Dolmar 64xx/73xx/79xx series, smurfs and solo 665/675/681 thread

[kingOFgEEEks]

Do you have a picture of the chunk out of the exhaust port?

Depending on how bad it is, it might be a good candidate for a 681 stroker with the base and squish cut, and through raising the exhaust accordingly it might get cut out.

It's taking a bath in the USC right now. I'll snag a pic when it comes out.

 

[MustangMike]

From what I understand, the top of the exhaust port is not as critical as the bottom, so after cleaning it up and smoothing any boogers, you might have a good backup!

I disagree; the port opens from the top. Unless you want to change the port timing, it is critical. It can be restored if you cut the base or build w/o a base gasket, but the rest of the ports would have to be modified. It is always important to have a little curve on the ports and proper beveling to help prevent ring hang ups. That said, if the ring broke first, nothing would help.

Sending it to a porter that can do all these things (including moving the other ports, if necessary) would likely be a wise choice, and then you would have a ported saw!

 

[kingOFgEEEks]

It’s pretty ugly.
Intake side:
Exhaust:


There’s a big chunk of plating missing below the exhaust port, as well as the damage above.

 

[hacskaroly]

I disagree; the port opens from the top. Unless you want to change the port timing, it is critical.

Good to know, I learned something!!

 

[Powerstroke Cowboy]

It’s pretty ugly.
Intake side: View attachment 447903
Exhaust:
View attachment 447904

There’s a big chunk of plating missing below the exhaust port, as well as the damage above.

Thanks for the pictures. The exhaust is worse than I thought it might be.

As long as the plating does not keep peeling it could be made to work again.

Looks like a good cylinder to try an extreme base a squish cut with a stroker crank and see what happens. Might be able to make a hot saw out of it.

 

[SOS Ridgerider]

This thread needs a bump. Been months since the last post, and these saws are too good, and too much fun, to let this thread die.
Here’s a 6400 with a closed port Solo 665 top end, so it’s now a 64cc closed port.
The 6400 piston is still used, as the height from pin to top of piston is slightly taller than on the Solo piston, so less had to be taken off the base to get squish around .020”.
I feel like this is how these saws should have been to start with, but this will be a fun one.
As you can see I’ve left everything alone, and just plugged the decomp. The top cover is untouched.
I still have to gut the muffler, and slot the upper mount holes.

Props to @huskihl for doing the machine work on the base for me.
This saw has been together for a couple of years now, but I haven’t gotten around to doing the last touches to get it ready.

Edit: I had the pistons mistaken. The Dolmar piston is taller than the Solo piston. @David Young Thanks for catching my mistake.

 

[Squareground3691]

 

[David Young]

This thread needs a bump. Been months since the last post, and these saws are too good, and too much fun, to let this thread die.
Here’s a 6400 with a closed port Solo 665 top end, so it’s now a 64cc closed port.
The 6400 piston is still used, as the height from pin to top of piston is slightly lower than on the Solo piston, so less had to be taken off the base to get squish around .020”.
I feel like this is how these saws should have been to start with, but this will be a fun one.
As you can see I’ve left everything alone, and just plugged the decomp. The top cover is untouched.
I still have to gut the muffler, and slot the upper mount holes.

Props to @huskihl for doing the machine work on the base for me.
This saw has been together for a couple of years now, but I haven’t gotten around to doing the last touches to get it ready.

I feel like I am missing something here. The Dolmar has a 1mm shorter stroke so i understand that the base needs to be cut but don't understand the benefit of the Dolmar piston in the solo cylinder. must be the dimensions are different? do you have any pics side by side?

 

[David Young]

View attachment 463455View attachment 463457

I love the axes hanging on the wall

 

[Squareground3691]

I love the axes hanging on the wall

Thanks David ,

 

[SOS Ridgerider]

I feel like I am missing something here. The Dolmar has a 1mm shorter stroke so i understand that the base needs to be cut but don't understand the benefit of the Dolmar piston in the solo cylinder. must be the dimensions are different? do you have any pics side by side?

