More bad luck

[Andrew96]

I believe TW merely used a pencil & paper port map to determine timing, not a degree wheel, though I could be wrong. Point being, a paper map is only approximate so you would expect a little variation from one person's map to the next.

Are you saying your 660 has even more exhaust duration that TW's ? How's your compression ?

I didn't think he used a wheel either. I measured things up a bit..then did a quick TDC and ex duration. I don't have my book here but I do remember it was 'around' 5deg longer duration (somewhere near 180!). TWs duration was high for such an oversquare engine...mine was higher. I had expected to see peak HP at 11-12 k with that but that isn't so. The objective was to inspect and measure for wear and get milling! so I didn't do a full work up. I still get 150 and 155wet compression. Not high but that's my baseline. I 'feel', my cylinder isn't the same as the one he was working over, it wasn't close enough to his one that I felt I was looking at measurement variations.

Regarding the BB, Baileys has no engineering staff, and it's getting painfully obvious.that they are in over their heads. I wish them the best of luck, but I suspect they will eventually accept their limitations and retreat to more modest projects.

For example, instead of continuing to struggle with the 066 BB, it might be easier for them to make a carbon copy of a pre-emissions 066 jug. No engineering required, and there definitely would be a market for such a thing.

It's too bad really. 2 stroke technology, I feel, reached it's zenith 20 years ago. There is a lot of knowledge sitting around not be used. That's one type of fun work I have had...recasting old assemblies....better. You don't make much doing it. They could have found someone to help if they wanted. However, a carbon copy with a bigger bore isn't the correct answer either. I'm sure it would have worked better than what they chose to do but leave the door open for guys like TW to make money. Clearly they didn't pass out prototypes to the right people.

Speaking of which, I've been searching old threads for a port map of a pre-emissions cylinder, but haven't found one yet. Just anecdotal comments by Jacob and Lakeside to the effect that the old cylinders had more compression and less exhaust duration.

Hmmmmm..... there have been changes to flywheels and coils, but I not sure about the timing numbers. Either Jacob or 04Ultra should be able to tell you, though.

I hope you are searching all over the web...I bet you are. I'd certainly be interested in seeing an old style map. I suspect you are 'just' going to find a longer swept volume since there isn't much left on the table here. But I'd love to see it.

Retarding timing is just another trick for lower emissions. It seems if they reduced compression, they may have retarded ignition too. I don't see any posts around with guys pushing timing.

 

[huskyhank]

snipped.....

Retarding timing is just another trick for lower emissions. It seems if they reduced compression, they may have retarded ignition too. I don't see any posts around with guys pushing timing.

They're doing it, just not telling about it much. Its usually mentioned in passing.

 

[mtngun]

However, a carbon copy with a bigger bore isn't the correct answer either.

I meant a carbon copy with 54mm bore. The 56mm bore creates all kinds of design headaches and fails to produce more power. Life would be simpler if they stuck with the original bore size.

Clearly they didn't pass out prototypes to the right people.

It is tempting to blame the field testers. Certainly Brad Snelling has been a lightning rod for criticism lately.

I would like to see some things done differently on these product tests, things like cc'ing the chamber and mapping the ports, similar to TW's 460/660 write up.

And timed cuts milling a cant, instead of merely cutting cookies. A peaky, high rpm saw may excel at cutting cookies yet suck at milling. A milling saw should have a broader power band with grunt.

But, the bottom line is that it's the manufacturer's responsibility, and some of the design flaws that have been pointed out are not rocket science. Bailey's just doesn't have the technical staff to do design.

 

[Kicker_92]

It's Alive!!!

The 385xp now looks like an almost new saw again! Finished cleaning everthing up and reassembled the fully stripped down case with all clean parts with grease and locktite where needed.

Fired it up today, and it runs like a champ. Nice burble at wide open throttle, and pulls hard in the cut. Just knocked off a couple 30" cookies to test it out, will be back to milling duty next week.

