw (usually one with a higher compression ratio).

 

[FredH]

Arborsite or YouTube are good places to start . I did a simple muffler mod as was describe previously , although I left in the spark arrestor . Like adding headers to a car , by aiding in the removal of exhaust , engines usually run better with a uptick in performance .

My saw is a 441 magnum , 25" bar and full skip chain cutting either oak or another northwest hardwood madrone / laurel . I seen a slight improvement in throttle response . Does not " bog " or hesitate like it did new .


Fred H.

 

[ericm979]

what is the easiest most fail proof way to adjust a carb.

Get a good quality inductive tachometer made for chainsaws and a copy of the shop manual. Set the carb using the tach per the manual's instructions.

For large Stihls you set the idle speed using the L screw, then set the free rev rpm using the H screw, then adjust the idle speed again. It's pretty easy. There are youtube videos showing it. Huskies may be different in procedure but should be similar.

Using the tach means you don't have to listen for four stroking in the cut. That's the other way to do it- cut with the saw and listen for the change in engine tone when you lift up. It should clean up under load and four stroke when you lift.

 

[newbury]

Re: Where痴 the best place or way to increase performance with a chainsaw.

I think someone posted this link before:Saw Carb Tuning
It's got 2 sound files you can listen to for tuning.
I tried to put them here but TBN refused.

 

[John_Mc]

Tuning by ear (just barely 4-stroking out of the cut at wide open throttle, then cleans up in the cut) is actually a more accurate way of dialing in the saw for best performance - IF you develop the ear for it. Some people also get confused by the rev limiter in today's ignition modules. Bumping up against the limits can make sounds which are mistaken for 4 stroking. When tuning by ear, it's best to approach from the rich side and gradually lean out the high speed mixture to avoid getting in the the rev limiter (which tends to kick in on the lean side).

Having said that, I do own a good tach and sometimes use it to double check my tuning by ear. It's important to get one which works at high enough RPMs (many are made more for lawn mower type engines, and max out well below a chainsaw's RPM range). It's also important to get one with a fast response time. I use a DTI TECH-TACH TT-20K. It handles up to 20,000 RPM with a 0.5 second update time.

 

[John_Mc]

Re: Where痴 the best place or way to increase performance with a chainsaw.

I think someone posted this link before:Saw Carb Tuning
It's got 2 sound files you can listen to for tuning.
I tried to put them here but TBN refused.

That was probably me that posted it. It's a great resource. The same site has a lot of other good tips which can be found at Madsen's Pro Chainsaw Maintenance & Repair. There is quite a bit of good info under their Chisel Chain Maintenance link.

 

[CincyFlyer]

A good nitromethane fuel with appropriate jetting will do the trick.

 

[sd455dan]

Yes it would

or as 4570Man said:

The 372 isn’t a good lab rat for mods- I might start with my smaller and cheaper saws. I’ve got a 353 Husqvarna

Getting 5 hp from those saws would be a real game changer.[/QUOTE]



a 353 Husky that does not see much use anymore...



Did some more reading and it looks like 353 is similar to the 340 which was what the winner of the competition actually was,

These models can all be modded like the winning saw (from the dyno video i posted earlier) ArboristSite:

(340, 345, 350, 351, 353, 346 NE and OE. Both the 340 and 345 will need the modified 350 bearing cup/cylinder base.)



The 5 hp+ saw was also built by the same builder that newbury mentioned (Brad Snelling)



from what I can find, saw had these mods- there may be more

New cylinder from a NE (new edition) 346 -
ported, -exhaust 106*, intake 80*, transfers intake side 120*, exhaust side 122* widened exhaust matching contour of original, intake widened, transfers on the exhaust side widened toward exhaust port

machined piston crown to make it a pop up, .040 raised crown, .280 squish band width

175 psi compression

squish of .014, cut down bearing cup /cylinder base to achieve that squish, also port matched and smoothed

357 carb and intake tract- Brad mentioned that he thought that alone was worth about 8% of the power gain

Muffler opened up under screen

stock ignition timing - Some have mentioned that advancing the ignition timing and /or an unlimited RPM coil might wring a little more out.



What is amazing to me is Brad built the powerhead in the evening after driving to buy the core and immediately shipped it :shocked:


members/builders on ArboristSite must have copied the power head mods by now,

Sure seems like there would be demand for 5+ hp saws the size and weight of the 340-353 huskys
Especially since at least 1 great build has been worked out.

