the all aussie dribble thread!

[masculator]

OK guys so is there a saw that you have used in your years of sawing that really stands out as not necessarily your favourite but most memorable or adored?

Personally mine is my 034 for reasons you may learn one day!

 

[masculator]

I stuck two of your bits old buddy and yes, you Aussies are fine gentlemen.

Shovel this place out when you-all leave.:hmm3grin2orange:

I had noticed and even if the others don't shovel I will buddy! wish you could come to the GTG!

 

[Stihlman441]

yeah go the 880 best saw ever built, reliable,powerfull , well built, excellent all round design simply the best

Sarcasm is a good thing i use it on the misses all the time.

 

[porky616]

Sarcasm is a good thing i use it on the misses all the time.

:hmm3grin2orange: its hard to type sarcasm, glad you picked it up andrew

 

[AUSSIE1]

OK guys so is there a saw that you have used in your years of sawing that really stands out as not necessarily your favourite but most memorable or adored?

Personally mine is my 034 for reasons you may learn one day!

My 371XP was my first Husky 13-14 yrs ago and my second saw after an Echo 750VL and will probably be my only saw in time.

It's gone through a few transitions over time with the fitment of a big bore kit and various stages and configurations of porting, a brilliant allrounder.

 

[Rudolf73]

Looks like new Al, sweet! I would like to try a real 365/372 frame husky someday - I don't think the chinese one I have does the model justice.

 

[Nardoo]

OK guys so is there a saw that you have used in your years of sawing that really stands out as not necessarily your favourite but most memorable or adored?

Personally mine is my 034 for reasons you may learn one day!

This 084 was my primary saw for about 13 years. It cut an awful lot of dry boxwood for me and never let me down once. These days it is a bit heavy for my back and I use lighter saws of a variety of brands, but I still have a soft spot for the old girl.

Al.

 

[Terry Syd]

I know Matt has a tach on one of his saws, I was wondering if anyone else did and could check something for me.

I was wondering how tweeking the High Speed needle affected the power in the cut.

For example, does adding just a tad more fuel allow the saw to pull better at a bit lower revs, and if so, by how much (with the tach you can eliminate subjective impressions).

The reason I ask is that I am still not comfortable with my knowledge of these diaphragm carbs and how to tweak them to get a bit better metering.

I keep going back to EC Birt's webpage and trying to find some tuning principles, but all find is some specific advice about changing the pop of pressure (sometimes just a half lb) and/or changing the metering lever height. - Further, I have never seen a thread on this site that addresses changing the metering capabilities of the carb.

 

[masculator]

I know Matt has a tach on one of his saws, I was wondering if anyone else did and could check something for me.

I was wondering how tweeking the High Speed needle affected the power in the cut.

For example, does adding just a tad more fuel allow the saw to pull better at a bit lower revs, and if so, by how much (with the tach you can eliminate subjective impressions).

The reason I ask is that I am still not comfortable with my knowledge of these diaphragm carbs and how to tweak them to get a bit better metering.

I keep going back to EC Birt's webpage and trying to find some tuning principles, but all find is some specific advice about changing the pop of pressure (sometimes just a half lb) and/or changing the metering lever height. - Further, I have never seen a thread on this site that addresses changing the metering capabilities of the carb.

I do not believe it does! Their is a point where the amount of air incorporated with the fuel charge is too much (lean) and also where it is too little (rich), the secret is finding the happy medium between these points. generally this is where you get four stroking at WOT and clean 2 stroking under load. When I am milling with my chainsaw I try to run a little on the rich side of this point but not because it gives more torque, more to allow it to run cooler for the longer periods where it is at WOT I get more torque running leaner like when I set it up for crosscutting, to a point, it will then drop off and you know you are running majorly lean.

best way to find out is arm yourself with a screwdriver and make some adjustments when you are cutting but just remember a small change to the screws can make a big difference to performance so just make minor amounts of adjustment and evaluate what has happened each time you do. Another thing to remember is the leaner a motor is the hotter it runs, and the lower the octane rating of your fuel the hotter it will run!

