bmp01

Brake band is number 10 and lever to operate it no 11. Brake band would squeeze the clutch drum 12 to stop the drum spinning. I know exactly the noise you're talking about when you refer to a skate board wheel, noise from my youth. Can't help but feel that would get downed out by the engine. Even the blades make a racket. You could take the blades off and run it again - see if you learn something....

Sorry, think I had my head up my backside back there. Clutch bearing is in the housing 1 below the clutch drum, item 3 in picture below ? Ball race bearings usually pretty quiet from new usually get louder with age but hardly, not much being in. I struggle to believe you'd hear a bearing above the engine. It's more likely to be gear whine ... If the old bearing was totally knackered, clutch won't have been running true, might have implications for the gear. Or maybe the brake band rubbing on the outside of the drum ?

Assume the crank is still OK ? The bearing is spinning at idle and up to point the clutch engages in drum. Once engine speed is high enough the bearing is stationary, is that consistent with the nose you hear ? A word of warning, don't run the engine above idle without the clutch drum fitted, otherwise theres nothing to stop the clutch weights from ever expanding.

For a short while, yes. Then it becomes something else. Just like all of them accelerator piston circuits. Aftermarket carbs although hit and miss on quality don't have this feature.

I'd like to see them put these engines into the housing in the factory. Seems to be a real puzzle wiggling it into place while the engine pan is sitting loosely on the upper clamshell. Prefer the older 170/180 in that respect - still a fiddle but at least the engine is assembled tight at that stage. Here's what I did to a 181.... makes life a lot easier but not exactly practical for a DIY.

It's had a real good chemical clean and a fair bit of abrasion to get to where it is now. Any other cylinder I've done would be as clean as a whistle by now. Just rebuilding it with a new piston is an option, see if it survives, then pull it apart for some tuning work. They come apart pretty quick. On the other hand new OEM 385XP cylinders are available on eBay for reasonable money. Do both...

That'll more than double the price of the saw. Husky cylinder& piston .....300 quid to you sir. Should have resisted the temptation to rip it apart before leak checking. Ran fine cross cutting, short cuts though. Aftermarket 390 pistons (before Meteor brought one to the market) don't have a good rep, I'm gonna say it was that plus already knackered cylinder

Feels like the right thing to do, fixing the existing. Wonder if blind cylinders are within their experience band. ...

Hi Toad, I will check bearing spinning issue, good shout. I've been to see your thread on the subject, I'll check year of manufacture too. And thanks for kind offer of cylinder, looking for known brand I think.

Don't know the history of this one but it looks like it has some previous. Bought the saw secondhand and I seized it (probably for the second time in its life) whilst doing a 12 inch milling cut after 2'ish metres. Bottom end is rock solid. Top end less so, aftermarket piston was in there and its now trashed. Couple of piccys attached showing the cylinder condition after chemical and mechanical cleaning. White paper disk at the top of the bore - hopefully better picture. As well as the obvious scoring/discolouration in the bore, can you see the plating has been removed along bottom edge of the exhaust port ? One picture is taken looking down the inlet port just catching this detail. I'm guessing this plating removal was part of the previous clean up when the aftermarket piston was fitted. Just for good measure top cooling fin is busted too, which fits in with the plastics damage. Saws not had an easy life, but being what it is I think it's worth saving. Cylinder is a lost cause, certainly not a good place to start if I'm going to spend time porting etc. Replacement options; genuine (too expensive), secondhand (like rocking horse poo), aftermarket (most likely) meteor, hyway. I've tried our Greek friend, he doesn't stock either. Plenty of Meteor in USA on ebay but not here. Any one have experience with 390 cylinders? Other suggestions?

Nothing scientific, just scratchy tools. Flat surfaces - I use knife blade something line a Stanley blade, the fake o ring groove - small screwdriver followed by drill bit (blunt end) with end ground square, groove doesn't need to be perfect. It's a PITA and a consumer of time.... Not found anything to dissolve the cack which I suppose can be seen as a good thing in service. I like Stubby's suggestion, when it's back together. Similarly, taking the bar and chain off might help to locate the problem.

Presume it's a standard piston (not aftermarket) and there isn't a mega amount of carbon on piston or in the combustion chamber ?

