Post by: ej on February 02, 2015, 08:26:43 pm
Post by: 660magnum on February 02, 2015, 08:31:20 pm
Larger chainsaws, for race saw applications, sometimes have the head machined off and a new head made. They are sometimes bored and or sleeved.
Post by: Cut4fun . on February 02, 2015, 08:33:31 pm
Post by: Cut4fun . on February 02, 2015, 08:34:07 pm
About $300 to do.
Post by: Cut4fun . on February 02, 2015, 08:34:48 pm
I had one that wasnt stroked with a 038 mag piston 76cc. stroked one was quicker
Post by: ej on February 02, 2015, 08:39:02 pm
Post by: ej on February 02, 2015, 08:40:40 pm
Post by: ej on February 02, 2015, 08:43:43 pm
Post by: Cut4fun . on February 02, 2015, 08:57:42 pm
kevin I still have a chance to get bigger 272 pistons what if it was 55mm bore whats that figure out to
Bingo 80811.49589cc I'd call it 81cc
Post by: Cut4fun . on February 02, 2015, 09:00:07 pm
5 cubic inches = 81.93532
Post by: EHP on February 02, 2015, 09:24:26 pm
Post by: ej on February 02, 2015, 10:04:56 pm
Post by: Cut4fun . on February 03, 2015, 01:03:11 pm
EJ , bore times bore times .7854 times stroke . Those 272's your talking about were not 72cc or 81cc , they were 96cc
Please show me how a 55mm bore x 34mm stroke is 96cc like you say above?? 55mm x 34mm is closer to 81cc in my we brain work.
Using a 54mm on a stock stroke 272 34mm = almost 78cc 77899.61
Post by: Cut4fun . on February 03, 2015, 01:06:48 pm
Post by: EHP on February 03, 2015, 06:27:46 pm
Post by: ej on February 03, 2015, 06:48:20 pm
Post by: Cut4fun . on February 03, 2015, 07:30:55 pm
those 96 cc 272's didnot go west , they went south and were not 55 or 54 mm by 34 stroke , 56 mm bore by 39 mm stroke , It does fit but not much left in the crankcase to spin the crank over . I never built 1 but I might have seen a couple :o. I did build a 52 mm bore by 38 mm stroke to run in the 5 cu class thou , Use the longer rod off the 372 on the stroked 272 crank , 372 rod is 3 mm longer than the 272 rod so at 38 mm stroke it stops the crank from touching the bottom of the piston . 39 mm is a bit tight in the case but no more than guys putting 47 mm stroke in 3120's
Thanks for explaining Ed.
I was hoping you were talking different saws then we were.
I've heard of a 272 crank etc down in a ( I think husky 50) for a 3ci saw before. Ran against it and beat it. So didnt bother me.
Now the 46mm 325 or 55 top on the 50 490 590 5000 crankcases you could see and hear the difference in the cuts. Knew of a couple of those out there.
Post by: mcbob on February 04, 2015, 11:34:24 am
yah I have had a lot over bore by u.s chrome and millieum and max power. I have bored the 166 sachs and put a 3120 big bore 62mm in it and it was a two piece herb gingras got it now I got some 272 pistons 54mm getting made too at the same time as my the big 70mm 090 pistons getting done. m.v used too put 288 cylinders on the 272 bottom and ran real strong I thought it would be easier to just bore the 272 cylinder instead and make it a 5 cube saw
Whats happening with the 70mm Stihl 090 cylinder you getting some made or plan on boring the old cylinder ?
Post by: EHP on February 04, 2015, 06:38:32 pm
Post by: ej on February 04, 2015, 08:53:09 pm
Post by: mcbob on February 07, 2015, 03:39:27 pm
Post by: chainsman1 on March 19, 2015, 09:44:09 pm
yah I have had a lot over bore by u.s chrome and millieum and max power. I have bored the 166 sachs and put a 3120 big bore 62mm in it and it was a two piece herb gingras got it now I got some 272 pistons 54mm getting made too at the same time as my the big 70mm 090 pistons getting done. m.v used too put 288 cylinders on the 272 bottom and ran real strong I thought it would be easier to just bore the 272 cylinder instead and make it a 5 cube saw
When putting a 288 cylinder on a 272, what piston has to be used?
Post by: scott kunz on March 20, 2015, 03:34:06 am
Post by: Eccentric on March 20, 2015, 04:48:17 am
does any one here stroke cranks? or where do you send them? does 55x41 get me in 6 cube? is there a longer rod that fits a 385/390? thanks, scottThis is getting interesting.