 

[tdi-rick]

[snip]
I keep going back to EC Birt's webpage and trying to find some tuning principles, but all find is some specific advice about changing the pop of pressure (sometimes just a half lb) and/or changing the metering lever height. - Further, I have never seen a thread on this site that addresses changing the metering capabilities of the carb.

Terry, I always go back to Tillotson's advice on pop off pressure.

If it's too low the carb will be too fat coming off corners (accelerating) and if the pop off is too high it will lean out at high revs, generally characterised by not cutting off cleanly when lifting off the throttle at full revs.

Zama and Walbro specifically state not to pop off the carby, just check that it holds pressure for 30 seconds or so, they claim it may stretch the diaphragm but it was something that was considered pretty critical when I raced 100 years ago.

I seem to recall opening up the metering chamber with a die grinder too to ensure a greater volume of available fuel, then adjusting the lever height to suit. (Tillo HL)

This was the generic advice for the old HL carbies, but it applies to any diaphragm carburettor.

Track tuning your Tillotson Carburetor.
If the carburetor settings are too rich ( too much fuel ) the engine will falter at that section of the track corresponding to that particular range of the carburetor settings. A spluttering or irregular firing sound will be heard. This sound is also called 4 stroking. If this sound occurs at low speed while at full throttle, such as coming out of a tight turn, it is usually due to the Low Speed adjusting needle being turned out too far. If the sound occurs at high speed while at full throttle, such as on a straightaway section of the track, it is due to the High Speed adjusting needle being out too far. In either case, needle adjustments must be made inwards gradually, in approximately 1/8 turn increments. It is best to adjust the Low Speed needle first for best overall low speed performance and then follow with the final high speed adjustment.

If the engine does not 4 stroke or give the too rich firing sound, any place on the track, it could be because the engine is running too lean ( not enough fuel ). This is easily checked by opening the needles out in 1/8 turn increments until the engine 4 strokes. In general, the optimum performance and engine reliability will occur at carburetor settings just slightly leaner than the point where the engine will begin to 4 stroke.

If you find that the engine will not chop off clean or is slow to come back from high rpm's when you lift the throttle, this is a sign that the pop-off pressure in the carb is too high. The cure for this is to lower the pop-off pressure. If you experience loading-up problems, this is a sign that the pop-off pressure may be too low. The cure for this is to raise the pop-off pressure. As a general rule of thumb, the pop-off pressure will be from 8 to 12 lbs, and is a tuning factor that you can adjust for the altitude of your racetrack and the type of racing that you do.

 

[masculator]

A tacho would not really give you the answer to the question either, the only true way to measure if it did or not would be to use a dynamometer and take measurements of torque, revs, and horsepower. A tacho only tells you what revs you are pulling, and the true power ratings would be sheer speculation. Then other things come into play such as air pressure, altitude, moisture content of the air etc. and honestly what you tuned it on the dyno at on a wet day at 50 metres above sea level would be completely different to what would be the optimum at 300 metres above sea level on a dry sunny day. Really you need to learn how the adjustments on your carby effect performance and learn what you need to do in different circumstances. I.E. at 1000 metres above sea level you may have to lean your saw by as much as 1/4 of a turn on the H screw but at true sea level you may have to richen it by as much. this is because at higher altitude the atmospheric air pressure is lower than what it is at sea level or in laymans terms there is less oxygen to use in the combustion cycle.

 

[tdi-rick]

[snip]

just remember a small change to the screws can make a big difference to performance so just make minor amounts of adjustment and evaluate what has happened each time you do.
[snip]

The Tillo advice I posted above says 1/8 turns, but I was taught and always use 1/16 when fine tuning.

That probably comes from running so close to the edge, which is why back in the day we used to choke the air cooled kart engines at the end of the straight, just to give them a gulp of raw fuel to keep them cool.
On a rotary valved engine back then, it was a touch risky as your carby is right above the drive sprocket and chain, just ask Russell Ingall, he's missing the top off his (middle ?) finger.