From what I recall, the pistons are almost the same, except for the slight height difference.

Wait a minute... I feel like I have it backwards, and that the Dolmar piston is taller, which would make a lot more sense why I did it this way. Less would have to be taken off the base that way, which was the whole point.
It's been over 2 years since I messed with this, and my memory is, obviously, pretty much stellar. Plus I'm clearly a genius

I can probably get a side by side pic. I'm sure I have pistons for both kicking around somewhere.

I believe you're correct David, and I have it backwards. I edited my original post.

 

[David Young]

cool I have a 6400 that came from CT
and a 665 set up I think that would be a fun project. Did you port it too or just put the better top on it?

 

[David Young]

From what I recall, the pistons are almost the same, except for the slight height difference.

Wait a minute... I feel like I have it backwards, and that the Dolmar piston is taller, which would make a lot more sense why I did it this way. Less would have to be taken off the base that way, which was the whole point.
It's been over 2 years since I messed with this, and my memory is, obviously, pretty much stellar. Plus I'm clearly a genius

I can probably get a side by side pic. I'm sure I have pistons for both kicking around somewhere.

I believe you're correct David, and I have it backwards. I edited my original post.

I will no longer call you sombrero. from now on you will be referred to as genius.

 

[huskihl]

From what I recall, the pistons are almost the same, except for the slight height difference.

Wait a minute... I feel like I have it backwards, and that the Dolmar piston is taller, which would make a lot more sense why I did it this way. Less would have to be taken off the base that way, which was the whole point.
It's been over 2 years since I messed with this, and my memory is, obviously, pretty much stellar. Plus I'm clearly a genius

I can probably get a side by side pic. I'm sure I have pistons for both kicking around somewhere.

I believe you're correct David, and I have it backwards. I edited my original post.

I can’t remember what all we did either. I know (think) we went both ways with hybrids. Did I put Dolmar cylinders on Solo’s and machine a Solo cylinder for you to put on a Dolmar? I do remember the issues with the piston but can’t remember details

 

[Wilhelm]

I will no longer call you sombrero. from now on you will be referred to as genius.

 

[SOS Ridgerider]

I will no longer call you sombrero. from now on you will be referred to as genius.

I would expect nothing less!

 

[SOS Ridgerider]

I can’t remember what all we did either. I know (think) we went both ways with hybrids. Did I put Dolmar cylinders on Solo’s and machine a Solo cylinder for you to put on a Dolmar? I do remember the issues with the piston but can’t remember details

You're correct. There were two Solo 665's that got Dolmar top ends. One got a 7300 top end, and the other a 7900.

The SOLO top end, that came off one of those saws, you machined the base on to fit on a 6400 Dolmar. I remember the piston issues as well, and I think David is correct. The Dolmar piston required less off the base, so we went with that.

 

[SOS Ridgerider]

cool I have a 6400 that came from CT
and a 665 set up I think that would be a fun project. Did you port it too or just put the better top on it?

I remember that saw. Lol
I didn't do any port work to it. I have the equipment to do it, but I don't know my ass from my elbow with port work yet, so maybe later.
Gutting the muffler, and adding an outlet, will be the first I need to do. I'll need some more advice before the Foredom hits the cylinder. Lol

 

[Wood Doctor]

6100 is an outlier. There are no interchangeable parts with other models, it’s a strato with a reed valve. It has a 35mm stroke. Right now parts are relatively available, but they won’t be forever. They do seem to be very nice saws though.

The 64-79xx platform is more versatile and abundant. Bigger for roughly the same price. That might be a better gateway drug.

I suppose so. My "outlier" keeps going and going:
I love this saw. I replaced the top end with a big bore kit. That made it a monster. The 32" bar and chain is shown here.

 

[Wilhelm]

Stock OEM 50mm & 52mm handle a 36" 115DL 3/8" fully buried with no issues!
Both bucking & noodling.
Just saying.