STIHL MS461 BGD

[deye223]

Gday all just wondering how much success people have had with the 461 base gasket delete without any machine work how much squish did you end up with and will it work .

Cheers D

Ps i must be getting old I could have sworn I started a thread like this only days ago

 

[Wonkydonkey]

Have you seen the the mastermind meets the 461 thread

edit to add link
https://opeforum.com/threads/mastermind-meets-the-ms461.506/

 

[Wonkydonkey]

I did mine, it seems to have woken it up a little.

I went for the option of cutting a little off the piston, to get the intake duration. At the time I was told it would improve, but not the same as cutting the intake to get the duration. I was a bit new and nervous to it all and didn’t want to fugg the oem cylinder

I will go back into it at some point and do the cylinder. It’s just not high on my list.
Let us know how you get on.
btw I remember you asking about the coil and the 461..

 

[beaglebriar]

Shave the screw heads that hold the stuffer if you do a BGD.

 

[Wonkydonkey]

If you have a good read of randy's thread, it really is very informative. its all in there, inc drilling the main jet. I went on the conservative side of drilling it.

 

[deye223]

Thanks for the info anyway these are the three amigos 462 461 and MMSW460


The 460 that Randy did is a very angry toque Machine pulls harder than a 660 stock pulls 32 inch bar in Aussie hardwood no problem .
I figured bit by bit I will end up doing just about all of the 461 my first foray into modifying saws it is a lot of fun .

 

[ferris]

A member on AS wrote this, I think he knows a lot about 2 strokes:

I want to put to bed the myth of high compression in chainsaws,having worked on 2 stroke racing engines since the 70's I want to lay some straight facts down. High compression was first made popular during the 60's with big v-8 racing engines(4-stroke) and compression ratios went up to 13-1 or more. But the best 2-stroke racing engines actually reduced the compression ratio from the stock engines. Why,because the more the compression ratio the more horsepower it takes from the engine to crank the engine against that high compression,at some rpm the HP taken to crank that high compression takes more HP than it makes,and then the engine starts to lose HP. Thats why a factory motor making 60 HP at 8.5-1 compression,makes 100HP at 7.5-1 comp. ratio.
Now higher compression does make more power at low and mid range power for sure,but not many saws run in that range. so if you want more low end or mid range power compression is good,but if you need high rpm race power high compression will simply cost you Hp. As my instructor told me in 1975 "high compression fights high rpms",he was right.
So more more compression can help you,but not at high rpm's.
When you yank the cyl. gasket out of a saw you do gain some compression,BUT you also lower the exhaust and transfer ports down,reducing their duration,and reducing higher rpm power. I would much prefer to raise ports than compression for power,much more can be gained.
In many engines I would much prefer to raise the exhaust port and lose compression,I know I will make much more top end power.
Removing the cyl. gasket and lowering the transfer ports is really bad,you reduce their duration and reduce their open time from tens of thousanths of a second to even less!

what do u guys think about that?
Before I read this, I want to make a bgd but now I’m not sure if it is worth the time.

 

[ManiacalMark]

Is it low on compression? Have you done a muffler mod yet? Ported it?

 

[deye223]

Mmmm Deja vu

 

[deye223]

Is it low on compression? Have you done a muffler mod yet? Ported it?

If you're asking about that 461 no it's new it's only done 20 hours .
so far a muff mod unlimited coil timing advance .

 

[ManiacalMark]

Then just port it. I only thing I did to mine was ported it but it also had 180psi out of the box brand new. Lucky pick

 

[ferris]

Is it low on compression? Have you done a muffler mod yet? Ported it?

If u reply to my answer, not ported but muffler mod and timing advance.
About 60 tanks burned in that saw

 

[dustinwilt68]

A member on AS wrote this, I think he knows a lot about 2 strokes:

I want to put to bed the myth of high compression in chainsaws,having worked on 2 stroke racing engines since the 70's I want to lay some straight facts down. High compression was first made popular during the 60's with big v-8 racing engines(4-stroke) and compression ratios went up to 13-1 or more. But the best 2-stroke racing engines actually reduced the compression ratio from the stock engines. Why,because the more the compression ratio the more horsepower it takes from the engine to crank the engine against that high compression,at some rpm the HP taken to crank that high compression takes more HP than it makes,and then the engine starts to lose HP. Thats why a factory motor making 60 HP at 8.5-1 compression,makes 100HP at 7.5-1 comp. ratio.
Now higher compression does make more power at low and mid range power for sure,but not many saws run in that range. so if you want more low end or mid range power compression is good,but if you need high rpm race power high compression will simply cost you Hp. As my instructor told me in 1975 "high compression fights high rpms",he was right.
So more more compression can help you,but not at high rpm's.
When you yank the cyl. gasket out of a saw you do gain some compression,BUT you also lower the exhaust and transfer ports down,reducing their duration,and reducing higher rpm power. I would much prefer to raise ports than compression for power,much more can be gained.
In many engines I would much prefer to raise the exhaust port and lose compression,I know I will make much more top end power.
Removing the cyl. gasket and lowering the transfer ports is really bad,you reduce their duration and reduce their open time from tens of thousanths of a second to even less!

what do u guys think about that?
Before I read this, I want to make a bgd but now I’m not sure if it is worth the time.

