Logosol Beastie Solo 603 build

[Iron.and.bark]

I found this wee little 603 languishing in a dealers back room sporting a shattered piston, crushed handle, and barely salvageable cylinder. It also sported a lovely tag saying it was from a local earth moving business.

Needless to say I paid to much for a Nos piston (is Australian dealer OEM piston prices). Ran it abit and love it, even better than my much beloved solo 690.

Quick little pic of it sitting on the logosol



Cut myself some nice timber, but something was not quite right. So off with the cylinder head and let's play a little.

These are unusual because they have removable transfer ports





Didn't think to take before pics, so here's what I have done so far.

Exhaust


Intake.

 

[Iron.and.bark]

The intake is abit of a pain because of these bolt holes.



Was able to remove a lot of meat around them though, but they go so deep makes it abit beyond my safety margin to flare intake more.



Widened the exhaust exit, but it ain't perfect yet.

On a side note, this saw was totalled. I know it's a rare saw, but it is way beyond any collectors condition. Prob have to replate the cylinder soon to.

Also anyone here have a 066 big bore piston, would love to know the skirt width.

 

[bryanr2]

subbed

 

[rocco490]

awesome glad someone is porting one of these!

 

[ajschainsaws]

It's a shame there isn't more parts around to have a play

 

[Iron.and.bark]

Gutted the muffler and enlarged entrance. Yes it does look rough



Baffle that goes over exit. Will probably make a slightly larger one later.



Now here is where we had a problem. The removably transfers were sealed with an o ring, which had split leaving an imperfect seal. I glued some o ring material in place, then put some yamma bond on to ensure a good seal.



Transfers aren't being touched at present as I want a torque heavy milling saw.

I will how ever make some new removable transfers and experiment with both reducing and increasing the volume once I get some suitable ally blocks.

 

[Miller Mod Saws]

It's a shame there isn't more parts around to have a play

What you talking about. One right here for sale. Lol.

 

[Miller Mod Saws]

Gutted the muffler and enlarged entrance. Yes it does look rough

View attachment 31492

Baffle that goes over exit. Will probably make a slightly larger one later.

View attachment 31493

Now here is where we had a problem. The removably transfers were sealed with an o ring, which had split leaving an imperfect seal. I glued some o ring material in place, then put some yamma bond on to ensure a good seal.

View attachment 31494

Transfers aren't being touched at present as I want a torque heavy milling saw.

I will how ever make some new removable transfers and experiment with both reducing and increasing the volume once I get some suitable ally blocks.

Good thread!

 

[Iron.and.bark]

Thanks for the feedback all, it's appreciated.

Is a pity there isn't more of these around, but the solo 690 had almost as much torque and it revs quicker. I will post a pic comparing the transfers of both tomorrow.

Was a lot of solo 690's sold in this neck of the woods, just bloody hard to get anyone to part with them. Not surprising as they kill a 395xp in the wood over here.

 

[jacob j.]

I think what hurt the 603 is how large they made the transfers. With a 28" or smaller bar, my 680 stays right with a 603, all other factors being fairly equal. I'll be doing some 603 rebuilds here soon and I think I'll try stuffing the crank and transfers to get the charge velocity up.

 

[ajschainsaws]

Gutted the muffler and enlarged entrance. Yes it does look rough

View attachment 31492

Baffle that goes over exit. Will probably make a slightly larger one later.

View attachment 31493

Now here is where we had a problem. The removably transfers were sealed with an o ring, which had split leaving an imperfect seal. I glued some o ring material in place, then put some yamma bond on to ensure a good seal.

View attachment 31494

Transfers aren't being touched at present as I want a torque heavy milling saw.

I will how ever make some new removable transfers and experiment with both reducing and increasing the volume once I get some suitable ally blocks.

What you talking about. One right here for sale. Lol.

What you talking about. One right here for sale. Lol.

Nice one Carl how much haha

 

[Iron.and.bark]

I think what hurt the 603 is how large they made the transfers. With a 28" or smaller bar, my 680 stays right with a 603, all other factors being fairly equal. I'll be doing some 603 rebuilds here soon and I think I'll try stuffing the crank and transfers to get the charge velocity up.

