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

[mettee]

View attachment 344492

anyone wanna trade red for teal carb tray?

I'll look I might have an extra

 

[mettee]

 

[whitesnake]

View attachment 344492

anyone wanna trade red for teal carb tray?

That’s an interesting muffler mod you got there.

 

[mettee]

That’s an interesting muffler mod you got there.

That's the oxidation mod

 

[davidwyby]

I think she's beautiful.

We'll see what we can do with it...

 

[sledneck22]

So I just bought my first dolmar. 7910 off a feller on this site. It’s gonna need a piston. There ain’t snit for pistons available. What’s everyone using?
Or does anyone have one they’d like to sail?
I’m excited to see what all the fuss is about with these saws.

 

[huskihl]

So I just bought my first dolmar. 7910 off a feller on this site. It’s gonna need a piston. There ain’t snit for pistons available. What’s everyone using?
Or does anyone have one they’d like to sail?
I’m excited to see what all the fuss is about with these saws.

I know they aren’t very popular on here, but I put probably 50 tanks through my ported 7900 with a Golf piston in it. They are quite similar to OEM, but I would use better circlips than what any of the Chinese or Taiwan pistons come with

 

[mettee]

So I just bought my first dolmar. 7910 off a feller on this site. It’s gonna need a piston. There ain’t snit for pistons available. What’s everyone using?
Or does anyone have one they’d like to sail?
I’m excited to see what all the fuss is about with these saws.

I'll send you a few pics of one I have

 

[Wilhelm]

I have a white box AM piston in my PS-6400, works perfectly fine.
Caber piston ring and OEM circlips though.

 

[davidwyby]

@sledneck22 I haven’t run a stock one but my XS is a monster. I’d be a lot more OK with an AM piston than an AM cyl. Esp if these other fellers ok ‘em.

 

[sledneck22]

Thanks for everyone’s recommendations. @mettee helped me out with a nice used one.
Watch around, I’ll post some build pictures.
What’s everyone find for stock squish and base gasket delete.

 

[sledneck22]

Thanks for everyone’s recommendations. @mettee helped me out with a nice used one.
Watch around, I’ll post some build pictures.
What’s everyone find for stock squish and base gasket delete.

 

[Steve]

Thanks for everyone’s recommendations. @mettee helped me out with a nice used one.
Watch around, I’ll post some build pictures.
What’s everyone find for stock squish and base gasket delete.

I was too tight with a bgd. Around .010 or .011.

 

[huskihl]

Thanks for everyone’s recommendations. @mettee helped me out with a nice used one.
Watch around, I’ll post some build pictures.
What’s everyone find for stock squish and base gasket delete.

Been .010” - .013” at the outer edge on all of them without gasket

 

[mettee]

I found the 16oz Curs light twist off aluminum is about 010.



My normal Dew can is thinner.

 

[sledneck22]

So to follow up on my Dolmar build. The piston that @mettee supplied me cleaned up nice with a little 400grit paper. Smoothed right out. The cylinder did have a lot of transfer but that also cleaned up nicely. Just a lot more work involved.
Why I'm here again, I checked and double checked and I was getting around .040-.045 of squish with the base gasket. Without base gasket I was getting around .028. Multiple angles, multiple test. I was expecting there to be much less. It's a mahle cylinder with three +'s. Was there potentially work done to this cylinder? Or am I missing something else? Does anyone have any pictures of a stock 7910 cylinder? I cleaned up and polished the lowers, slightly widened the exhaust, and cleaned up the bevels as well. It looks like the flanges of inside of the lowers had funny sweeps cut into it for flow from the bottom end. But looked factory. Just looking to compare at this point. I motosealed and clamped on the top end last night so regardless I'm going to see how it runs as is.

 

[Wilhelm]

I have a OEM NIB NOS PS-7900 P&C kit stashed away.
Would pictures of that one help.

I have no 7910 P&C, neither used nor new.

 

[sledneck22]

I have a OEM NIB NOS PS-7900 P&C kit stashed away.
Would pictures of that one help.

I have no 7910 P&C, neither used nor new.

I wouldn't mind having a peak if it's easy to un-stash. if it's a pain, then I wouldn't bother. Thank you for offering regardless of what direction you so choose.

 

[mettee]

So to follow up on my Dolmar build. The piston that @mettee supplied me cleaned up nice with a little 400grit paper. Smoothed right out. The cylinder did have a lot of transfer but that also cleaned up nicely. Just a lot more work involved.
Why I'm here again, I checked and double checked and I was getting around .040-.045 of squish with the base gasket. Without base gasket I was getting around .028. Multiple angles, multiple test. I was expecting there to be much less. It's a mahle cylinder with three +'s. Was there potentially work done to this cylinder? Or am I missing something else? Does anyone have any pictures of a stock 7910 cylinder? I cleaned up and polished the lowers, slightly widened the exhaust, and cleaned up the bevels as well. It looks like the flanges of inside of the lowers had funny sweeps cut into it for flow from the bottom end. But looked factory. Just looking to compare at this point. I motosealed and clamped on the top end last night so regardless I'm going to see how it runs as is.

Try measuring with 4 pieces of solder and continue to turn it over until the solder no longer creates resistance. Measure each one and keep them in the same position so you can know each position.

If there is resistance still you are not measuring the real squish

 

[sledneck22]

I did that. Even cut some small chunks of solder and held them in place with grease along the perimeter of the piston and reinstalled the cylinder. Those are where my measurements came from.