Author Topic: 4 stroke chainsaws? (Read 2672 times)

Deadwood · « **on:** October 29, 2005, 02:10:16 am »

Does anyone know if there is any 4 stroke chainsaws on the market?

Despite having a career that is depends solely on the two stroke engine (Railroading and EMD Locomotives), over the past few years I have been deliberatly getting away from the two stroke engine. The powerband is the biggest reason and recently I made two purchases that were 4 stroke, while just a few years ago you could not buy anything but two strokes.

The latest was my new snowmobile. Obviously that has been dominated by 2 stroke engines. The other surprising one though was my weedwacker. That is so tiny, tiny but that is also a 4 stroke now. This just leaves my chainsaw in the 2 stroke category. I would upgrade that to a 4 stroke as well if there was a manufacturer that offered such a saw. So does anyone know...

If any major saw manufacturer plans on making a 4 stroke saw?
If there is any 4 stroke saws out there now?
If emissions regulations are going to force manufactuerers to make them?
If they are out there, if they are any good? Powew Band? Weight? Etc?

I am not trying to be funny here either. I have never heard any information about 4 stroke chainsaws.

Rockn H · « **Reply #1 on:** October 29, 2005, 02:41:35 am »

Now I'm curious. I don't think I was aware of any weedeaters being four stroke yet.

Of course 4-stroke out board boat motors are what everyone here is going to. They are so quiet and really fuel efficient compared to the 2-strokes. I would like to find out about chainsaws myself. Of course I didn't know about the weedeaters so I'm not much help.

iain · « **Reply #2 on:** October 29, 2005, 03:03:55 am »

Four stroke

i cant help thinking water cooled

and stick shift or auto

sorry im not much help here

iain

Deadwood · « **Reply #3 on:** October 29, 2005, 03:31:45 am »

Yeah guys no kidding. I have a Ryobie Weedwacker, something like 50 cc's. The killer part is that it is the best weedwacker I ever had. You want to talk about powerful. Man what a powerband. For it small size, it really gets after the brush and does not die out at all. The only problem I have found is with fuel storage. Because the float is so small on the weedwacker, twice I have had to clean a tiny droplet of water out of the carb. It's no big deal, but then again I am handy with such mechanics. I know fuel consumption with a weedwacker is not anything of concern, but a pint and a half of fuel allowed me to weedwack my whole lawn all summer. Of course there could be mnay variables such as lawn size and whatnot, but I will say this. It was very impressive when it came to fuel economy.

Now as for the 4 stroke snowmobile. It seems as if Yamaha, a sled maker that has rewally embraced the 4 stroke snowmobile market, is doing well this year. Sales are huge. The funny thing is, their 4 strokes are turning higher rpms then the two strokes. Their redlines are higher too. In the sled world, 5000 miles is about all you can get out of a motor before rebuild. The Yamie dealer told me to check the motor at 14,000 miles. The valves are supposed to be adjusted at 26,000 miles. By that point the rest of the sled will be wiped out. This longevity is why I bought the 4 stroke. I put on 3240 miles last year so mileage is huge to me. Add to that gas savings of 20 mpg vs 12 mpg and you can see why 4 stroke is looking good.

Anyway, all this makes me wonder if there is a 4 stroke saw out there? I know weight would be just as much of a concern with a saw as it would with a snowmobile. The latter machine is still struggling with weight as the 4 strokes are heavier than the two strokes. As I said though, it would be interesting to see if anyone is heading towards a 4 stroke saw, or better yet, producing one now.

Rockn H · « **Reply #4 on:** October 29, 2005, 03:39:46 am »

The 4-stroke jet skies and out boards really have the 2-strokes beat hands down. If that Ryobi has a 50cc engine that in a chain saw chassis should handle a 18" bar pretty easy shouldn't it? I just don't know if your german manufacturers will be very quick to go 4-stroke. Then again I saw where Briggs was offering bars and chain on their corp. web site.

sawguy21 · « **Reply #5 on:** October 29, 2005, 04:28:45 am »

There are no 4 stroke saws on the market yet but I would really like to try one. Shindaiwa has developed some prototypes with their C-4 hybrid technology, 4 strokes that use mixed fuel, but will not introduce them until forced to by emission regs. A Shindaiwa rep told me he had run an 80cc version in Japan and that he could not stall it. The torque and throttle response were amazing. It was very smooth too.
There are a number of such trimmers out there. Honda has a true four stroke with a dry sump and others like Husky use their engine. Stihl has 4-mix which, like Shindaiwa's C-4, is a hybrid.
Briggs has bars and chains because they have recently taken over distribution of Dolmar in North America.

