Mastermind Meets The Dolmar PS-6100

[Deleted member 83629]

i think my saws fall into that category of low speed moderate torque which is fine with me i just need a saw that will hold in the cut.
i ran a old torque monster years ago and it was awesome yes it was slow but it was gear drive and the torque the engine produced made up for the lose of speed
homelite super wiz 80.

 

[bryanr2]

Where does the Echo 600p or 620p fit into the mix with the 6100?

 

[fastLeo151]

Imo the echo saws mentioned are not anywhere the same build quality.

 

[Mastermind]

I like the 600P quite a lot myself. Like Andy has said though, the Dolmar is a well built machine.

 

[Terry Syd]

I couldn't find the size of the carburettor, but I did find that the USA model has a different High speed needle - http://download.dolmar.com/manuals/23803.pdf

 

[Mastermind]

Terry, I'll have to get into it tomorrow to see.

 

[Terry Syd]

The reason I'm wondering is I believe the 562 had a 12.5mm carb. Maybe the Dolmar carb is bigger (or smaller). Maybe the relative carb sizes might give an insight into how effective the different strato systems work. That information might then lead to a suggestion on modding.

It appears that the previous Suzuki piston port/reed system and the Dolmar system may have the same advantage, a stronger mid-range/ torque. I wonder if there are any old articles around about modding the Suzuki system.

EDIT: Found one by a former wrench for an Australian team - "We had all the nice stuff like Factory Magnesium Hubs and Fox Airshocks, Engine wise one of the tricks that works with Case Reed Suzuki engines is to double up on the reed petals and in so doing retard the reed timing and then Port the Piston Port intake area for more port timing, Believe it or not that made a nice boost to Torque."

 

[Mastermind]

The dolmar carb is much larger.

 

[bryanr2]

How do you think that 6100 would fair against my 359 and 262xp?

 

[Mastermind]

About even.

 

[fordf150]

Where does the Echo 600p or 620p fit into the mix with the 6100?

I really like the 620. They run good and are a nice saw for the money when compared to the other 60cc saws out there. Dolmar seems to have better build quality and better a/v. I Do wish the dolmar had some of the features that the echo has but at over a $100 cheaper I can't complain

 

[bryanr2]

Steven, are you considering one of these?

I'll have to try one of these out, but in a few months. I spent a little over $2k in the last month on saws and it's only March. Gotta save some for later in the year or I will have a really long dry spell of no new toys. That said... I bought me a new 241cm from Jeff which means Im only missing 2 mtron saws- 441cm, and 661cm. I have no interest in the 362cm. When I secure those two Im walking away from saws forever.

 

[jimmycrackcorn]

When I secure those two Im walking away from saws forever.

Haha.... "Just two more." says the cad addict. I think they have programs for that.. Check with your local obumma care rep, it might be covered.

 

[bryanr2]

I purchased private insurance so I dont have to fool with that "fools" solution.

 

[Deleted member 83629]

no i got obamacare and i see nothing under any form that mention CAD now back to dolmar's and other things.

 

[LegDeLimber]

The reason I'm wondering is I believe the 562 had a 12.5mm carb. Maybe the Dolmar carb is bigger (or smaller). Maybe the relative carb sizes might give an insight into how effective the different strato systems work. That information might then lead to a suggestion on modding.

It appears that the previous Suzuki piston port/reed system and the Dolmar system may have the same advantage, a stronger mid-range/ torque. I wonder if there are any old articles around about modding the Suzuki system.

I can't recall the Suzuki name but Yamaha called theirs "torque induction"
the motor was piston ported but with a reed cage betwixt the carb and cylinder.
The intake port had an upper cutaway that served as another transfer port.
The piston had a couple of holes in the intake side of the skirt to allow
so that on the down stroke a back flow of fuel/air through the holes
which then passed through the intake port area up through that boost port
cutaway into the combustion chamber.
a bit of hole size reshaping ( sorta like matching muffler opening to cylinder) and maybe 1 or 2 more smaller ones would do interesting things to the midrange grunt of a the yamahammers.
the reeds did cost a bit of top end revs but it made for a much more enjoyable/usable powerband in the woods.
Plus they tolerated a bit of "over-carburetion" better, due to the reeds.
It did make one a bit sloppy to throttle then though.

I'll give ya One guess what brand I liked, rode and owned more of.

 

[Terry Syd]

Yamaha's 'Torque Induction' was the boost bottle on the intake. It changed the resonance in the intake tract and gave a nice bit of torque down lower in the band. The Suzuki system was referred to as a 'Power Reed'.

That reference I found to modifying the system on the Suzuki talked about increasing the intake duration and doubling up on the reeds. Allegedly this doubling up was to "retard the reed timing". I figure the wrench just made that up because it sounded plausible, not that it was accurate.

Reeds can be tricky things, the flow characteristics on various reed constructions and thickness varies all over the place. Generally, a thicker reed flows better at high speed and thinner at low speed. Thus, you see something like the Boysen reeds where a thick reed with windows has a light reed on top of it. Essentially, they are trying to get the benefits of both types of reeds.

I figure the doubling up may have dampened some flutter at a certain rpm which improved the power characteristics.

 

[LegDeLimber]

My stuff then was all early to mid 70's vintage. Never got to mess with the boost bottles (puberty sorta drew me aside by then)
the yamahas metal reeds would hum if you eased the engine over slowly.
Can't personally recall hearing any of the fiberglass one on other brands doing it.

I remember the magazine articals about the layered or tapered reeds.
aside from restriction and flow rates, the most commonly mentioned theory
about the taper was to regard it like a super long triangle and thus having no inherent resonant frequency.
Think like a short fishing rod or some old type car aerials.
and if you want some reeds, here's a few for ya.(PB-500 Echo)
the twin petal feeds the crankcase from the carb and the single petals on the plumbing are the transfer caps and feed from the strato valve.

 

[Treespotter]

Randy, I asked you about the air 'pressure' under the air filter cover a couple of days ago. I think I found the answer!
I drilled a couple of holes in the cover right in front of the rear handle bar.
It's an overstatement to say my hand froze off, but there was quite a storm flying over my hand.
Closed the holes again with some duct tape from the inside.

Wolter

 

[nmurph]

What's the compression post-port? It was pretty strong stock. Was the machining more to get the numbers where you wanted (I know you wanted to raise compression some)?