Change 550 for mkii

[Stubby]

1 hour ago, huskykev said:

Wasn’t the 562 upgraded early last year? Couple more vents in the top cover and an extra heat shield...

Yes and a magnesium crank case half I believe

[adw]

They were always magnesium Stubby, the 560 gained an aluminum half, the 550 gained a new carb the AT12 with a metal metering diaphragm, this was to give better acceleration and get rid of the flat spot, the fuel hose was also moved further away from the rear of the cylinder and a slot in the top cover all to reduce temperature, the ring peg pin has moved a few times due to them coming loose ( also on the 560 ), improved main bearing cage material, an additional screw in the crankcase, improved sprocket and bearing, new orange frame filter 25 micron.

[Stubby]

Just now, adw said:

They were always magnesium Stubby, the 560 gained an aluminum half, the 550 gained a new carb the AT12 with a metal metering diaphragm, this was to give better acceleration and get rid of the flat spot, the fuel hose was also moved further away from the rear of the cylinder and a slot in the top cover all to reduce temperature, the ring peg pin has moved a few times due to them coming loose ( also on the 560 ), improved main bearing cage material, an additional screw in the crankcase, improved sprocket and bearing, new orange frame filter 25 micron.

Ah , yes Andrew . I remember it being a different material when you told me ! I also remember saying to you that I wondered about the different coefficient of expansion between the two materials . One case half one material and the other a different one .  Obviously its not been a problem . Thanks for the reminder my friend ? 

[adw]

The mark 11 550xp is so different to the mark 1 i don't know where to start the brief was reduce engine temperature and increase engine life, the crankcase is no longer painted so doesn't look like death after a week or two from the paint falling off, they run much nicer too.

[Kay 9]

4 hours ago, adw said:

The mark 11 550xp is so different to the mark 1 i don't know where to start the brief was reduce engine temperature and increase engine life, the crankcase is no longer painted so doesn't look like death after a week or two from the paint falling off, they run much nicer too.

What's the mk2 crankcase made of. Thanks

[adw]

Magnesium, only the 560 has aluminium on the drive side.

[Kay 9]

Got a chance to use the new 550 for the first time this morning. First impressions are good. 

Noticeably faster pickup and torque than the old. 

Took a half a tank for it to run right but it's still improving.

I've a 13" bar and chain on for now but the mkii will be living with a 15" when it arrives.

The extra weight everyone is raving about isn't noticeable to me. 

Mind you I'm 6'3 and 18 stone so it shouldn't bother me. 

Overall, 

I'm pleasantly surprised that the two saws differ. Didn't think they could improve it that much. 

I'd reccomend

[Ian C]

are they any more reliable? I have had a 550 and 2 560's, all a PITA starting and lasted 18 months before going pop, the 550 went pop at tickover! all run on aspen like all our other kit and only ever had problems with the new huskys!

[wicklamulla]

i've only heard of one MK2 550 going bang after a few weeks from new,  twas all put right though.

[Kay 9]

11 hours ago, Ian C said:

are they any more reliable? I have had a 550 and 2 560's, all a PITA starting and lasted 18 months before going pop, the 550 went pop at tickover! all run on aspen like all our other kit and only ever had problems with the new huskys!

Supposed be more reliable than the outgoing version. Mind you I've the mk1 since 2012 and it's been trouble free. Have run aspen too. 

Sorry to hear you've had trouble with yours. Maybe I'm one of the lucky ones. 

What do you use yours for?