Ironwood · « **Reply #6 on:** October 29, 2005, 07:30:10 am »

Good for you, I do hate the fumes from all 2 cycles. BREATHE EASY BRO.

REID

Kirk_Allen · « **Reply #7 on:** October 29, 2005, 08:26:37 am »

I have a Stihl 4 stroke weed wacker but it too requires fuel/oil mix. It runs 100 RPM faster than the 2 stroke version and seems to have quite a bit more power.

JimBuis · « **Reply #8 on:** October 29, 2005, 08:45:27 am »

You can read about Dolmar's plan for a 4 stroke chainsaw at this link:
small links are the best links

The article is a little on the technical side. It sounds like the production of a 4 stroke chainsaw is due anytime now.

twostroke_blood · « **Reply #9 on:** October 29, 2005, 10:01:42 am »

AS for me. I'll stick with my TWO STROKE's billowing clouds of 20:1 mix.

floyd · « **Reply #10 on:** October 29, 2005, 12:08:15 pm »

iaian, think vw...aircooled

Sawyerfortyish · « **Reply #11 on:** October 29, 2005, 06:01:20 pm »

My 066 runs at 15800rpms I don't think they can get a 4 stroke to run that fast if they can even make one comparable in weight. I think theres a big saftey issue if a saw won't run fast enough to cut off a tree.If they do come out with something they'll have to prove it to me. Nothing like 2 stroke smoke to keep the bugs away.

Dan_Shade · « **Reply #12 on:** October 29, 2005, 06:27:53 pm »

chainspeed is the end result you are after....

if a 4 stroke is light enough, you can put a gear box on it, but that's more moving parts.

my brother has a 4 stroke dirt bike, it's pretty quick, but they may do funky things with it's gear box too...

getting 4 strokes to rev high takes a good balance and a short stroke, if the inertia is low enough, you can probably spin one to 13000rpm.

You have a modded saw to make it turn 15k? I think the 066 was rated at either 12.5k or 13k from the factory.

Rocky_J · « **Reply #13 on:** October 29, 2005, 06:59:11 pm »

Chain speed can also be modified by using different size drive sprockets. Just because my 2 stroke 372XP works well with an 8 pin sprocket, doesn't mean that I'm required to use that same 8 pin sprocket on a 4 stroke saw turning 2500 rpm's less. As long as the motor has the torque, you can bump up the sprocket size to achieve the desired chain speed.

Dan_Shade · « **Reply #14 on:** October 29, 2005, 07:30:20 pm »

actually, you'll need more torque for a larger sprocket to keep the same chainspeed in a cut.

I didn't mention the sprocket, because I have no idea of the RPM difference. if it's half the RPM, then that would require a much larger sprocket, and then you may have problems keeping the chain in the rail. if you use a regular bar designed for a smaller sprocket.

I guess I'm saying that we're gonna have to wait and see what they do. I used a 4 stroke weedeater, and it basically sucks, worse "tool" I've ever attempted to use, but I'm sure it was a very low end model too....

Sawyerfortyish · « **Reply #15 on:** October 29, 2005, 08:48:11 pm »

My 066 has been played with. I think factory max rpm is 13500. I have a 044 that runs faster than that

But you guys are hitting on exactly what i'm trying to get at. Someone is gonna have to play around with 4 stroke moters sprockets and maybe wider bars to fit larger sprockets or gear boxes and make it all come togeather at a weight you can carry around in the woods and then make it relaiable. This ain't gonna happen overnight. It's gonna take years of trial and error.
What I would really like to know is it going to make that much of a differance in the amount of emmisions on such small engines Verses just leaving things alone. I think they could make more differance if they did something about all the jet fuel going through the planes in the sky!!

Rocky_J · « **Reply #16 on:** October 29, 2005, 08:55:01 pm »

SF'ish,
Don't go off trying to be logical. Don't you know by now that when it comes to government, logic does not apply. The only thing that matters is that you follow the rules. If you attempt to apply logic, you will confuse and/or irritate the government employee trying to make you compliant. And that never leads to anything good.

The rules are that small gasoline engines must reduce emissions by X percent within the given timetable. That's the rules, don't go trying to re-negotiate using logic.