55mm x 41mm gives 97.409cc by my maths Scott. That's just shy of 6ci (which is a hair over 98cc IIRC).
Post by: mdavlee . on March 20, 2015, 09:35:13 am
Post by: aclarke on March 20, 2015, 09:59:39 am
Post by: Cut4fun . on March 20, 2015, 12:47:49 pm
Post by: Cut4fun . on March 20, 2015, 08:10:00 pm
6 cubic inches = 98.322cc
Post by: scott kunz on March 21, 2015, 05:30:28 am
I came up with a different way to stroke a crank, if it works i'll post some pics.
Post by: mdavlee . on March 21, 2015, 09:35:34 am
Post by: Cut4fun . on March 21, 2015, 09:13:03 pm
I have had a lot of guys asking about strokers for stihl's
first anything can be done if you want to spend enough money but most stihl's are a 2 piece crank . This means the pin and one side of the crank are made from one piece of steel. The otherside is normal so if you want to stroke a stihl you would need to build the side that has the pin in it so you can stroke it. Like i said it can be done but cost alot of money . The 460/ 046 stihl is a 3 piece crank that can be stroked easy .The 084 and 088 are 2 piece cranks
on strokers you are looking to make more torque which they do.
The muffler class saws are the most type of saw that will gain the most, because torque is what they need.
The 3120 is the most stroked saw outthere, i have stroked other saws but mostly 3120's
On stihl's like the 046 when you stroke it by 4mm ,, so this means you more the pin 2 mm to get a 4mm stroke , you have to change the rod as well because it is to short now and the piston will hit the crank at bottom deadcentre and you will not beable to turn the engine over.
Plus the longer rod helps give you more torque because as the motor turns over the rod doesnot have to be at such a sharp angle with a longer rod , the sharper angle takes more power to turn over and tears the face off the piston on the intake side on racing motors with big ports
But to be honest most guys i could hand them a saw and they still would not be able to make it work as good .Now i donot mean in any way that my head is as big as a football or that i an god .What i mean is most guys are not carefull enough and what they might think is nothing is life or death to me
now someone like Dozer Dan i believe would be able to copy one of mine because he knows that you have to take your time and do it once and right. I am sure there are others
The carb is like a work of art , one wrong stroke and you are buying a new one to start over, have i scraped a few you bet
no one showed me how to do it so i just figured it out myself now it is not as simple as drilling the jets out because for the top of the line carbs you need to make a whole new high speed side in the carb , this means the jet ,nozzle ,needle and fuel route
on the low side you just need the drill the low side and fuel route.
I think i have 1 carb left that we call a doule pumper. it is a HS carb that has been moddified so much that we take a second carb and machine it so it will be the pump side and it bolts on top of the other carb , we bore the first carb so much that we go threw its part that pumps, now i will tell you guys this ,when you bore your carbs donot touch the low speed hole side , this is a no no, when boring a HS carb you have to offset the carb to make it bigger
my small HS carbs have a bore of .988' , now the 3120 carb stock is 1.062 ' and the small carb will pump the same amount of fuel as the bigger carb
the 3120 crank is alot longer than a 088 crank
3120 crankcase is lot wider than the 088
the clutch is different on how it goes on plus why would you do it for only 1 mm longer stroke
now are sure that they were not talking about the 084 rod
yes we put the 084 rod on the stroked 3120 cranks
you cannot use the 088 rod the pin is bigger
next time you are in the shop take a 3120 crank and put it next to a 088 crank and you will see no way
Somebody asked a question or two regarding how to "stroke" a crankshaft; There a couple of ways, but none are cheap or easy.
Way back when, when rod caps came off, even on two-strokes, the rod journal could be built up with weld, and reground to diameter at the new swing point. Since the heat-treat was no longer any good, they wouldn't last. Later, some electrodeposition and metal-spraying companies could put a hard-surfaceing deposit on the rod journal that partly alleviated this trouble.
later cranks came apart in 3 or more pieces, and those were easy: press apart, rebore the crankpin holes to the new location, at a larger diameter, install bushings to reduce back to the original crankpin size, and reassemble.
EHP talks about 2 piece Stihl cranks: these can be dealt with somewhat like a one-piece set-up.
BUT
You still must deal with rod length problems and/or/ piston head/deck height situation. I have built some Honda 4-stroke strokers for modest increases in stroke the steel rod can be shortened by heating and hydraulically comprssing the rod, allowing the use of factory pistons.
