Piston Skirt

So far from my experience both Yamabiko (Oppama/Echo/Husqvarna) and Stihl tachos were accurate. Stihl one has smaller digits and seems to refresh screen data quicker though Oppama ones refresh a tad slower but this together with bigger digits makes it a bit easier to read. Using it is dead simple - just place it near spark plug main lead.

This skill and tools would always get you the maximum power and reliability. From my personal experience - being in the forest without those tools feels a bit like driving on a long trip without spare wheel/foam kit with regular tyres

It makes no sense to compare old saws to the new ones. Modern engines (ECII emission standard) burn nearly all fuel mix while old ones threw around 30% straight to exhaust. Those 30% did quite a bit of engine cooling and the engines were way less sensitive to all factors including oxygen amounts in the same volume of air. Needless to say ~27°C of temperature difference at the very same spot (mild climate summer/winter) means ~10% lean/rich mixture difference. There are only two ways to solve it - either periodically re-adjust the carb manually or slap on autotuning device. Both ways have their advantages and disadvantages but both are inevitable for full power and reliability.

Out of question as all of the equipment must be re-tuned by dealers. Factory setting is perfectly set for pure petrol but manufacturer mandates re-tuning in ethanol-rich-and-varying-EU.

Sad to hear. Obviously it's hard to tell but in many cases mechanics might skip some steps in tuning. One of those is 20s delay between needle turns (where every mechanic I ever met was rushing and barelly gave 5-10) Anyway, drop me a PM if you got the adjustment tool.

Small engines (especially EC II compliant) tend to be a bit more sensitive to proper tuning, especially L/T ratio. 2510/2511 have completely the same engine. ECHOes have a very precise tuning procedure so if tuned properly there aren't running issues. If tuned "by ear" it is very typical to find that the unit was either running rich + open throttle or lean + closed throttle. In both occasions it has unstable idle. That's why it's recommended to have it tuned by a properly trained technician.

Yes it is, in certain markets. 501SXH is the name. http://www.echotools.com/products/category_detail/id=8861 We got them in Baltics.

I'd use starter rope as a piston stop instead of actual piston stop. It's much safer. And if there's a need just to oil the bearing you can do it through the center hole in the crankshaft without taking the clutch off. And regarding the "clumsyness" of this construction - e-clips are not reusable in most cases whereas the nut can be retightened many times and you don't need anything to do that - just pull a starter rope and use the standard T-tool. Not as clumsy as an outboard clutch

You're welcome. Anyway, have the carburetor re-adjusted as it might have been adjusted with previous airleaks present. If it is sealed now - the mixture ratio might be incorrect. For simple inspection you might check the spark plug - it should be grey/tan. If it's white'ish - it was running lean.

If your chainsaw was ever disassembled outside the factory, there is a big chance it is incorrectly installed circular washer #33. It has to be inserted into the rubber boot #31 and keep it in place. It also ensures better carburettor/boot sealing. Especially when the handle is moving on suspension in relation to engine. The fact it's outside means that at certain point of time the carburettor was (or is) loosely contacting the boot (did the chainsaw ever fall? ). Could lead to airleaks/erratic engine behavior or lean seizure.

The alternative flocked filter = the one from CS-490ES/500ES. They're fully interchangeable. And yes, the flocked ones are nearly 4 times as dense, so helps a lot in dusty/dry conditions but isn't such fun to clean especially if maintenance is not done often. The original nylon version is better to be kept clean (same could be said about any filter of any engine ) - It's generally a filter's nature. When the bigger part of the filter area gets clogged the increased vacuum starts sucking the tiniest particles in. Some of them are caught on a spitback oil film in the carb while the rest take the piston gloss away and form specific carbon deposits where you don't want it

Just out of curiosity I'd like to know where they are? Over so many years I've met quite a number of Shin/446/452s, ECHO CS-500/490/501SX consumer and forestry users (including very critically mooded husky and stihl dealers). They had number of (contradicting) opinions about exhaust direction or chainsaw being too compact lenghtwise (!) but none of them has ever pointed that sharp edge on that case. Where is it?

