A, B, and AB cylinders

[Tor R]

I am not 100% sure, but I think Husky/JRed left this A and B piston system for a decade ago...
It can't be a huge issue, there hasnt been an options to choose A or B pistons on most Husky 2xx and 3xx and so on.
I have a brand new Husky 262 C&P, jug is A, piston AB.

 

[Landmark]

I have a brand new Husky 262 C&P,

Now you're just bragging.

 

[MustangMike]

The MS440 I just ripped down is the same, A jug, A/B piston. I think it is original, but not positive.

 

[trooney]

Well I ran it tonight and it made a little difference. I can get it up to 12.75 k. Not to my liking though. There must be something else wrong. Every once in a while it backfires through the carb. Ignition maybe? But the piston did help it out a little bit. Maybe try another A cylinder? I'll go thruogh it tomorrow nite to make sure everything in the ignition is right. What I'm thinking is the backfiring is caused by timing? Is this correct? And if so, how do you correct?

 

[Tor R]

Now you're just bragging.

hehehe sure

 

[trooney]

Well, I got it running good. Seems the flywheel key had sheared off (second one, whats up with that, crank turns nice). Marked the flywheel where the key was, lined it up, and tightened it down real good. Readjusted coil clearance and installed a new spark plug. 13.3k at 1 1/4 L, 7/8 H. Idles about 3k. So it wasn't all the cylinder and piston but it did make a little difference. All in all I think in the future I'll pay more attention to the cylinder and match it up with the piston. I love these threads because I learn so much. Thanks to all. I hope my neighbor is happy with his saw because I am!!

 

[VinceGU05]

Oops, sorry @Landmark , I reread your post. But I'm still curious if it might have contributed to the loss of power.

the fresh rings with the new piston?

 

[trooney]

no, i installed an AB piston that I had that might have had an hour run time on it. The piston looked almost new and the ring was good. I will mate up the B piston with the B cylinder and have another one good to go. The B piston was a brand new meteor that I had originally installed. The one I got from Redfin had a new ring on it and it still would only get 12k. Til I put a new meteor in and then it would power up fine. I wish I knew about it then when it happened so I could see if it was piston size that contributed to the loss of power. I think I've still got that piston somewhere. It would be interesting to see what it is compared to the jug.

 

[Tor R]

no, i installed an AB piston that I had that might have had an hour run time on it. The piston looked almost new and the ring was good. I will mate up the B piston with the B cylinder and have another one good to go. The B piston was a brand new meteor that I had originally installed. The one I got from Redfin had a new ring on it and it still would only get 12k. Til I put a new meteor in and then it would power up fine. I wish I knew about it then when it happened so I could see if it was piston size that contributed to the loss of power. I think I've still got that piston somewhere. It would be interesting to see what it is compared to the jug.

the way I understand you is that you had trouble with A jug and B piston combination, and you solved the issue with an AB oem piston in an A cylinder?

 

[trooney]

That is correct. It wasn't responsible for the total power loss, but I think it contributed some to it. I gained almost 1k by switching pistons. From now on I'll be matching them up. Don't know about the mechanics enough to say why.

 

[Tor R]

That is correct. It wasn't responsible for the total power loss, but I think it contributed some to it. I gained almost 1k by switching pistons. From now on I'll be matching them up. Don't know about the mechanics enough to say why.

can also be that OEM piston is lighter then Meteor, that a bit of your gain comes because of lighter piston.
I wish I had taken time to weight that 254 Meteor AB vs Husky AB.
I sure gone check the weight on 262 pistons vs oem when I get them from the greek.

 

[trooney]

dont know...maybe...

 

[radio]

I have a Husky 50sp that has an A cylinder and an AB piston from 1989 and another with a B cylinder and AB piston from 1990. Seems that Husqvarna went to the generic AB piston fitment quite some time ago.