Husqvarna 51 Needs New Piston/Cylinder and TLC

[IH1972]

I picked up a rather sad and tired 51 the other day for cheap and am interested in using it to learn about working on saws.
The piston is scored badly and it has low compression. Additionally, it's missing the pull cord/handle and chain brake band.
What's the current best option for a piston and cylinder? I see Meteor kits available that would convert it to a 55 and some of them have a closed port design, which is something that I would like to try. I have another 51 and a 55 so I'm familiar with these saws, but have never attempted a full rebuild like this one needs. I've worked as a mechanic for much of my adult life, so I know how to wrench on things.
Where's the best place to get a new piston and cylinder?
Thanks!

 

[ammoaddict]

You can still buy OEM open port piston and cylinder kits probably cheaper than meteor. Check the site sponsor hl supply. I would put crank seals in it while you're at it. Good time to do a base gasket delete, timing advance and muffler mod.

 

[IH1972]

You can still buy OEM open port piston and cylinder kits probably cheaper than meteor. Check the site sponsor hl supply. I would put crank seals in it while you're at it. Good time to do a base gasket delete, timing advance and muffler mod.

I believe my 55 is a closed port and I would like to go that route for this saw. It has a good bit more power than my other 51.
I was planning on a MM and BGD, but don't know anything really about modifying the timing. I assume that is done through changing the porting?

 

[Stump Shot]

https://www.hlsproparts.com/category-s/1703.htm?searching=Y&sort=2&cat=1703&show=30&page=1

 

[IH1972]

https://www.hlsproparts.com/category-s/1703.htm?searching=Y&sort=2&cat=1703&show=30&page=1

It appears that the Meteor kit they offer is an open port while the Hyway is available in closed port. Is there any difference in quality/longevity between the two? Are they both good quality parts?
It also appears that the OE Husqvarna kit is available for essentially the same money as the Hyway and Meteor options.

 

[Stump Shot]

It appears that the Meteor kit they offer is an open port while the Hyway is available in closed port. Is there any difference in quality/longevity between the two? Are they both good quality parts?
It also appears that the OE Husqvarna kit is available for essentially the same money as the Hyway and Meteor options.

OEM for that $$$ is going to be the best option for you.

 

[IH1972]

OEM for that $$$ is going to be the best option for you.

Reckon why the aftermarket parts are as much as the OE stuff? In other words, why would someone select a Hyway or Meteor if OE is the same price?

 

[ammoaddict]

I believe my 55 is a closed port and I would like to go that route for this saw. It has a good bit more power than my other 51.
I was planning on a MM and BGD, but don't know anything really about modifying the timing. I assume that is done through changing the porting?

Timing is advanced by filing off some of the flywheel key and turning the flywheel so it passes the coil sooner before top dead center. There are threads on this that can explain it better than I can.

 

[IH1972]

Timing is advanced by filing off some of the flywheel key and turning the flywheel so it passes the coil sooner before top dead center. There are threads on this that can explain it better than I can.

I understood what you meant. I'm familiar with advancing ignition timing.
About how much advance is added to a work saw to be beneficial?

 

[ammoaddict]

I understood what you meant. I'm familiar with advancing ignition timing.
About how much advance is added to a work saw to be beneficial?

I can't remember how much I did mine. Maybe a quarter of the key. I read several threads on it before I did it.

 

[Stump Shot]

Reckon why the aftermarket parts are as much as the OE stuff? In other words, why would someone select a Hyway or Meteor if OE is the same price?

Exactly

 

[Stump Shot]

I understood what you meant. I'm familiar with advancing ignition timing.
About how much advance is added to a work saw to be beneficial?

About 6 degrees of advance will do you good.

 

[IH1972]

Exactly

If I want a closed port cylinder, the only option appears to be aftermarket. Of course I'd rather have an OE piston/cylinder, but those are now NLA.
This saw is going to be a play/learning saw as I have other work saws, so I may try to find a closed port Meteor kit. I've read that they might be slightly higher quality than Hyway.
In the meantime, I'll read up on ignition advance.

 

[5155]

Husqvarna 50/51/55 repair thread.

I have a couple of 55s in the que for work, so this thread is going to cover several different saws as I get to them. Today was a piston replacement, pretty standard job on these older saws. The victim.

opeforum.com

Here's a good read, there are others.
No guarantee the link will work.

 

[5155]

If I had to have closed port I'd run a wanted OEM closed port for 55 on here.

 

[Normzilla]

I believe my 55 is a closed port and I would like to go that route for this saw. It has a good bit more power than my other 51.
I was planning on a MM and BGD, but don't know anything really about modifying the timing. I assume that is done through changing the porting? What style port is the OEM 51 cylinder? Wondering if powered difference is due to 55 being slightly up on ccs. I was fortunate just found a 51 on marketplace with case, extra chains etc 100.00 he was asking 150.00 but I'll have to work on chain brake. So he took 100.00 super clean low hour. They are going for around 350.00 here in CA. The 51 is my favorite saw for a 20 inch bar. I run 3/8 full skip very well. It actually gives them a good bump in cutting performance.

 

[IH1972]

Husqvarna 50/51/55 repair thread.

I have a couple of 55s in the que for work, so this thread is going to cover several different saws as I get to them. Today was a piston replacement, pretty standard job on these older saws. The victim.

opeforum.com

Here's a good read, there are others.
No guarantee the link will work.

Thanks for the link.
I may look for an OE closed port P&C.

Normzilla, It's my understanding that all 51's are open port.

 

[Stump Shot]

I wouldn't be scared of an open port on this series saw, not one bit.
The closed port 55 is actually the 51 bore dia. so how are you going to win big?

 

[IH1972]

I wouldn't be scared of an open port on this series saw, not one bit.
The closed port 55 is actually the 51 bore dia. so how are you going to win big?

I'm not scared as I already have a OP 51 and like the saw, but my closed port 55 runs a little stronger.
I'm not looking to win big, I would just prefer to have a closed port if I'm going to rebuild something. I've got much larger saws if I want to run something with more power.

 

[ammoaddict]

Thanks for the link.
I may look for an OE closed port P&C.

Normzilla, It's my understanding that all 51's are open port.

Yes 51 is 45mm open, 50 is 44mm open, 55 is 46mm open except for the few closed port ones and I think they are 45mm.
There's a chance that the oem cylinder will clean up with some scotchbrite . I got a 55 that the piston was heavily scored, I thought the cylinder was too. It took a little work but I got it cleaned up, you can still see a couple score lines in it but you can't feel them with your fingernail. I put a meteor piston with caber ring in it and it runs very good.
The best advice I can give you is Don't fix this saw. If you do and it runs good, you are going to want another and another and another. You will have CAD like most of us here and there is no known cure.