Longer strokes call for a custom machined rod, or if you're really lucky, maybe something else will work: Honda 185 four stroke engine can be stroked abouit 2 mm with a CR125 rod, but will require bushings in piston.
Another option can be a custom piston with a short wrist-pin to deck height. keep in mind that you've radically changed the stroke-rod-length ration, and will also effect port timing radically.
My uncle raced snowmobiles, I helped load and unload, other gopher work, and did some wrenching. We worked a lot with an engineer at the snomobile company that sponsored us There were many many engines that responded very poorly to stroking... actuallly lost power.
My opinion, unless you have time and money to burn, it probably isn't worth it for a chain saw. 4-strokes can often use stroking to extend a narrow powerband on an over-cammed engine...I've assembled several Honda XL-350's to around 460cc, that would make a Yamaha TT500 with cam, carb and pipe look ill.
i feel that stroking is worth every cent
if you go to a contest and there are 5 strokers there and they pay 5 places as long as they donot make any mistakes you know the saying
to bad so sad no money for you because they got it because they whip your ass
i feel the only way to stroke a crank is to press ot apart and then file the rod pin hole in with the same rockwell hardness as the crank , bore your new hole for your pin and all this without heating the crank
I have never seen a stroked work saw , this doesnot mean that they are not out there it just means that i have never seen one.
now you would have to have a head on it right ?
or do you but a spacer under the jug to raise it so you donot hit the top with the piston but if you do this you are going to increace your port timing numbers alot on the ext. port an tranfers ports but like i said i have never seen a work saw that was stroked but i am sure they are out there
no i have not seen that site before but i have bored the 371 when it came out and stroked them to get them up to the 81 cc limit but that is boring not stroking and for what i have seen a 372 and the 046 with muffler mods would be my pick over the 385 . i wish some day someone would show me a 385 that would cut , just donot like them
i have ran 7 or 8 of them but have never worked on any of them
first off if i am going to use a saw for falling or cutting on the landing it better cut or she will get the treatment , i have no time for something that i feel doesnot work so under the D8 cat and us it for fill
the ones that i have ran have no torque at all for staying power in the cut ,and they had a 7 tooth gear on them .
the factory must feel the same because they put them out with a 7 tooth on them and a saw with that many cc should care a 8 tooth with no problems on a 20 inch bar
i know the guy that did the testing on them before they came out on the market and he does not like them either
he is like me he runs a 372 instead but likes the 7900 dolmar to.
i guess if i am going to care that much weight it better cut and i donot feel they do maybe if a modified one then i could be happy
the 372 works so well with a little help that i like them ,but if i am cutting softwood i like the 046 /460 , man i can get them to turn up and they cut fast and they are great on hardwood to be i like the springs mounts on the 372, easier on the white finger
but if i am going to care a bigger saw it is going to be a 066/660
you can make them haul ass pretty easy
Post by: scott kunz on March 22, 2015, 03:29:07 am
Post by: Playinwood on March 22, 2015, 09:34:47 pm
Post by: 3000 FPS on March 23, 2015, 12:07:56 am
Post by: Cut4fun . on March 23, 2015, 12:53:30 pm
2004 ? ;D
2004 ? ???
Post by: Cut4fun . on July 01, 2015, 01:59:56 pm
thanks for the info guys
I came up with a different way to stroke a crank, if it works i'll post some pics.
Who would have thought my little sentence referring to this would get someone so bent out of shape. :o ::)
So is this the crank from this thinking?
Post by: EHP on July 01, 2015, 10:48:40 pm
Post by: Cut4fun . on July 02, 2015, 10:07:47 am
I had a MVP full circle I bought from Simon.
(http://i59.photobucket.com/albums/g289/doemaster789/5000/CopyofCavemanmufflermods004.jpg)
(http://i59.photobucket.com/albums/g289/doemaster789/5000/CopyofCavemanmufflermods005.jpg)
Post by: EHP on July 02, 2015, 10:59:07 am
Post by: scott kunz on July 04, 2015, 04:03:10 am
thanks for the info guys
I came up with a different way to stroke a crank, if it works i'll post some pics.
Who would have thought my little sentence referring to this would get someone so bent out of shape. :o ::)
So is this the crank from this thinking?
what a hoot that was, most fun I've had in a long time.
poor randy, he took the bait big time.
that crank was for a 2165 4 cube, external transfers, big carb, on muffler. it came apart at over 20,000, not much left.
Post by: Cut4fun . on July 05, 2015, 12:19:15 pm
thanks for the info guys
I came up with a different way to stroke a crank, if it works i'll post some pics.
