Toad

I hadn't appreciated the difference between the chains. I know in the real world a saw with a .325 chain may well end up holding higher rpm in the cut than one with a 3/8 chain, but I thought it was really interesting when looking at 7 pin and 8 pin sprockets vs different chain pitches.

It's the length between the drive links essentially. The chain speed should be distance between drive links x no. Of teeth x engine speed/60

I was having a little think about chain speeds in relation to my initial question about going with a .325 or a 3/8 chain over the last few days and sat down last night to work them out. Basing the calculations on the quoted max power engine speed of 9600rpm A .325 chain with a 7 tooth rim has a chain speed of 18.49m/s A .325 chain with an 8 tooth rim has a chain speed of 21.13m/s A 3/8 chain with a 7 tooth rim has a chain speed of 21.34m/s A 3/8 chain with an 8 tooth rim has a chain speed of 24.38m/s

I don't know the saw, but is that part just a heat shield, and no exhaust gases will come out through those holes?

As I understand it, the 550 is the professional saw, the 450 is the landowner saw so kind of semi-pro. The build qualities will reflect this as does the price. The 550 has the magnesium two piece crankcase with the cylinder bolted on top, the 450 is the clamshell crankcase, so is built stronger as you said. The autotune on the 550 will monitor the engine speeds and adjust the fuel mix constantly, so you will never have to worry about tuning it yourself and it'll deal with changes in fuel, temperature and altitude for you. A lot of people complain about modern saws not lasting as long as the previous generations, but things like the 550 have been designed to run on as little fuel as possible which in turn reduces the oil available for lubrication, hence it is really important to use good quality oil. As someone cutting firewood, the 550 will probably see the equivalent of a couple of days worth of professional use every year, so should last forever.

Many roads are also within people's deeds, however this is something that is easily misconstrued as giving people the right to undertake works, modify or obstruct the highway. Legally the public have the right to pass and repass on the land and there are various laws that allow the local authority to enforce this. I would start with talking to the rights of way team as you suggest. If the first thing they know about works there is Mrs Miggins going mental about getting muddy while walking her poodle then they're less likely to look upon the work favourably. Can the extraction be undertaken in the summer or autumn when damage to the bridleway is likely to be reduced?

Meteor piston and clean up the original cylinder?

Thanks Steve. As far as I know it is a late cylinder. It has good compression, and apart from the knackered crank didn't seem to have had much done to it although many of the bolts were nowhere near what I would consider tight when I stripped it. I do have a spare piston and early cylinder from the donor saw, plus a spare flywheel side of the crankcase if anyone is desperate for one.

Here are pictures of the carb. The lettering I could read on it was EL42 OZA.

Ah ok. I did wonder I tried blowing down it tonight to see what happened. I'm glad nobody saw me doing it.

Did the late saws have this union too? I didn't notice it on stripping and assumed that it wasn't fitted to this saw as it already had the decomp in the cylinder.

The plate on the side shows it is a late saw and it has a normal push button decomp on it, however, the one I got for spares with it was an early saw which did have the auto decompression so I wonder if it's been swapped on in the past. Sadly I know nothing of it's history other than it ended up on Ebay with a knackered crankshaft.

I'll get more photos and check the part no. on the filter too. I just assumed it was correct, but the gasket between the filter holder and the carb just didn't seem quite right, the spindle for the choke butterfly for example is slightly exposed to the elements. If it makes any difference, there is a small tube that runs up into the filter that looks like it ought to provide airflow for a strato port or something. I don't remember looking at the carb to see where it went. I'll see if I can get more identifying marks from the carb too. Thanks for your interest!

Ah, awesome. Thanks for the explanation. I think it is the Zama carb. I did briefly look for the model/identification when I cleaned it, and remember seeing C3 cast on the body, so I assume it is the C3 EL42 carb.

I took lots of pictures to help remind me how it came apart, so I have some of the carb, mostly covered in filth. Not sure if they help? It's a 2011 saw I think.

I was really impressed with it this afternoon. Just hope it wasn't a fluke!

When you say compensator carb, what do you mean exactly?

And now I've checked the manual I realise the max engine speed is 14000rpm, so I don't have to dick around with the carb. Sometimes I really need to remember to double check the manual.

So, finished reconstruction today. Had about ten minutes of looking for where I hid the coil bolts from myself, and the clip for the intake boot is a total bastard to do up, I assume with some shaped pliers it would be fairly easy though. Fired it up with a new bar and chain on, and let it clear all the excess oil I'd used for lubricating the bearings and piston. It started and restarted nice and easily. I didn't do much to the carb on it apart from check the gauze filter was clear, and left the settings it arrived with on the carb when I took it to have a bit of a test with some bits of wood on my pile. The saw went really well in my opinion, was surprised how quickly it nibbled through some admittedly past it's best beech, but the idle was staying a little bit high at the end of cuts and slowly dropping back down. I had a check with my taxi and found the idle was a little bit high at over 3000rpm, so I backed the idle speed screw out a bit which settled it. Max rpm was around 13900, which is a bit fast, but I found the H jet to be against the limiter - it's the not fully adjustable epa carb on this one. - so I couldn't bring it down. I'm tempted to remove the limiters and see if that let's me slow it a bit, or if there is another issue. I did try adjusting the L jet but it became very boggy if I increased that one. Now going to have a little panic that the issue is that I didn't distress the bearings and they've cooked themselves and the seals and that's why it's running fast. I'm sure it'll only play on my mind for a few weeks. ?‍♂️

I think that one is heading for the bin! My father has been collecting random things and stripping all the non ferrous metals out of them to scrap. Sadly I think he's making about 50p per hour at this rate.

Oops! I spun it over by hand once it was all together and it was nice and free so didn't bother. I may come to regret that!

Finally made some progress on it today. Stripped the complete saw down, put the case halves in the sink with plenty of hot water and fairy liquid to soak and they cleaned up well. Pressed the good crank out of the donor case and had a few issues with one bearing sticking to the crank. Should have waited to get a small puller but muddled through. Gave it a good clean up, washed the big end out with petrol, blew it out with the air line and put plenty of two stroke oil in it before fitting it. The new bearings dropped in quite easily with the use of the heat gun to expand the cases, and the crankshaft pulled into the bearings quite smoothly. I've loctited the bolts holding the crankcase together and wound them in nice and tight. I used a GTS crankcase gasket, and wasn't especially impressed with the fit. Next time I'll go genuine. I've fitted a new fuel line and filter to the tank and then called it a day. I think I'm going to fit the crankcase to the tank, then carb plate, then piston and carb as it seems an easier way to thread the fuel and vent pipes through.

I assume the flywheel is the same sort of thing as other husqvarna saws with a little bump cast into it instead of a proper key? You might be able to put a steel key in the crankshaft and file a slot into the flywheel for it to fit into. Afaik the taper should hold the flywheel rather than relying on the key to be under torque, so you may be able to line the keyless flywheel up and tighten it down properly. I did this with a huztl 372 I built and tore the key out of. I did eventually replace the flywheel for peace of mind, but it ran ok. I just used a marker pen to mark the relative positions of the key and key way before fitting. As for changing the timing. No idea, but pushing a milling saw to it's limit might expedite it's demise.

I need to have more of a look at them when I pootle down there next. I thought I'd seen the cabling certainly on the westbound. I did pop to Gosport with a colleague who struggled with the average part of the speed cameras, speeding up between and slowing for each camera. I'm curious but don't want to actually ask if he got a ticket.