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

[mettee]

Had a guy do a couple 5-6 spot welds on my muffler yesterday. Got it home and looked at it, the shells had shifted and he welded it that way and ruined the whole thing. Trying to salvage it but it's not pretty. Booger city out of a GTAW.... WTF.

The welds had to be ground.

Now I have to buy a machine and do this myself.

 

[huskyboy]

Had a guy do a couple 5-6 spot welds on my muffler yesterday. Got it home and looked at it, the shells had shifted and he welded it that way and ruined the whole thing. Trying to salvage it but it's not pretty. Booger city out of a GTAW.... WTF.

The welds had to be ground.

Now I have to buy a machine and do this myself.

You uncrimped it then spot welded it back together? I just uncrimped mine and crimped it back together no problems. Or are you talking about the internal back plate from slr you cut off then welded back in?

 

[mettee]

Yeah there are four sections, I put back the rear shell and tried to spot tack it in. Well not me, the guy who is a welder with an 8k dollar Miller. If you leave it out the rear section that mates to the cylinder carries all the weight and I bet it cracks. I know there is a front brace but it not worth just leaving that inner baffle out. Plus it's another layer of stainless to deflect heat and keep it off the cylinder.

And yes I uncrimped it all very carefully and it was in perfect shape

 

[huskyboy]

I lucked out that the 7900 muffler is easier than the slr and cat style mufflers to uncrimp. The backplate on 7900 muffler can be cut off the cage and sandwiched between the studs/shell the way it was easily. I can see the 7910 style maybe needing welded with that back plate?

 

[mettee]

I drilled a couple holes around the outside and a couple inside. The thick brace is mild steel so the stainless doesn't like to stick.

Inside of the second shell.

Should be doable, hell I've done this before and I'm a sucky finger burning hand shocking rookie.

It was all cleaned too.

 

[mettee]

If yall get sick of pictures let me know.

The disaster. Shell was twisted so it would not go into the front half.

Got it out, thank God I got a good small carbide burr and the welds were visible.

I had a second busted muffler I picked up from a member here for a case of brewkies.

Back in business after some tweaking and hammering and I got the shell to fit.

Next time if I have a guy help, I'll say hey you test on this.

Stock port is stock. Real small, I'll match it back up.

 

[NCFarmboy]

I wonder if they moved it to the side to improve wear characteristics?

Can't see where that would help wear. Case of dumb IMO. Center is better!
Shep

 

[huskihl]

Can't see where that would help wear. Case of dumb IMO. Center is better!
Shep

The only reason I can think of is ease of assembly. With the ring in the intake, it can catch in the roof when they assemble it. With it on the side, it slides up between the transfer and intake

 

[mettee]

From what I always read the corners of the ring should be chamfered so they aren't sharp. When we built engines that was standard policy, couple of touches with a dull file.

 

[mettee]

Well I just picked up a 7300 Dolmar from a board member...cant wait to get it here.

 

[mettee]

Little exhaust work. I made a slit in the top, that lines up with the roof of the port and will get mig'd back together. I'm also going to close off the holes in the top so that there is flow promoted instead of the exhaust being diffused.

The lower is also matched with the floor of the port and I might also plug the first few holes in that to maintain flow.

My thinking is that the first 4-5 inches in a pipe won't have holes in it. It's usually a gentle taper, and I'm trying to mimic that with this stock muffler.

Ill take some more pics later to show it better.

 

[Wilhelm]

Little exhaust work. I made a slit in the top, that lines up with the roof of the port and will get mig'd back together. I'm also going to close off the holes in the top so that there is flow promoted instead of the exhaust being diffused.

The lower is also matched with the floor of the port and I might also plug the first few holes in that to maintain flow.

My thinking is that the first 4-5 inches in a pipe won't have holes in it. It's usually a gentle taper, and I'm trying to mimic that with this stock muffler.

Don't over think it, just let her breathe.

 

[mettee]

Trying new stuff is half the fun...

 

[mettee]

Hopefully that let's it exhaust.

 

[Deets066]

Hopefully that let's it exhaust.

That would never make its way back in one of my saws after it came out.

 

[huskyboy]

I threw the birdcage of mine in the trash, I cut off the back plate and put that back in though.

 

[Woodpecker]

Trying new stuff is half the fun...

I don't want to discourage you because you are doing a good job and having fun, but your not exactly blazing new trails here with this saw.

I threw the birdcage of mine in the trash, I cut off the back plate and put that back in though.

Me too. Everything forward of the back plate is scrap.

 

[Wilhelm]

I have kept the bird cage, but opened it up, both my PS-7300 & PS-7900 seem to like it - and I love their sound.




I removed the entire SLR thingy on my PS-7310, she has a completely different tone.

 

[Wilhelm]

PS-7310 SLR removal

 

[mettee]

That would never make its way back in one of my saws after it came out.

Okay what's your thought process on that? I'm trying to learn and try different stuff.

I'm open to leaving it out too. I can do another exhaust if I mess this up.