I would ask what is the optimal compression for this model? Not every two stroke is the same, and are we talking just moving the compression and leaving the numbers where they are without the gasket? Or are we talking about increasing compression and moving the numbers like most of us do when porting a saw? To me it comes down to results, after porting this model really wakes up, that I am certain of. Lot of guys on here have ported 461s with great results, I would bet most of them have increased compression.

 

[huskyboy]

A member on AS wrote this, I think he knows a lot about 2 strokes:

I want to put to bed the myth of high compression in chainsaws,having worked on 2 stroke racing engines since the 70's I want to lay some straight facts down. High compression was first made popular during the 60's with big v-8 racing engines(4-stroke) and compression ratios went up to 13-1 or more. But the best 2-stroke racing engines actually reduced the compression ratio from the stock engines. Why,because the more the compression ratio the more horsepower it takes from the engine to crank the engine against that high compression,at some rpm the HP taken to crank that high compression takes more HP than it makes,and then the engine starts to lose HP. Thats why a factory motor making 60 HP at 8.5-1 compression,makes 100HP at 7.5-1 comp. ratio.
Now higher compression does make more power at low and mid range power for sure,but not many saws run in that range. so if you want more low end or mid range power compression is good,but if you need high rpm race power high compression will simply cost you Hp. As my instructor told me in 1975 "high compression fights high rpms",he was right.
So more more compression can help you,but not at high rpm's.
When you yank the cyl. gasket out of a saw you do gain some compression,BUT you also lower the exhaust and transfer ports down,reducing their duration,and reducing higher rpm power. I would much prefer to raise ports than compression for power,much more can be gained.
In many engines I would much prefer to raise the exhaust port and lose compression,I know I will make much more top end power.
Removing the cyl. gasket and lowering the transfer ports is really bad,you reduce their duration and reduce their open time from tens of thousanths of a second to even less!

what do u guys think about that?
Before I read this, I want to make a bgd but now I’m not sure if it is worth the time.

A simple base gasket delete is usually a gain on most saws. I do think that once you go past say maybe 190-210psi (from machine work)... it seems to just add more heat to the saw. Which makes it touchier to tune (especially with lots of intake duration)... and more difficult to start/harder on recoil parts. The more compression you add, the less the saw seems to like timing advance. Then there is the question of bottom end longevity. Does that mean more compression is bad? Not necessarily. It’s just what I have noticed from using a saw from a work standpoint. I’m sure the answer will vary depending on the saw and what your using it for.

 

[Wonkydonkey]

Also bgd, is an easy way to get a better squish size, which also means more power as more of the fuel is pushed into the combustion area
IMO, it’s a winner.

 

[huskihl]

Usually the flange screws on the 461 stick up proud of the base and will need to be ground off slightly so the base can sit down without a gasket

 

[ManiacalMark]

A simple base gasket delete is usually a gain on most saws. I do think that once you go past say maybe 190-210psi (from machine work)... it seems to just add more heat to the saw. Which makes it touchier to tune (especially with lots of intake duration)... and more difficult to start/harder on recoil parts. The more compression you add, the less the saw seems to like timing advance. Then there is the question of bottom end longevity. Does that mean more compression is bad? Not necessarily. It’s just what I have noticed from using a saw from a work standpoint. I’m sure the answer will vary depending on the saw and what your using it for.

Yup, too much intake duration makes it hard or almost impossible to tune and sluggish throttle response.

Getting into higher compression on a worksaw I've played with retarding the ignition timing some and it actually worked quite well. Advance the timing too much on an early 066 with 240 psi and watch what happens not long after the rings seat....that made for a bad day cutting logs.

 

[smokey7]

A high compression saw will teach you to get the saw good and warm before you do anything to the tune. I have one here that if you didn't wait you would be chasing the tune as it warms up. Starts out fat as hell then once warm it's perfect.

 

[deye223]

A high compression saw will teach you to get the saw good and warm before you do anything to the tune. I have one here that if you didn't wait you would be chasing the tune as it warms up. Starts out fat as hell then once warm it's perfect.

I will definitely agree with that.
Every time I start it for the first time of the day it just bellos smoke and yeah runs fat as once she's warmed up totally different story opposite end of the scale

 

[John7478]

I will definitely agree with that.
Every time I start it for the first time of the day it just bellos smoke and yeah runs fat as once she's warmed up totally different story opposite end of the scale

Where do you buy your Mobil 1 2t from?