Who would have thought my little sentence referring to this would get someone so bent out of shape. :o ::)
So is this the crank from this thinking?
what a hoot that was, most fun I've had in a long time.
poor randy, he took the bait big time.
that crank was for a 2165 4 cube, external transfers, big carb, on muffler. it came apart at over 20,000, not much left.
Saying catching up to ole Scott I didnt see it as baiting. ( I didnt even think of it like that till stihlbro brought it up).
I was just glad to see someone else thought of the idea. Who ever that other guy was that brought it to randys attention to try a stroked crank is on top of the thinking like you are. 8)
Now all the other accusations that were made was just total imaginary made up in the mind BS :o.
Found the original post. (just catching up to what ole Scott has been thinking all along.) How someone can take that and say we were accusing them of stealing ideas is beyond my little mind. ::)
Post by: EHP on July 05, 2015, 05:17:18 pm
Post by: HolmenTree on July 05, 2015, 09:46:54 pm
Post by: scott kunz on August 13, 2015, 02:58:45 am
Post by: mdavlee . on August 13, 2015, 04:30:42 am
Post by: aclarke on August 13, 2015, 12:01:34 pm
Post by: Cut4fun . on August 13, 2015, 12:44:26 pm
Post by: mdavlee . on August 13, 2015, 03:32:20 pm
Post by: 3000 FPS on August 13, 2015, 10:34:57 pm
Post by: scott kunz on August 16, 2015, 04:10:38 am
Post by: scott kunz on August 16, 2015, 04:12:28 am
Post by: scott kunz on August 16, 2015, 04:54:54 am
rod and bearing from a Brocken 066 crank
crank pin from a 365 crank that was removed from the case with a hammer
using a 288 piston, did a little clearance work
Post by: scott kunz on August 16, 2015, 06:09:39 am
ex 176
in 161
cut the base .040, no gasket
ex 168
in 170
bd 22
tr 124
I think i'm going to raise the in floor with epoxy, put the thing together and see how it runs, check comp and go from there
Post by: Cut4fun . on August 16, 2015, 09:54:53 am
Thanks for sharing pics etc.
Post by: adam32 on August 16, 2015, 01:08:09 pm
Post by: mdavlee . on August 16, 2015, 06:13:22 pm
Post by: 3000 FPS on August 16, 2015, 11:11:53 pm
Post by: scott kunz on August 17, 2015, 12:56:07 am
Post by: aclarke on August 17, 2015, 10:09:18 am
Post by: adam32 on August 17, 2015, 10:25:10 am
true the crank, yes. balance the crank, no need too. it's a experiment, race saw. otherwise it would be done on the flywheel.
Hold on tight and make sure EVERY nut and bolt has Loc-Tite ;)
Post by: EvilRoySlade on December 14, 2015, 11:02:45 pm
Post by: Cut4fun . on December 15, 2015, 03:34:41 pm
So...does it run?
I'm not sure but maybe it was wild thingy ??? http://chainsawrepair.createaforum.com/ported-work-race/wild-thingy/
Post by: Chris-PA on December 17, 2015, 04:27:39 pm
Post by: Cut4fun . on March 04, 2016, 09:32:29 am
(http://i59.photobucket.com/albums/g289/doemaster789/5000/CopyofCavemanmufflermods004.jpg)
Post by: Cut4fun . on March 04, 2016, 10:13:51 am
Post by: lumberjackau on March 20, 2016, 06:29:48 am
@bertrand what was the filler that Marcel MVP used on this 5000 full circle crank? Anybody remember?Just had a look at this pic mate, is there some dab of welds on there to hold the filler in?
(http://i59.photobucket.com/albums/g289/doemaster789/5000/CopyofCavemanmufflermods004.jpg)
Post by: Cut4fun on March 20, 2016, 08:00:43 pm
Post by: lumberjackau on March 21, 2016, 06:01:07 am
Cheers
Will
Post by: adam32 on March 21, 2016, 10:01:55 am
Post by: aclarke on March 21, 2016, 03:47:28 pm
I'd use Devcon (Titanium or Aluminum) its a lot more tolerant of Alcohol and nitro thank JB weld.
Post by: Cut4fun . on March 21, 2016, 04:49:37 pm
Post by: adam32 on March 21, 2016, 09:52:34 pm
Post by: lumberjackau on March 22, 2016, 08:03:05 pm
Post by: aclarke on March 22, 2016, 08:56:58 pm
Post by: SquareFile on October 19, 2019, 11:07:57 am
Post by: Cut4fun . on October 19, 2019, 11:45:43 am
