Dolmar 5100 S Freshen Up

[kingOFgEEEks]

Chiming in to say that I run a 68DL 18" 3/8 on my 5100, and I don't feel that it's too much bar. Only 4 more DL gets you to 72DL 20", so I wouldn't think it would make a big difference.

These are definitely a gruntier 50cc saw than a Stihl or Husky. Still have plenty of speed, though. I wouldn't consider getting rid of mine for anything. At one time, I owned a MS261 and a 550XP also, but they're both gone and the 5100 just put some firewood in the stacks last weekend.

 

[Miller Mod Saws]

I run 20”-3/8 lgx on mine as well.
Side note. She’s been tweaked a little!!

 

[NCFarmboy]

Chiming in to say that I run a 68DL 18" 3/8 on my 5100, and I don't feel that it's too much bar.4 more DL gets you to 72DL 20", so I wouldn't think it would make a big difference.

20" 72dl has 2 more cutters than 18" 68dl and you get 2" reach. I used to worry about 18" or 20" til I realized cutter count.
Shep

 

[kingOFgEEEks]

20" 72dl has 2 more cutters than 18" 68dl and you get 2" reach. I used to worry about 18" or 20" til I realized cutter count.
Shep

Perzactly.

 

[Backtroller]

The sad thing about the entire dolmar/Makita line is that besides saw geeks, they are not known of. I’ve had a bunch of people ask me what’s a Dolmar?

I had a neighbor (who I’m not fond of) rent a 6421 and complain that it was a pos since he cut as much dirt as wood and the saw was “junk”. People who run them that shouldn’t be allowed to handle anything with an engine. That doesn’t help the imagine.

 

[Dirtmagnet]

Just got back from vacation. Started tearing the saw down. I was quite wrong about it not being apart before. Someone tried to “fix” the exhaust side aluminum transfer.

Piston is junk, but I ordered an OEM from @fordf150 . It’s on its way.

The cylinder should clean up, but there are witness marks from more “fixing”


I will work on that in the next day or two. Anyone done a no base gasket build on these saws? I will check squish with the new piston, but wondering if there are any gains there.

Also, any tips on the muffler mod? Seems a bit difficult and restricted. I think I will try removing the deflector and opening up from the top.

 

[huskihl]

Should be good on the gasket delete. Just checked today. .021" at the plating is the tightest

 

[Dirtmagnet]

Should be good on the gasket delete. Just checked today. .021" at the plating is the tightest

Perfect. I will double check. Thank you sir!

 

[huskihl]

Perfect. I will double check. Thank you sir!

You'll need a tube of motoseal sealant or the like. Some kind of fuel resistant sealer. A thin layer on the case that you can't quite see through. Q tip works for application

 

[NCFarmboy]

Why BGD most 5100's blow 185+. One of mine blows 210 w/base gasket.
Shep

 

[Skisawyer]

What running conditions cause that piston transfer, and does it need cleaned up in the first place? Seems like whoever did that scratching ruined something that would have run a long time, no? Just learning here.

 

[Dirtmagnet]

You'll need a tube of motoseal sealant or the like. Some kind of fuel resistant sealer. A thin layer on the case that you can't quite see through. Q tip works for application

Yep, I use three bond 1182 on my other builds. Works great.

 

[Dirtmagnet]

Why BGD most 5100's blow 185+. One of mine blows 210 w/base gasket.
Shep

Its not necessarily just about compression increase, but also the slight timing change. If there is no real benefit, I will put the gasket in.

 

[Dirtmagnet]

Finished cleaning up the cylinder. Came out fairly well. Not perfect, but nothing in the cylinder I can catch with a finger nail. Ball hone + extensive solvent tank cleaning + a few minutes with hand soap and water and ready for assembly.

 

[NCFarmboy]

Need to clean base gasket surface more IMO. Take it easy on the ball hone Dolmar plating is thin. Also, do more cross hatch w/hone in the future.
Shep

 

[Dirtmagnet]

Need to clean base gasket surface more IMO. Take it easy on the ball hone Dolmar plating is thin. Also, do more cross hatch w/hone in the future.
Shep

The base gasket surface, although it looks bad in the picture, is completely smooth. Nothing there will catch a finger nail. It’s also clean. The cross hatch I will work on in the future, but as you already mentioned, I only honed enough to clean up the cylinder (didn’t spend much time with the hone at all) nothing more.

 

[Dirtmagnet]

Got the saw back together. Couple things I noticed that I thought were worth mentioning for anyone in the future.

1. Without base gasket, I had a head slapper. Zero squish. With the gasket in, .022”-.025”. Plenty good enough.



2. I ordered a new air filter from @fordf150 . I noticed a difference between the old one and the new one. Old one has a “nub” that looks like it lined up with the hole in the Zama carb cover. The new filter has that passage way deleted.



Anyway, that is all for now. Planning to stick it in wood this weekend. Will give a report when I get back.

Also wanted to thank everyone for their input and assistance!

 

[Dirtmagnet]

Had a chance to run the saw today. Put a tank and a half through it. Had it pig rich for the first tank. More so than even I thought. 11,500 RPM on the tach. . Second tank was tuned to 13,400 RPM. Saw ran great no matter the tune. Would idle all day, revved up great. No air leaks. Pulls the 18” 3/8 with no problem, even a nice chip from the semi chisel the saw came with. My dad was having a hard time putting it down. Picture of a tree he was working on. Damn snow is literally knee deep.