Husky 51and 61 head repairs?

[J & L Creations]

hello guys, I am in the process of rebuilding a husky 51, found a low and upper end rebuild kit. I have the old head and was wondering what could be done with it. Can it be machined an reused with a larger piston or is it worth it?
Also I have a husky 61 the muffler blew off of as the saw was in use. It blew off at such a force that the muffler bolt threads in the head pulled out. My guess is that the two piece ignition stopped sparking the spark plug, fuel built up in the hot muffler and ignited, which caused the muffler to explode internally and shear the threads and the reason I am now replacing the two piece ignition. I'm not sure this is what happened but would explain the threads in the head from being sheared and the extra hole in the muffler. So now to the question, what would you recommend as a repair, larger muffler bolts, or heli-coils and the same bolts. Either way I will have to rethread the head to a larger size. I thought about welding them up then rethreading to the standard size, but am fearful that welding it would warp the head.
I might also have to split the case to replace the gaskets and seals.

 

[lwhaples]

I would Heli coil,unless you don't have enough material left. Not sure I understand the 51,you are wanting to bore it larger?If that's right,then not worth it. Seals can be done without splitting the case on the 61.Not sure why the need for gaskets. Good Luck.

 

[J & L Creations]

Yes there should be enough room for helicoils, I'll use the old head as a fishing weight. I know about the seals, but when the muffler exploded if the piston was in the open position to the crank, this could have pressurized the crankcase and could have blown the gasket, Hence the need for seal replacement also, just thinking of possibilities. Thanks for the feedback, Jeff.

 

[beaglebriar]

Are you positive the 51 cylinder is junk? A lot of the time the aluminum transfer (scoring) can be cleaned up. Post up some pictures of what you have so we can give a better assessment.

 

[J & L Creations]

You know you could be right, it really does not look that bad, the piston does on the intake side. I'll post some photos, thanks.

 

[beaglebriar]

Check out Masterminds post on cylinder clean up in the Technical area. You can get the same result with hand sanding but it takes a while longer.

 

[J & L Creations]

Ok, here are the cylinder and piston photos. Thanks.

 

[beaglebriar]

I'm sure that'll clean up. New piston/ ring probably crank bearings and seals. You'll be good to go. Just make sure there's no air leak around the intake when you put it back together.

 

[J & L Creations]

Ok, speaking of the intake seal, I was looking but could not locate one, any ideas?

 

[beaglebriar]

You mean the intake boot? Should be able to get one from your dealer. Or you can support the forum host HL supply. I'm sure they have everything you'll need.

 

[J & L Creations]

Yes, ok thanks.

 

[J & L Creations]

Here's the 51 almost completely torn down. Waiting on delivery of the oil pump worm gear puller so I can remove the crankshaft and replace the bearings and seals. If/when I get into repairing chainsaws for other people deeply, I will need to build a seal puller, the ones I have seen online are $200.00 plus, there's no way I'll pay that when I can build one. Here's a photo.