High Quality Chainsaw Bars Husqvarna Toys

Woods ported my 660.

Absolution

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I believe the flywheel puller I bought which is what I was going to use to hold the timing wheel on is lost in mail. So, Still no numbers however I took the transfers down to base of cylinder. Once that tool comes in I'll be changing timing and adding finger ports.
 

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MustangMike

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I get why you did that, and let us know how it works (may be good on a Big Bore), but that mod also increases case volume (the opposite of crank stuffers).
 

Absolution

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I get why you did that, and let us know how it works (may be good on a Big Bore), but that mod also increases case volume (the opposite of crank stuffers).


Think you could go more in Depth with this? This is my second time with two strokes and I'm trying to go a little extreme. I'm used to Chevy and Olds porting on 4 strokes. Heck I even ported my 5.9 Cummins on exhaust side. But Two strokes are a different animal.

Edit: I understand case volume but my theroy is it would both flow better plus the higher compression would pull more vaccum on crank case. Therefor I could increase the case capacity. But know my logic is probably flawed.
 
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MustangMike

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Hey, if it worked, it worked. More case volume may be needed with a Big Bore.

As a general rule, a smaller case volume provides higher RPMs, but sometimes at the expense of torque.

But, each saw is different!
 
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Absolution

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Hey, if it worked, it worked. More case volume may be needed with a Big Bore.

As a general rule, a smaller case volume provides higher RPMs, but sometimes at the expanse of torque.

But, each saw is different!

Not running a big bore. But that general rule makes sense and in the future I'll make note.
 

drf256

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Not sure if you are chamfering your ports, I would if you aren’t. Use a diamond ball, I find it the easiest.

I’d forget the fingers for multiple reasons:

Those AM jugs have thin plating that chips easily

They dont really add that much to a work saw

Not sure how you will add them if you already widened the exhaust or you plan to lose the bottom ring and repin the top ring on your piston. The ring gap cannot ride over any opening in the plating. Unless you have room to safely rotate the piston 180* or you have another piston up your sleeve, I’m not sure how you will pull fingers off.
 

Absolution

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Not sure if you are chamfering your ports, I would if you aren’t. Use a diamond ball, I find it the easiest.

I’d forget the fingers for multiple reasons:

Those AM jugs have thin plating that chips easily

They dont really add that much to a work saw

Not sure how you will add them if you already widened the exhaust or you plan to lose the bottom ring and repin the top ring on your piston. The ring gap cannot ride over any opening in the plating. Unless you have room to safely rotate the piston 180* or you have another piston up your sleeve, I’m not sure how you will pull fingers off.

Ports are chamfered, the plating on this particular cylinder does seem to be thick and well done compared to a couple 090 cylinders I tried to clean up in past. I was also doing some reading though the porting threads where I had cut some much from transfers the fingers might make it worse even if I did squeeze it in there.
 

MG porting

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You're best bet is to leave that cylinder alone and sores out another one and yes those cylinders do have more plaiting on them but as much hoging out you did on the lower transfers I would recommend just leaving the one you got alone. You're learning baby steps next time.:beer-toast1:
 

Absolution

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You're best bet is to leave that cylinder alone and sores out another one and yes those cylinders do have more plaiting on them but as much hoging out you did on the lower transfers I would recommend just leaving the one you got alone. You're learning baby steps next time

Yeah, and next time I head to my shop in WV I need to find my right angle head. That's the only reason I butchered that cylinder was I tried reaching into transfers with a straight head.

Last night an idea popped into my head. I have a go kart body in WV that has a scored motor on it. I was thinking about getting another 660 motor and modding it to run it on the kart. Maybe do a pipe engine. That way I can have something to fool with.
 
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afleetcommand

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This was with a Oregon square grind which only had 5 cuts on it. I feel like the saw is has a lot more torque now than before.

