Mastermind Meets The J'Red 2188

[mdavlee]

I like the Tilly on them better personally.

 

[Jacob J.]

I like the Tilly on them better personally.

My feeling is that over the long haul the Tillotson is the better carb. The newer, larger Walbros are very sensitive to ethanol containing fuels and the diaphragms get eaten up fast.

But when they're new, the Walbros make a good running saw.

 

[bcaarms]

Finally got to run the 2188 Terry did for me in some big wood. Actually had the 36" buried in a split Oak that got blown over during the tornado a month ago. The root ball is going to be a mess to deal with. Had to sharpen the chain three times. The hollow part of the split tree is very dirty and really eats a chain quickly. Learning to allow the saw to cut at its pace with the 36, it screams with a 24". Oiler seems to be less than 385xp, but might be my memory, not sure. By myself so pic with me in it is too much trouble in 90 degree heat.
The showing cut is about 32".

 

[Mastermind]

Porting 101 question....

How do you determine when a saw has too much exhaust duration? Is it all in the timing numbers, do you calculate port areas as well? Or is this something that can be determined from the way a saw behaves? What are the "symptoms" of a saw with excessive exhaust port time area?
My questions are from the point of view of a saw that hasn't been developed over multiple port jobs.
I'm not discounting the role experience plays, just trying to get my head around it. I can see how exhaust port height effects the power band, just unsure what occurs when exhaust port area is excessive.

To be honest.......it's just from experience with these models, and trying different things that I've built the spec sheets I use for each model.

 

[bryanr2]

Thread should have been labeled "Mastermind meets the Sexiest Saw on the Planet"..... You gotta own a Jonsered to understand it.

 

[Homelite410]

Thread should have been labeled "Mastermind meets the Sexiest Saw on the Planet"..... You gotta own a Jonsered to understand it.

Yup, you said it right there! Maybe someday one of my Jonsered saws will make it down there! 2145 maybe.....

 

[SawTroll]

I like the Tilly on them better personally.

The Tilly carbs speced for them aren't any larger as far as I know (both have about a 17.5 mm venturi) - but that is of course not the only way a carb can be better.
However, I suspect a larger carb is somewhat underrated on these pages - I know it makes a big difference on the 385, and even on smaller saws, so why not on the 390?

Of course it is some extra work to fit a larger carb, as none of them fits as is (that I know) - and of course more cost - so the total price of the work would go up quite a bit.

 

[jeff taswelder]

Nice work
u da man

 

[mdavlee]

The Tilly carbs speced for them aren't any larger as far as I know (both have about a 17.5 mm venturi) - but that is of course not the only way a carb can be better.
However, I suspect a larger carb is somewhat underrated on these pages - I know it makes a big difference on the 385, and even on smaller saws, so why not on the 390?

Of course it is some extra work to fit a larger carb, as none of them fits as is (that I know) - and of course more cost - so the total price of the work would go up quite a bit.

It just seems some of the saws I've run side by side the tilly version had better throttle response even when tuned the same and all. Not sure why. I do have one for an 084. Wonder if that would fit under the hood of the 385?

 

[SawTroll]

It just seems some of the saws I've run side by side the tilly version had better throttle response even when tuned the same and all. Not sure why. I do have one for an 084. Wonder if that would fit under the hood of the 385?

Well, I know you can put a 395xp top end on a 056mag (it takes a lot of work, and spacers, etc - but is doable) - but I never before heard about anyone being interested in putting a Stihl top end on a Husky saw (usually counter-productive).

If that project is possible, I want to hear more about it though, as the cc difference is so large......

 

[mdavlee]

Well, I know you can put a 395xp top end on a 056mag (it takes a lot of work, and spacers, etc - but is doable) - but I never before heard about anyone being interested in putting a Stihl top end on a Husky saw (usually counter-productive).

If that project is possible, I want to hear more about it though, as the cc difference is so large......

I was talking carb only. A husky bottom end wouldn't last 3 cuts under that pressure.

 

[SawTroll]

I was talking carb only. A husky bottom end wouldn't last 3 cuts under that pressure.

That sounds more like it!

 

[SawTroll]

Excuse me for my maybe simplified theory - but I believe the carb/intake, the transfer capasity, and the exaust need to match, to form the baseline for further improvements, like the flow pattern in the cylinder.

Bettering a single factor doesn't always help a lot, unless it was a weak point to start with.

 

[mdavlee]

It depends on how wild the porting is. I've got the carb laying around and one without a choke butterfly on my 088 right now. I wish there was a 19-20mm venturi carb easily available to swap.

 

[blsnelling]

Sawtroll, why do you always insist that the carb is such a bottle neck on these? Sure, they can benefit from a larger carb, but no different than most any other saw. They run fantastic with a stock carb.

 

[SawTroll]

Sawtroll, why do you always insist that the carb is such a bottle neck on these? Sure, they can benefit from a larger carb, but no different than most any other saw. They run fantastic with a stock carb.

Just the obvious reasons, like they are larger than the 67cc saws from the 1980s, that needed a 17.5 mm venturi - a bit of common sense - and someone that actually put a larger one (19 mm +) on an unported 2186 to check. It reportedly made a huge differense. That saw did of course have a more open muffler as well, but Zero port work.

 

[Mastermind]

The XT carb is larger, and works very well on these.......but it's not a huge improvement.

 

[blsnelling]

A ported 390 makes a lot more power than a MMd one, and will do so with a stock carb. I'm just trying stop the creation of a false notion that a bigger carb is required to build a very strong 390XP. This is not based on a sample size of one, done by someone else either.

 

[Mastermind]

I agree completely Brad. I see no reason at all to swap carbs on these.

If I was building a race saw.......well..... I don't build toys.....so forget that.

 

[SierraWoodsman]

Looks like you changed up the way your doing the MM's on these a little.
Any reasons for not adding the port out the front on this muffler?
Just Curious