Guessing because the the clam shell Huskies are considered consumer grade (plastic) saws- and the cylinder/ piston he used is about $130 and about $65 for the intake carb parts + porting and having the piston modified along with bearing holder/ cylinder base cutting/mods plus reassembly

It gets a bit costly for what is still a plastic cased saw, and there is even a debate on whether that is a big deal, It sure makes doing squish changes easier.

on another site someone had asked if Brad builds saws by request and from his answer it would appear he does not.

My hat is off to him-
Impressive saw building- and it was nice of him to share build specs and parts list even if not building saws for others.

It would be nice to know how well that particular saw has held up over the last couple years.

Anyway, the Husky 353 looks like a candidate for modding.





ps. a correction from earlier post - the saw that was a dog in the dyno test making only 2 hp was the Kafar kit saw. stock 350 husky ran better



newbury I think you scored on some great modded saws:thumbsup:

 

[4570Man]

Yes it would

or as 4570Man said:

The 372 isn’t a good lab rat for mods- I might start with my smaller and cheaper saws. I’ve got a 353 Husqvarna

Getting 5 hp from those saws would be a real game changer.

a 353 Husky that does not see much use anymore...



Did some more reading and it looks like 353 is similar to the 340 which was what the winner of the competition actually was,

These models can all be modded like the winning saw (from the dyno video i posted earlier) ArboristSite:

(340, 345, 350, 351, 353, 346 NE and OE. Both the 340 and 345 will need the modified 350 bearing cup/cylinder base.)



The 5 hp+ saw was also built by the same builder that newbury mentioned (Brad Snelling)



from what I can find, saw had these mods- there may be more

New cylinder from a NE (new edition) 346 -
ported, -exhaust 106*, intake 80*, transfers intake side 120*, exhaust side 122* widened exhaust matching contour of original, intake widened, transfers on the exhaust side widened toward exhaust port

machined piston crown to make it a pop up, .040 raised crown, .280 squish band width

175 psi compression

squish of .014, cut down bearing cup /cylinder base to achieve that squish, also port matched and smoothed

357 carb and intake tract- Brad mentioned that he thought that alone was worth about 8% of the power gain

Muffler opened up under screen

stock ignition timing - Some have mentioned that advancing the ignition timing and /or an unlimited RPM coil might wring a little more out.



What is amazing to me is Brad built the powerhead in the evening after driving to buy the core and immediately shipped it :shocked:


members/builders on ArboristSite must have copied the power head mods by now,

Sure seems like there would be demand for 5+ hp saws the size and weight of the 340-353 huskys
Especially since at least 1 great build has been worked out.

Guessing because the the clam shell Huskies are considered consumer grade (plastic) saws- and the cylinder/ piston he used is about $130 and about $65 for the intake carb parts + porting and having the piston modified along with bearing holder/ cylinder base cutting/mods plus reassembly

It gets a bit costly for what is still a plastic cased saw, and there is even a debate on whether that is a big deal, It sure makes doing squish changes easier.

on another site someone had asked if Brad builds saws by request and from his answer it would appear he does not.

My hat is off to him-
Impressive saw building- and it was nice of him to share build specs and parts list even if not building saws for others.

It would be nice to know how well that particular saw has held up over the last couple years.

Anyway, the Husky 353 looks like a candidate for modding.





ps. a correction from earlier post - the saw that was a dog in the dyno test making only 2 hp was the Kafar kit saw. stock 350 husky ran better



newbury I think you scored on some great modded saws:thumbsup:[/QUOTE]

That 353 Husqvarna has earned its keep even if it’s in retirement now. And it is a pretty good cutting saw. I’d take it over a Farm boss Stihl any day. I wouldn’t consider it a homeowner grade saw. Maybe a low end pro saw. I haven’t used the 540 Dolmar, but it’s supposed to be a pretty good saw. What would it cost to send the saw to someone to do that? I could probably figure it out but I’ve got a lot of projects.

 

[John_Mc]

The Husqvarna 353 might be a great place to start. They were a saw with pro-type construction without the pro level price. I own the twin sister, a Jonsered 2152. The only "Mod" I've done was to replace the catalytic muffler with a non-cat one (and adjust the carb afterward). It added a little more power, but what I was really after is that it helped the saw run much cooler.

My friend had a 353 which developed piston/cylinder problems (probably bad gas). He had a saw shop near by replace the c & P with 346XP parts and do some mild porting. That really made a difference on his saw.

Another good saw to start with is the Husky 359 (a 60cc saw). It's another one that had pro-type construction for less than pro price. They were solid saws to begin with, and provide a good base to start from without costing a pile of money if you want to try modding a saw.