Funny Thing is, CS-501SX is actually lighter than 550XP. The only two measurable parameters that can actually be obvious are max. declared power (=torque at high speeds) and no load acceleration, which comes from AT/regular Walbro with no accelerator pump differences. Using the approach of very nordic husky fan I can tell "I've seen some serious tests that obviously show 501SX has nearly 10% higher torque traditionally peaking lower and thus giving way broader powerband" but sayin that is equally useless - actual usage tells more as soon as operator gets used to the saw's specifics. What actually counts in 501SX is the hard-coated piston and two-piece crankshaft that tecnically is way more advanced and reliable than three-piece/bare aluminium. Oh and PA6-GF plastic is just as brittle as another PA6-GF plastic. The shiny-smooth one is just harder to achieve in mass production. Troll's arrogance just either shows his lack of knowledge or his praised brand representative's approach at sales trainings. He's too predictable

Sorry for the late reply. I have to correct myself - the blades are double sharped. Anyway, with it's reduction ratio it goes through stuff quite easy - I've cut some branches thick as thumb while shaping some thujas. I was way more concerned to have some oil for cutters (sap-o-phobia? ). Didn't notice any lack of power - I think there's quite enough for a longer blade.

I'd say HCR-165ES (if blade length is fine for you). It has triple sharped, double sided, double action cutters that give very fine cut quality plus a very handy rotatable handle. There are obviously more features. Give it a look at dealers store

You mean ground saW? 501SX is the second generation 50cc saw that is lighter than competition. 620SX should also be compared to Husky 562 not 560 (oil/fuel tank sizes prove that). The ~150g weight difference doesn't look that big then, especially considering higher torque below 9000rpm which also comes from longer piston stroke.

Actual reason for Echoes running lean is 5-10% of ethanol in the fuel, although all the Echo engines are factory-adjusted in Japan where they do not use ethanol. Dealers MUST re-adjust them Husky 550XP AFAIR is AutoTune unit, so it re-adjusts the carb itself.

CS-501SX should do well. The powerband is way wider than previous model (CS-510) and the weight is the lowest you can find for 50cc saw. And it's very durable/reliable.

Yes, both laminated and solid ones have stellite inserts. At least For EU all optional 1/4 bars are small tip carving bars.

The original 3/8 sprocket won't fit both chains (although the bar could, except the tip). Here's how different both chains are in cutter sizes and how they both differently fit the 1/4" sprocket:

2510 is in different league - when you put it side by side to 260/280 it looks even tinier. What's even more impressive - it has a carb heating channel, roller catcher, metal spikes and fixed bar nut yet it weighs half a kilo less than 260. Don't put it side by side to your 260 unless you're selling it )))

Well as far as I remember JASO reserves the right to purchase a sample of certified oil at any moment and re-test if it is the same spec as it was given for certification. This is one of the reasons why their certification itself is not cheap - for sample testing they use lab-spec engines under heavy conditions for 180 minutes for sole sample. Typically it's easy to see if modern engine was using FB grade (this means pretty basic) oil - heavy carbon deposits are very clearly visible everywhere after as little as 20-50 hours of actual work. The cleanest engines that I've seen were the ones that used Aspen or FD oils. And answering to your question - it's up to You IMHO independent testing always says the most. The only exception is when manufacturer's machinery suffers from certain problems and a spec-formula as a solution has to be developed. This was remotely similar when VW tried to solve DSG gearbox failures by changing the tranny oil to synthetic spec (and it did not help that much:) )

It is a bit simplier and at the same time might seem more complicated than that 1. JASO and ISO standards actually are very close (FD is nearly equal to LEGD) 2. Many oil makers (and re-badgers) use standard names on bottles without actually having the certificates or being certified. Yes, even the big names do that, I will just avoid naming them 3. The semi-synthetic (or "synthetic blend"=mineral based+synth.additives) oils can easily have a better set of characteristics and be superior to synthetic based oils. The reason is not really complicated - the oil has to have certain set of important characteristics of lubricity, carbon/ash deposits, detergency, smoke amount etc. If one of them is lower than required by standard - it has lower rating 4. The beauty of JASO procedure - the oil maker/brand can always be checked even online (which is not so easy with ISO). Also, in most cases you can find a square symbol on oil bottle with actual certificate number given for that oil. The list of oils that are actually certified can be found here: http://www.jalos.or.jp/onfile/pdf/2T_EV_LIST.pdf The description of application and AFAIR testing procedures can be found here: JASO Engine Oil Standards Implementation Panel Now check the thread and your own post and you may notice that some names/pictures of oils mentioned actually are not JASO certified although you can find the "statements" on the bottles. Same story is with ISO ratings, however it's very hard for average Joe to check if certain oil is actully ISO certified. This is the reason why many non-sponsored kart and 2-stroke bike racers stick to FD oils (and yes, they fight over which one is better ) Happy reading!

Enjoy that deep clearly articulated stroker sound And make sure you have it readjusted after few gallons - it will loosen up and start idling higher. And gain some power