Sounds like a nice running saw! The fact you actually use your saws gives you "enhanced" insight. Empirical data is by far the best way to measure the changes in your saw in your world. Keep learning & trying and try not to over analyse as that has stymied many... :)
 

Absolution

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Sounds like a nice running saw! The fact you actually use your saws gives you "enhanced" insight. Empirical data is by far the best way to measure the changes in your saw in your world. Keep learning & trying and try not to over analyse as that has stymied many... :)

I need to do another video since I advanced the timing, I shaved .015 off the key and I was talking to MG porting we believe my intake is low I'm getting of fuel/oil back in air box. It is probably where I swapped out to a pop up piston or It's always done it and I never payed attention.

Also I was reading an paper study on various porting methods. I spent the last 10 mins trying to find it with not luck. To summarize the paper the writer could only do air flow models do to his hardware limitation. So he was doing a direct injection model. With understanding that a carbureted engine could show different results.

Slick was fastest for air flow ( However he mentioned with a carburetor set up it would hender due to drop out)
Machine was a slower (But mentioned it would be best suited for fuel/air)
Dimples were interesting with various drawbacks. But not so clear cut.

At lower speeds dimples caused turbulence slowing down the velocity (Which was mentioned to prevent fuel drop out but he couldn't show it due to his hardware limitations)

The part which I'm more curious about is at higher speed. He said for airflow dimples where more of a hindrance. The whole theory of dimples is that it creates an air layer so fuel cant stick to walls or the air would move faster since it had a boundary layer. But that boundary was the problem decreasing port diameter choking how much air can move. (Since porting a 4 stroke isn't about blowing it up to the largest it can be it's about getting the port as straight as possible.)

This part interested me where I widened the transfers slowing down the velocity at lower speeds leaving more chance for drop out. I could put dimples in it getting the chance to reintroduce the drop out back into the mix then at higher speeds getting a tighter port to increase velocity in the transfers. However this is all theory to me. Unless I try to spend time and money to do a computer model. Not to mention the real world results would probably be in the gray area if it did anything or not without a dyno.

He finished off his study paper by talking about real world vs computer models. Computer models give us a really good idea about what is going on. However they are not always concrete evidence since the real world can have a variety of conditions. These tests were comparing ports of equal design all polished, all machined, all dimpled. Mentioning that maybe in a carbureted engine It could benefit from dimples in certain areas such as at the the end of a port or at low lying areas to give a point to throw setting fuel back up into air before entering cylinder.

If anyone knows this article and would take the time to send it to me that would be great. I think it was written by UNOH student as his graduating paper.
 

MustangMike

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Nice to know theory, but go with what works.

A little spitback is not uncommon. That is why the white air filters come with that foam insert (to reduce fouling on the filter). I am also careful to install my filters in the same direction each time, so the entire upper 3/4 does not get fouled. I doubt that it is happening at WOT. I would not be real concerned about it unless it is excessive.
 

Absolution

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Nice to know theory, but go with what works.

A little spitback is not uncommon. That is why the white air filters come with that foam insert (to reduce fouling on the filter). I am also careful to install my filters in the same direction each time, so the entire upper 3/4 does not get fouled. I doubt that it is happening at WOT. I would not be real concerned about it unless it is excessive.

I think I may do it. If I wreck a cylinder I wreck a cylinder. I've got my old mccullochs if I need too.
 

Absolution

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Okay, I took a break today and modified the bar so I could fit a 9 pin sprocket I've had laying around. This will also be the first video since the timing advance. I put a new Oregon square grind on it I'm trying to keep things the same.

I did one cut in the hard wood to reference my previous video and switched branch that had just started to rot, It is still pretty firm and I would put it in the same category as a tough pine. ( I'm sorry for smudges on camera)

EDIT: That first cut was slowed due to user error. I need to go back and do it again.


I can't wait till I bring my milling cradle down. Working on the ground is a pain in ass not to mention that even with the 9 pin it's still pulling the branch in.
 
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Absolution

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Did another run, somewhat better this time. I picked up the trunk this time and kicked a cookie under it to stop the nose from going into another log. Remove about two seconds from me cutting out throttle. I was already through it.


The picture of log was previous cut you could see where I was stopping.

Also if you watch the videos and see my head move its cause the cicadas are attracted to this saw and like to buzz me.

Edit: does anyone know if OEM clutches or another brand locks up better than huztl? It may be that I'm used to the 090 clutch.
 

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