2159 new AM cyl 100psi

[davidwyby]

This muffler still needs to be Swiss cheesed...tomorrow. Unfortunately I don’t have a good before vid, but I’m gonna stick it in that same super hard, dense log it couldn’t cut the other day.

 

[davidwyby]

Also advanced timing roughly a few.

 

[davidwyby]

Made a few cuts, runs a lot better. 4strokes at 12k RPM. Seems to have a low, torquey power band. More after a while. Cold and hungry, going home for some warm grub.

 

[davidwyby]

I don’t have much frame of reference for a 60cc saw but it’s defintely better. No Timberwolf saw, but grunty. It will be interesting to compare to the 357 top end when it gets here. Then I’ll have a reference.

I put the 20” bar and 3/8” husky chain with "flop ear" rakers from the 2255 project on it to get away from the rough cutting Forester chain. Wasn’t sharp, wasn’t dull. Forgot file at home. Ate up the super hard log it couldn’t cut before. Buried it in the dry, hard pine too. Seems to have a lot of low end grunt, yanks into the wood hard if I don’t dog it. I noticed I could lean on it so hard without stalling that I was overpowering the antivibe and my knuckles were hitting the brake. Kinda that low rpm torquey feel of my 49SP.

Compression went up a couple psi after a little less than a tank of tuning and cutting. I think it’s still not broken in.

Pics of spark plug from a few days ago and one tonight after cutting. In the one from today, it is oriented in the pic as it is in the saw. Looks like maybe it’s rich and washing off the intake side? Maybe rich with spitback because the intake is low? I dunno. As I mentioned, it will run up to about 13,700, but doesn’t 4 stroke til all the way down at 12,000. Thoughts? Almost vac tested it, probably should.

I did a temp fix on the intake boot and throttle rod until new ones get here. After I got done, I noticed the throttle rod must have compressed again a bit because it wasn’t opening the carb all the way. Just a hair short.

Muffler - I drilled a couple 11/16" holes in the middle of the baffle thru the inlet port. There was already one low to the side. Also drilled two for outlets thru the case and the baffle, so it’s pretty well Swiss cheese. Welded pipes in with .035” hard wire, should have waited to have one of my good guys tig it in.

All in all, I’m happy. At least it’s useful now.

@MAF143

 

[Marshy]

Yep, your rich.

 

[davidwyby]

After talking to @Benwa, I think I’ve built a tractor saw. I think the intake and exh durations are upside down and this is why it 4strokes so low and the plug is “washing”. Not enough exh flow, intake charge is stalling.

In duration is 164* and exh is 156*. Blowdown 18*.

What do y’all think about raising exh port more to even out the duration numbers? Less trouble than raising intake and I don’t have small enough tooling to get in the upper transfers. If I did, what would I want to do?

Thanks

 

[Marshy]

Just turn your high jet in and it will lean out some. I'd run it more with a leaner tune before going back into it but that's just me. You are leaving a lot on the table with just a simple carb adjustment.

 

[davidwyby]

I had the tach out and tuned it. If I lean it, it will run up to 13,7, but have to richen to get it to 4 stroke and it doesn’t 4 stroke until all the way down at 12k.

 

[Marshy]

The plug color at 13,7 is nor important than hearing an audible 4 stroke.

 

[davidwyby]

That’s sort of a back to the drawing board for me. I was under the impression that if it wasn’t 4stroking, it was too lean.

EDIT: Also, that port timing change was what changed where it would 4 stroke, and the 4 stroke is the saw "telling" you where it wants the carb H set.

Maybe I can lean it and tune it by the plug. I’ll post a video later but another thing I just remembered is that before I richened it, after a cut or hard rev, it would clatter for a sec afterward. Couldn’t tell what it was, makes me nervous...lean knock?

 

[Marshy]

Clatter? Get video?

 

[davidwyby]

Sounds like my 49SP

 

[Marshy]

At idle some yes. Probably the muff mod.

 

[davidwyby]

At idle some yes. Probably the muff mod.

Why would it do it only after rev/load and then go away?

 

[davidwyby]

Got some spare plugs tonight and sharpened the chain with a husky roller sharpener. Rakers were way high, still pretty high. Raker guide doesn’t work well on the flop eared rakers. I have a good chain coming but for now it’s either this 20” husky chain or the 18” Forester that was on it.

Gonna test and tune tomorrow at lunch and after work. If no 4-stroke, how does one make sure not to go too lean? Find max RPM and then drop it a couple/few hundred and tune with the plug from there?

Thanks gents.

 

[Benwa]

I kind of hear the "clatter" maybe just the clutch/drum? Hard for me to tell. Best way to tune is in the wood. hard for me to discern 4 stroking in the video you posted, I may be hard of hearing. Get it where you think it's 4 stroking no load. Even if at 12k. Hold it wide open throttle (4 stroking), now put it in the wood, did the sound change "clean up" with load put on it in the wood? (Don't read this as "a lot of force down on the saw" just a little pressure and the load of the chain cutting wood itself is enough). If the saw sounded the same (4 stroking) in the cut as out of the cut you're too rich. Lean it out a bit and retest. I'll do this multiple times in a cut. Pressure(clean sounding), then lift slightly and listen for 4 stroke, pressure again and listen for it to clean up. You want 4 stroke out of the cut, then clean up/crisp 2 stroke sound in the wood. If this is all repetitive ,no S%*t Sherlock, info for you I apologize in advance. I May have misunderstood the question in the prior post.

 

[davidwyby]

More test and tune at lunch and after work today. @Benwa pointed out that if it’s running at a lower RPM than stock due to lower ports, perhaps advancing the timing wasn’t such a good idea. Bingo. Got it 4 stroking at 12,500. Seems to run pretty good. Plug is a new one after several 19-20” diameter cuts with minimal idling.

Perhaps if I went and raised the exh roof, I would gain more top end....? Honestly though, I’m pretty happy with making it run decent.


ALSO, my box of goodies showed up from @Spike60 sooner than expected, thank you sir! Now I have a ton of work to do. 357 top end, bearings, seals. More of the same on the 395. Can’t wait to get it back together and blow through some big chunks with the 24” and some full comp.

 

[jasper89]

I am interested in hearing what you think of the 357 top end and how it compares to the 359.

 

[davidwyby]

I am interested in hearing what you think of the 357 top end and how it compares to the 359.

My cheap, messed with 359 isn’t a very good measuring stick but I will for sure post up.

I know I’ve read a bunch of different posts about it, but can’t remember the consensus : what do you guys think about running the 357 top without stuffers? Maybe I should get some while it’s apart.

 

[davidwyby]

Did I say something wrong? Y'all don't like Californians? We're not all the same, you know... ;-)