Comparing the transfers between the 690 and 603 I would be more inclined to think it's not just the size, but the "flow" would reduce the velocity of the charge.

I think I will try and copy the 690 design (as well as I can) where the charge is seperated through the whole length of the transfers instead of being mixed till almost point of exit in the uppers.

 

[Iron.and.bark]

Solo 690 lowers



Solo 603 lowers



Here they are side by side



Makes you wonder why solo used removable transfers on the 603. Since it's the same case, and same cylinder foot print. Perhaps cylinder wall was to thin at the transfers?

Assuming there isn't an wall thickness issue, maybe a 690 jug bored to 56mm put on the 603 might make an even better saw. Have to accommodate the 603 longer stoke though.

 

[Wilhelm]

... Makes you wonder why solo used removable transfers on the 603. Since it's the same case, and same cylinder foot print. Perhaps cylinder wall was to thin at the transfers? ...

Easier cylinder casting and processing with lesser junk casts not passing QC would be my guess.

I work in a cast iron factory and we (read: the factory I work in) used to make "hollow" casts using sand cores.
With the purchase of faster more automated equipment we abandoned hollow casting and since altered remaining formerly hollow cast products to multi part casts that require assembling after processing.
I know what some of You are thinking, that we are going backwards - You are right to a certain point!
Hollow casting is more time consuming throughout the entire manufacturing process. Manufacturing multiple individual "simpler" parts is less costly and faster even though there are up to several individual casts instead of a single one.

Nice thread!
That cylinder looks quite scored, amazing what will still run.

 

[Iron.and.bark]

Progress so far.



Cylinder head back on, base gasket delete, measured 34 thou clearance.

 

[Iron.and.bark]

Easier cylinder casting and processing with lesser junk casts not passing QC would be my guess.

I work in a cast iron factory and we (read: the factory I work in) used to make "hollow" casts using sand cores.
With the purchase of faster more automated equipment we abandoned hollow casting and since altered remaining formerly hollow cast products to multi part casts that require assembling after processing.
I know what some of You are thinking, that we are going backwards - You are right to a certain point!
Hollow casting is more time consuming throughout the entire manufacturing process. Manufacturing multiple individual "simpler" parts is less costly and faster even though there are up to several individual casts instead of a single one.

Nice thread!
That cylinder looks quite scored, amazing what will still run.

Thanks for the input.

Have cleaned the cylinder up more, still far from perfect.

I just find it strange. You are probably correct with it being a quality control issue.

Have done some more measuring. The more I measure the more I think I should overbore an 690 cylinder rather than replate the 603 (for my use, removable transfer would make a mean race saw).

Have measured the wall thickness at the transfers and is 4.5mm on 690 and 3.5mm on 603 at widest points.

Secondly the height of the cylinder transfers wall section differs between the 603 and 690. With the 690 being 6.5mm from cylinder base, and 603 being 10.5mm.

 

[Iron.and.bark]

Flywheel key shaved. Might have been a little aggressive in the timing advance here, but will see. Wanted to start at about 4°, but I guess it will be closer to 6° advance.



No more tonight, need to find a 1/4 drive 8mm socket (is shop tomorrow) to adjust coil gap.

Also recon I better recheck the squish band clearance, as 34 thou seems a lot larger than it should be, may have used to thick a solder to check it with.

 

[Iron.and.bark]

Here's a quick pic, big clutch eh?



10 tooth .325 sitting in front of the saw, need to add a couple of links to fit it. interesting to see how well this saw handles it compared to the 3120.

Anyway fired the saw up, not happy with the carb. Need to run a kit through it I think. Sounds nice and loud though, dirt bike time

 

[ajschainsaws]

Yeh huge clutch you may find it'll develop a lot of heat clutch side my other 603 used too burn the clutch cover

 

[Iron.and.bark]

This thing already has a 3/4 circle burnt through around the clutch cover unfortunately

Got a new chain made, will fit the 10 tooth and see how she goes. Can't get a tune I like on it yet though :/