 

[tdi-rick]

And this is for Trav and Andrew.

Unfortunately it won't work on Randy, he's already seen it and guessed what I had in mind

It's courtesy of our current Australian Open Chainsaw Champion (overall pointscore)

Cheers lumberjackau !

 

[husq2100]

I think Terry's idea of using a tach, is not to measure power....as we no it wont...but to see a specific rpm with regards to the tune adjustment so as to have a referrence when then timing in the wood.... I know some guys that use timing in the wood to tune...IE get a nice consistant log of equal dia, make 3-5 cuts at one tune, timing each, then adjust and redo...take your fastest time....a bad cut from wood or operator will throw out averages....This in conjunction with plug colour may be a good way to do it....

I have very little experience tuning and just use a tach and manual to set on my stock saws....I dont trust my ears

 

[porky616]

picked up an old 088 today. its been through hell, missing cylinder muffler top handle and top plastics and couple of little things but for the sum of $5 i think it will make a good project

 

[tdi-rick]

picked up an old 088 today. its been through hell, missing cylinder muffler top handle and top plastics and couple of little things but for the sum of $5 i think it will make a good project

I have an 084 cylinder that's my practice jug.

So I just need the rest of a saw for a good project/post rip saw

 

[Terry Syd]

Forgive me for being an obsessive tuner, but the carb issue on work saws is still bugging me - and after reading all the tricks on EC Birts forum, I feel there has to be more in it for a work saw.

The analogy I make is that a race saw is set up for the sweet spot in porting - kind of like setting up a dragster. Whereas a work saw is more like setting up the jetting on an enduro bike.

When you are cookie cutting, you try and keep the saw in the sweet spot - it seems that almost any carb can be set up to work within that narrow range. I've seen some bored out carbs for racers that I know would never meter well on a work saw.

However, the varying conditions of a work saw demand a broader range of good metering (like the enduro bike). I noticed the last time I was cutting that if I opened up the high speed needle another 1/8 turn that it seemed like I could pull the saw down below peak torque and not have as great a problem with bogging. I also noticed that it knocked some power off my peak horsepower.

All this is largely a subjective feel. If I had a tach installed on the saw I would be able to monitor and document the rpm levels to confirm the spread of power and where it bogged.

I just may have to get a tach to mount on the saw and a pop off guage (and a bunch of springs and shims). I could start out with one high speed setting on a log and document where the power was, then tweak it a bit and see how that changed the spread of power. Then, try a different pop off pressure and re-test.

My gut feeling is that a slight drop in pop off pressure along with a slight leaning of the high speed needle would give me broader and more forgiving powerband - just what I want for a work saw.

Matt, do you have any more of those tachs?

 

[husq2100]

Terry, are you referring to "modded" work saws?? as I imagine Husky/Stihl/Domar/Solo etc etc etc would already be using carbs designed for the work variables when they engineer there saws...

 

[Terry Syd]

Yep, I'm referring to modded work saws. Some of the guys are doing a considerable amount of 're-engineering' to their saws with different pistons, pop ups, milling of bases, different timing and area of the ports, muffler mods, bigger carbs - but I have yet to see one builder discuss changing the pop off pressure of the carb they are using.

Try to think of one thread where pop off pressures were discussed.

Now go to a kart forum and see how many threads are devoted to changing the pop off pressure or the height of the metering lever.

Rick, good idea on enlarging the metering chamber to give it more volume. I had read about decreasing the distance of the metering lever to the diaphragm to give the carb more volume, but grinding the metering chamber out a tad sounds like a more reasonable starting point for increasing volume.

 

[husq2100]

I have an 084 cylinder that's my practice jug.

So I just need the rest of a saw for a good project/post rip saw

I keep telling you to get the bloody thing.....if that 084 is still available to you at a good price you sould pull the trigger....one of stihls better saws, and better from what ive read than the 088/880...............