Carbtard

[NateSaw]

I find center of the plate and then use a base gasket to set the holes. After making a bunch of plates, you’ll find that most saws will fit what you have made with a few exceptions. Then I just stamp and “E” and the model on the exhaust side of the plate.

For instance, am 066 and a 395 can use the same plate, the 395 just needs to be rotated 90*.

Like Kev says above, your center can be off. But if it’s off too much it will cause a wobble when it’s spinning which always worries me, especially when I want to make a higher rpm final band cut on autofeed.

I'm finding great finish by taking a spring pass as my final. It's like a half a thou, and typically shines up with zero chatter, as it's taking so little. I do it at low speeds. I too am leary of high speeds. Especially on the Jugs resting on small sockets.

 

[NateSaw]

Both band and base finished with a spring pass, rotating compound dial by hand

 

[NateSaw]

This might show base better.

 

[NateSaw]

I don’t use the tailstock or a mandrel to center or dial in the jug in the 4 jaw so not certain. I use a long reach dial indicator on the x and y axis inside the jug

I just went for it on the 361. Used gasket and eyeballed center to mark holes on plate. Blasted em and chucked up on lathe and was centered and cutting in a half hour. I could complicate a fart. I've been wasting hours trying to make the plates perfect.

 

[pbillyi69]

all of this info on this thread is really good and why i pay other people to port my saws. im a professional overthinker

 

[NateSaw]

Back to carb stuff. 461 airhorn saves the day again. I'm fixing to eliminate that plastic elbow inlet horn abomination these 361's carry all together.
Fits with heavy modification. I'm thinking the HD 50a off the 461 lends itself better than a 440 carb, as the throttle cam is on the right side. Talked to @drf256 about it, and Doc pointed out that the impulse nipple would interfere with the throttle linkage. I'd like to try and drill the impulse passage into the 50a's body, then I'd just need to swap plates, and keep the 361 intake boot. Has anyone tried similar?

 

[NateSaw]

Earlier this year I ported a 362 that wouldn't behave after the port job. The saw was consistently going lean, and the owner sent it back to me. After running some test cuts, I quickly concluded the carb was starving for fuel under load. I pulled the m-tronic solenoid as you did, and I found the orifices to be around 0.045". The needle seat was only 0.023". I made the decision to drill out the needle seat to 0.033" and polished it. I put the saw back together and life was good. The saw actually was a touch fat on top until the m-tronic dialed in the tune....it also picked up a good amount of mid-range power after the carb mod. IIRC, I took 0.045" from the band, advanced the timing ~8 degrees, and had 106, 124-127, 78. It was easily the strongest 60cc I have built so far.

When I get the boss man's 362 back, I'm going to run your recipe. Thank you!

 

[NateSaw]

@farminkarman , @huskihl , @Ketchup , @drf256 ,anyone else on here.. My maths has me taking another 42thou off base of this ms362 to bring the exh down to 106*. I took 16thou to go from the stock (no gasket) 100.5*, to 102*. Does a total of 58thou seem to correspond with anyone's else's notes aiming for 106* exh on these saws? Self doubt in my maths has overcome. Interestingly enough, that doesn't land int at 78*. I'd have to take another 57thou to hit that, making for a total removed of 73thou. Seems like alot of base! My goal is to keep uppers nice and tight, so I was hoping to avoid raising exh. I appreciate you fellers. Thanks in advance!

 

[huskihl]

@farminkarman , @huskihl , @Ketchup , @drf256 ,anyone else on here.. My maths has me taking another 42thou off base of this ms362 to bring the exh down to 106*. I took 16thou to go from the stock (no gasket) 100.5*, to 102*. Does a total of 58thou seem to correspond with anyone's else's notes aiming for 106* exh on these saws? Self doubt in my maths has overcome. Interestingly enough, that doesn't land int at 78*. I'd have to take another 57thou to hit that, making for a total removed of 73thou. Seems like alot of base! My goal is to keep uppers nice and tight, so I was hoping to avoid raising exh. I appreciate you fellers. Thanks in advance!

Don’t know how much I remove from the base as that’s done in increments to get squish where I want it. But I usually take .040 - .050” from the squish

 

[NateSaw]

Don’t know how much I remove from the base as that’s done in increments to get squish where I want it. But I usually take .040 - .050” from the squish

Thanks Kevin. I think my maths is wrong. I'm bad at maths. I have to be careful. I've been using online piston position calculators. I only got to use torque soft once, and it brought me to the 102 point with absolute precision. However, that software apparently no longer exists. So I'm trying this one :

https://www.vcalc.com/wiki/EmilyB/Position+of+the+piston+of+engine+with+respect+to+crank+angle

However it works with crank radius rather than stroke, which adds another step of division. I had initially found stroke and rod length using rather jurassic methods. I came up with a 57mm rod and a 34mm stroke.

 

[Ketchup]

You might be complicating your farts again. How much did you already drop the jug and how much exhaust did you gain? Where would you be if you did that again? Careful not to freeport.

Don’t worry about the intake. Get your exhaust right and keep your uppers tight-ish. You can grind more intake very easily, but you probably don’t need it. I generally like higher uppers and higher intake. Opinions vary.

Your current numbers have a lot of blowdown. The slanted uppers don’t open with the same volume so they can crack earlier. Especially since they’re staggered. Personally, I feel like the 362 uppers are over engineered. Cutting them flat at a blowdown of 20primary/22secondary worked well for me, but it’s not a saw I work with often.