Sawyerfortyish · « **Reply #17 on:** October 29, 2005, 09:06:43 pm »

Ohh well just forget I said that I wouldn't want any gov guys in black suits showing up at my door

Frickman · « **Reply #18 on:** October 30, 2005, 02:38:06 pm »

Stihl's 4-stroke weed trimmer is extremely powerful, with incredible torque. I don't own one, but have friends in the lawn care business that have let me try one. They said that they are more expensive than a 2-stroke, but pay for themselves over time. I too haven't seen a 4-stroke saw, but I'm sure many companies are working on one.

Deadwood · « **Reply #19 on:** October 31, 2005, 07:23:19 pm »

I don't think engine RPM is going to be a problem. Currently my 4 stroke snowmobile engine turns 600 rpm faster than my friends Ski Doo 2 stroke engine...and mine has a few more horsepower to boot (120 vs 107). The redline on my machine is also higher at 10,000 RPM while his is at 9400. How they got these small engines to crank so high is beyond me, but since the valves are due to be adjusted at 26,000 miles and a 2 stroke engine is junk at 8,000 miles, I think longevity is where the 4 stroke versus the 2 stroke chainsaw will really pay us dividends.

As for the emissions, we do get a side benefit to them. A lot less fuel consumption. My old snowmobile got 12 miles to the gallon, this sled will get 20. At 3.15 a gallon like it was a few weeks ago, it doesn't matter if the fuel tank capacity is measured in gallons or pints!

Personally I can't wait for a 4 stroke chainsaw to debute. I be at the shop door waiting for it to open on the first day of sales.

Ianab · « **Reply #20 on:** October 31, 2005, 08:30:23 pm »

Quote

I don't think engine RPM is going to be a problem.

I agree.

My Toyota Corolla revs to 8,000 rpm (factory standard) - same as my Stihl 090.

Be some interesting challanges about weight and cost ( more moving parts isn't going to make them cheaper ). But there is nothing inherently impossible about making a 4 stroke chainsaw so I'm guessing they will appear in due course.

Ian

rahtreelimbs · « **Reply #21 on:** November 02, 2005, 07:10:21 pm »

I like new technology!

I would like to see what can be built in a 4 stroke chainsaw.

I am not giving up my 2 stroke saws anytime soon!

Just want to see want can be done!

Deadwood · « **Reply #22 on:** November 03, 2005, 06:50:23 am »

There will be challenges ahead for sure. One thing I failed to mention was how on my four stroke sled the motor is 973 cc's in order for it to compete with other 2 stroke sleds in the 600 cc class range.

I was reminded of this yesterday when a friend dropped by to look at my new sled. When he remarked how foolish it was for Yamaha not to put on a recoil I was reminded of this cc diference. Yamaha did not make a mistake, there is just no way the average person can pull start a 973 cc 4 stroke motor when it is 20 below.

Now all along I have compared 2 stroke sleds to 4 stroke sleds because this is an area that has always been ruled by 2 stroke powed. No doubt a 120 hp snowmobile is going to be different than a chainsaw. Still I see weight as the biggest issue to chainsaws. Like you I am interested to see what the engineers come up with. Heck maybe they will surprise us all and come out with a nuclear powered chainsaw?!!!

Dan_Shade · « **Reply #23 on:** November 03, 2005, 12:03:30 pm »

if we had a saw that "never"ran out of fuel, how would we know when to touch up the chain!

IndyIan · « **Reply #24 on:** November 03, 2005, 04:37:32 pm »

Well, I'm not sure 4 stroke saws are too far off... I don't really know if thats a good thing as they would be alot more complex/$$$ but they should run with less pollution.

One thing going for 4 strokes is that 2 stroke chainsaws don't have room for a proper tuned exhaust so they are at a big disadvantage compared to sleds or dirtbikes. So now the potential output of 70cc 2stroke or 4 stroke saw is closer compared to a 2stroke or 4stoke 250cc dirtbike.

I have read than evinrude has 2 stroke boat motors that get better mileage than 4 strokes so maybe the 2 stroke can overcome that advantage too.

Ian

Deadwood · « **Reply #25 on:** November 04, 2005, 02:35:32 am »

Again, I have to refer back to sleds because this is what I know best, and has the greatest 2 stroke versus 4 stroke battle that I know of. I think you are right though about fuel economy. Two stroke snowmobiles are getting about the same miles per gallon as 4 strokes. I think mine gets about one or two miles more per mile than my friends equivilent 2 stroke. I think the emission manadates levels out the playing field. If you are required to reach a certain emissions number, it's just common sense that burning the same amount of fuel will get you in the same ball park.

Ianab · « **Reply #26 on:** November 04, 2005, 05:57:30 pm »

Quote

If you are required to reach a certain emissions number, it's just common sense that burning the same amount of fuel will get you in the same ball park.