Thanks for the update Dinosaw. That's a real puzzle then, but as it has the standard side cover at least that explains why you can feel the compression cycle on the starter cord - you would not feel it with easy start side cover. How about the side cover has been swapped to a std one but they fitted a starter pulley from a different saw - a small pulley requiring more pull on the cord to give the same torque on the crank ? Maybe the easy start model has a smaller pulley ? Bit of a punt....

But it pulls over OK without the plug in. .... that's where it gets confusing.

Have you had a look at the thread "MS211C weird problem", different machine obviously but same problem....

Find anything out of the ordinary ?

Muffler mod it ? ....

They said 30 mins of leaf blower not 50 hours.... Anyway its about how much fuel each machine uses. What's a typical L/100km number for vehicle? Lets say 5 (optimistically)......thats 150 L then. Leaf blower .... dunno.... 0.5 L max ? Ok so vehicles cleaner running with cat etc but at least 300 times the fuel ... sounds like a croc. And producing the fuel, how clean is that ?

Be interesting to see what's up with it. Still got my money on the easy start mechanism. If it was working properly it effectively decouples the engine from the pull start - all you are doing with the pull start is winding up a biggish clock spring, so you don't feel the compression stroke. I bet it broke and has been bodged somewhere along the lines . ... Google ergostart for utube vids demonstrating the easy start.

It's a clamshell engine - no separate cylinder (so no gasket between cylinder and crankcase). You can bump up the compression eg taller piston or change the crank centreline.

Is that the "Easy Start" model being the 'C' ? If so, it's got an extra spring between the pull cord and the crank.... I'd be looking there. Actually, I'd take that start cover off, toss it over my shoulder and reach for a standard side cover to try.

Firstly, well done in sorting it out and not giving up. WRT seeing a spark, that goes to prove the test isn't adequate. As stated earlier you need to get a spark to jump 4 - 5 mm in free air to be confident there will be a spark in the cylinder with compression. And when the coil and ht lead is put under load you might find the insulation breaks down somewhere in side the coil or through the side of the ht lead. Or it might be the spark is good but the coil timing gone for a poop. Anyway, it's the result that counts, nice one.

How long between the last time it was used and now when it won't start? You'd put money it being a fueling issue wouldn't you. Try some easy start spray, should run for a few seconds and if it does then you can say ignition is OK. Did you check the metering arm height when you were in the carb ? The thing is, using the purge bulb draws fuel through the carb but it will also pull air the wrong way through the tiny low speed jets (its why you always get some tiny bubbles in the bulb), i just wonder if the metering diaphram has stiffened slightly while not in use and if the metering arm height was marginal maybe it's the opposite to what you think and not getting fuel. ... just thinking aloud. .. Nah, that's cobblers; on choke the engine will stuck fuel through .... But try the easy start. And try the hot plug.

That's bad luck should have picked up a clue with all your tests. Couple of things to try, might help might not. - heat the plug with hot air gun or blow torch till you need gloves to fit it. You might have evaporated excess fuel but that's probably left 2 stroke oil behind, might be gunking up the plug, hot plug helps. - a spark jumping a std spark plug gap isn't necessarily adequate when its in a cylinder with compression you want to jump a 4 or 5 mm gap. - timing might be off if the electronics in the coil are up the creek. Most coils will have an advance curve so it's retarded for easy starting and increases above idle for better performance. - un route the ht lead so its in free air, if it has shorted to housing or wires etc you won't know it, you might learn something from trying the big air gap spark test. - I'm guessing you've checked to flywheel gap. Keep at it, sledge hammer might give you some satisfaction but it'll have beaten you if you go that route.

In my case a 395XP. Same thing sheared the key, didnt clean the taper, doh. If you get lucky, there is just enough evidence of where the key was - so trial assemble like that to sort your alignment (use a piston stop and mark the outside of flywheel to some feature on the housing...or coil). If you're unlucky (no evidence) you need a machine to copy or as you say use a strobe and trial and error. Disassemble. Use fine lapping paste to mate the two surfaces. Clean thoroughly. Repeat as necessary. Assemble dry or with loctite, epoxy, Devcon, JB Weld, what ever takes your fancy and dependant on how ripped up the surface is. Take care not to shift the flywheel as the nut is torqued up. DO torque the nut up. I'm not inventor of any of this procedure - it's pretty common place for the US modders to want timing beyond the half a key mod. And of course Mr Spud here has fixed many a machine without resorting to new flywheel.