 

[farminkarman]

Don’t know how much I remove from the base as that’s done in increments to get squish where I want it. But I usually take .040 - .050” from the squish

I take 0.045” from the band….also don’t know what I cut from the base.

 

[NateSaw]

You might be complicating your farts again. How much did you already drop the jug and how much exhaust did you gain? Where would you be if you did that again? Careful not to freeport.

Don’t worry about the intake. Get your exhaust right and keep your uppers tight-ish. You can grind more intake very easily, but you probably don’t need it. I generally like higher uppers and higher intake. Opinions vary.

Your current numbers have a lot of blowdown. The slanted uppers don’t open with the same volume so they can crack earlier. Especially since they’re staggered. Personally, I feel like the 362 uppers are over engineered. Cutting them flat at a blowdown of 20primary/22secondary worked well for me, but it’s not a saw I work with often.

I currently have 26* of blowdown. I took 16thou off base to get to 102*,but that's minus gasket. One of the reasons I don't want to raise the exh Is free porting. Using the calculator, I can see piston pin position @ 2.007" for 102* exh, and if I were to lower jug to achieve 78* intake. Seeing that crossover concerned me. That's when the bulb went off in my head as I noticed the tab on the skirt, intake side. In my mind it appears to be close to Freeport already.

 

[NateSaw]

I take 0.045” from the band….also don’t know what I cut from the base.

Seems my focus needs to shift from dropping jug to achieve later exh, to doing whatever is needed to get a desirable squish band... I remember reading a percentage number in one of the threads in here. I'm picking up from alot of you guys that most of the magic is in the squish?

 

[huskihl]

Seems my focus needs to shift from dropping jug to achieve later exh, to doing whatever is needed to get a desirable squish band... I remember reading a percentage number in one of the threads in here. I'm picking up from alot of you guys that most of the magic is in the squish?

I’ve heard of others dropping x amount to make this number or that number work out or land “perfectly”. After 1000 saws there are so many possibilities that “perfect” only exists in the head of the person doing the calculations. There’s always one better, one faster, one with more torque….

I cut squish to add compression and/or to get the exhaust down. If I’d like to hit a number but miss by 1 or 2°, it is what it is.

 

[huskihl]

I'm bad at maths.

I consider myself pretty good with math. But doing all that would spoil it for me. In the end, there’s no program that works to make a saw run how you think it should run. There is just practice

 

[NateSaw]

I’ve heard of others dropping x amount to make this number or that number work out or land “perfectly”. After 1000 saws there are so many possibilities that “perfect” only exists in the head of the person doing the calculations. There’s always one better, one faster, one with more torque….

I cut squish to add compression and/or to get the exhaust down. If I’d like to hit a number but miss by 1 or 2°, it is what it is.

"perfect" and/in this head is an oxymoron
I guess my aim is to be accurate. Being that I'm so green to all of this, I may be picking less than perfect goals. I've no idea what I'm chasing... But I suppose if my theory is to keep the uppers as tight as possible, and land the exh where I want it, I have less material to remove to raise the uppers to achieve a recommendation for blowdown. Thereby, in my theoretical world, I have less to remove from lowers (if any, as with perhaps a dual port jug) to have a gradient, smooth path from a slightly larger area, to a smaller area to facilitate velocity at the uppers. As far as intake goes, I like the idea of less is more, at least to start. I've learned from you guys the value of maintaining case compression, and vacuum, in many cases. I've a feeling my dislexia has me working backwards from how most of you fellers do. I work the band up, in my math, after determining the base. So for my methodology, the band is a symptom of landing timing. But I digress, I think my math is fugged up on this one.

 

[NateSaw]

I consider myself pretty good with math. But doing all that would spoil it for me. In the end, there’s no program that works to make a saw run how you think it should run. There is just practice

No sir. It's just a calculator to help me land where my fruity ass THINKS it'll run good. The calculator is so I don't have to do this formula:

Because I'm embarrassed to admit, I can't do that formula. I never got that far in math. I simply couldn't do math. I left high school my junior year bacause I simply could not learn algebra and beyond. I acquired my good enough diploma with a Casio calculator. And I assure you no formula like that was on the test.

 

[NateSaw]

Also, I'm quite dislexic. Or at least, it seems that way.

 

[huskihl]

"perfect" and/in this head is an oxymoron
I guess my aim is to be accurate. Being that I'm so green to all of this, I may be picking less than perfect goals. I've no idea what I'm chasing... But I suppose if my theory is to keep the uppers as tight as possible, and land the exh where I want it, I have less material to remove to raise the uppers to achieve a recommendation for blowdown. Thereby, in my theoretical world, I have less to remove from lowers (if any, as with perhaps a dual port jug) to have a gradient, smooth path from a slightly larger area, to a smaller area to facilitate velocity at the uppers. As far as intake goes, I like the idea of less is more, at least to start. I've learned from you guys the value of maintaining case compression, and vacuum, in many cases. I've a feeling my dislexia has me working backwards from how most of you fellers do. I work the band up, in my math, after determining the base. So for my methodology, the band is a symptom of landing timing. But I digress, I think my math is fugged up on this one.

Uppers….I keep them in mind but don’t let them change my mind too much. Actually a 660 is about the only saw that comes to mind that is “fussy” about larger uppers. I’m certain that it matters on others but I haven’t noticed. Most 3 series huskies get raised 6-8” after lathe work. Going off memory, most 044-046 get raised way up after, same as 361’s and 362’s