Not completely true...
Part of the emission standards is WHAT is being emmitted.
The 4 strokes will normally burn fuel cleaner, where a 2 stroke has a tendancy to spit out a bit of unburnt fuel / oil mix. The unburnt hydrocarbons contribute more to smog than the Co2 / H2o of fully burnt fuel. Yes the amount of fuel used is the same, but that 2 stroke 'smoke' is a greater pollutant.

Ian

Rocky_J · « **Reply #27 on:** November 04, 2005, 06:47:06 pm »

I've read that one 747 jet plane will burn more fuel in one cross-country trip than all the chainsaws in the United States will burn in one year.

Emissions requirements are a joke. They are a means to an end devised by wacko greenies to deprive the rest of us from the modern marvels of our time.

pallis · « **Reply #28 on:** November 05, 2005, 10:06:37 am »

I wholeheartedly agree with Rocky-J. Yes, 2 cycle chainsaws put out more pollutants and hydrocarbons than the V6 in my S10, but in real terms, the actual effect on our environment, it's infinitesimally insignificant. The exception might be something like peak use in cities during prolonged periods without wind. If you find yourselves in that situation, grab your 4 cycles, and pray for a breeze.

blueox · « **Reply #29 on:** November 05, 2005, 10:43:27 am »

I don't know a thing about Chainsaws ...but what I do know is that I LOVE to snowmobile. A couple years ago my husband surprised me with a beautiful BLUE (saphire blue) V-1000 Bombardier Grand Touring and she is a 4-stroke!! I love it!

I grew up on the front of my Dads snowmobiles...the carbrator right in my face ( no wonder I could fall asleep so easily on my rides with him....I was drugged!!) My Gem (snowmobile) is smooth...QUIET and no fumes!!! This is my winter Limo! (When I called my Mother-in-law to tell her that I got a new SAPHIRE for my birthday, she thaught for sure I got a new ring....I'd rather have the sled over a ring anyday!!)

My husband has a 700 Bombardier 2-stroke and he gets 1/2 the gas mileage that I get!!! But one problem we have encountered with mine is that we need to change the battery every year, we were told that this is a common problem with Arctic Cat 4-strokes as well!

Almost time to hit the trails. There is nothing better than working all day...getting bundled up at dark...and riding to the local pub for burgers and fries!!

Laurel

Deadwood · « **Reply #30 on:** November 05, 2005, 12:26:32 pm »

Yep, I know what you mean. In fact if you would like to join us, there is quite the snowmobile conversation going on in the Other Outdoor Interest's section of this website.

Furby · « **Reply #31 on:** November 05, 2005, 05:09:44 pm »

Here's a thought........
The 4 strokes have a bunch more torque, but less speed right.
Would a more agressive chain be better suited to a 4 stroke to help keep the cutting speeds balanced?
I mean, if you redesign a saw so that it is a 4 stroke, why wouldn't you redesign a chain to match the saw?

ElectricAl · « **Reply #32 on:** November 05, 2005, 06:03:56 pm »

I talked to a Stihl road rep at a small show today. I asked about Stihl's progress on a 4 stroke Chain saw.

His answer was, "Stihl will not develope a 4 stroke as long as they can meet EPA standards by using Catalytic Converters on 2 stroke saws"

james · « **Reply #33 on:** November 05, 2005, 09:51:16 pm »

any body for a wankel rotary i hav a friend who built a mazda rx-7 that would turn 20,000+

james

Deadwood · « **Reply #34 on:** November 06, 2005, 11:30:21 am »

You make a good point Furby. The point of a chainsaw is to make a cut in wood that is as fast as possable from point A to Point B. The simplest way to do that is to have high chain speeds, but it is possable to increase the amount of wood taken per tooth so that wood removed would be higher to match the available torque of the 4 stroke engine.

leweee · « **Reply #35 on:** November 06, 2005, 12:13:34 pm »

They all ready make 4 stroke saws with special chain.

Check it out http://www.forestryforum.com/board/index.php?topic=9639.0

They just ain't practical for everyone

New Link....http://www.killsometime.com/video/video.asp?ID=297

Ianab · « **Reply #36 on:** November 06, 2005, 02:30:49 pm »

Quote

any body for a wankel rotary

Been done already by Dolmar.
Never caught on, but maybe with the better technology that Mazda have developed with the rotary engines now it could work..

Cheers

Ian

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Author Topic: 4 stroke chainsaws? (Read 2672 times)

Kirk_Allen