So temping to do some work on that cylinder while it was out, but after the glitches on the MS880, figured it's best just left alone.

 

[MR4WD]

Awesome; Where did you get the bottom end? I know it would be nice to have a ported mill saw, but I think it's best to fight the urge. Clearly you're blowing up bottom ends on stock saws anyways! It might be worth it to open up the exhaust while it was apart, a saw can never run too cool in the cut!

 

[mtngun]

Fired it up today, and it runs like a champ. Nice burble at wide open throttle, and pulls hard in the cut.

Good work, Kicker. :rockn:

 

[Kicker_92]

I know it would be nice to have a ported mill saw, but I think it's best to fight the urge.

A week ago I would have agreed, but not after running that saw today... Very happy with it.

It pulls much stronger now, and will happily cruise along at 9,500rpm in the cut with very low rakers.

It was a lot of work to get to this point, but really came down to finding the problem that caused the 880 to go lean before, which melted the piston. Ended up coming down to a carb kit and new fuel filter.

With milling, the saw pretty much allways stays on it's side. There is much less room for crud to accumulate in the gas tank away from the fuel filter. I'd recommed checking / changing fuel filters a bit mroe often on a milling saw now.

 

[mtngun]

It was a lot of work to get to this point, but really came down to finding the problem that caused the 880 to go lean before, which melted the piston. Ended up coming down to a carb kit and new fuel filter.

Kicker, are you saying the 880's surge is fixed, and it was either the fuel filter and/or carb kit ?

Good on you for figuring it out.

 

[BobL]

With milling, the saw pretty much allways stays on it's side. There is much less room for crud to accumulate in the gas tank away from the fuel filter. I'd recommed checking / changing fuel filters a bit mroe often on a milling saw now.

Every few months I dump and rinse out the mix tank on my saws with fresh gas. It's quite instructive to dump the fuel into a transparent container and see how much crud ends up getting into the mix tank.

Another thing I observe is a number of operators, including myself, forgetting to put the cap back on the mix can.

 

[Kicker_92]

Kicker, are you saying the 880's surge is fixed, and it was either the fuel filter and/or carb kit ?

Yes, and now it runs great with the high set to around 1 turn out, and a 10% larger jet drilled out. Tuned it to just under the 11,500 rpm limit, and it four strokes as soon as you let pressure off in the cut, but clears up nice when the chain meets the wood.

I think a big source of crud on the MS880 was refueling during a long cut. With all that sawdust floating around, I'm sure a lot drifted in.

Nice to have both saws up and running again, we chunked out a 14ft x 28" fir into some beams today, I'm happy with the way the 880 turned out even after the long troubleshooting.


Thank for everyones help on this one!

 

[mtngun]

we chunked out a 14ft x 28" fir into some beams today

But ....... where's the pictures ?

 

[huskyhank]

But ....... where's the pictures ?

No pictures = didn't happen.


:biggrinbounce2::biggrinbounce2::biggrinbounce2:

 

[Kicker_92]

No pictures this weekend, but here a shot of a differant log the 880 was working on:

 

[huskyhank]

Cool!
I've never cut anything near that long.

What are the chains for on your log pile?

 

[BobL]

No pictures this weekend, but here a shot of a differant log the 880 was working on:

Great shot!

Do you have any problems with the exhaust bouncing off such a big flat surface on the side of the cant?

 

[MR4WD]

No pictures this weekend, but here a shot of a differant log the 880 was working on:
]

Nice! What are you using for top rails? Doing any milling during the week? I'll be in the lower mainland for the next week or two. PM me if you're milling any beams!

 

[Brmorgan]

No pictures this weekend, but here a shot of a differant log the 880 was working on:

Nice! I have to cut a 26' 6X12 out of a Fir log that's out behind my place here pretty soon. I'm putting it across the back of the truck shop so I can build an upper level for storage back there.