Husqy 55 covers burning.

[biggerstaff94]

Has anyone figured out a way to keep the Top and clutch covers from burning on a 55/51. I just had my 55 overhauled and picked up some nice oem covers from ebay for it. Ive put it to work twice and the top cover was already getting a little saggy. I heated it up and bent it back but id like to address the issue before i toast $150 in covers.

 

[Wood Doctor]

Could be an exhaust leak. Check the muffler, especially. That's probably what's generating the heat -- exhaust gas not going out the port. Spark screen could be clogged up and/or the assembly is a tad loose..

 

[biggerstaff94]

Could be an exhaust leak. Check the muffler, especially. That's probably what's generating the heat -- exhaust gas not going out the port. Spark screen could be clogged up and/or the assembly is a tad loose..

I dont think so, the top cover would be black where it gets hot if it was an exhaust leak. I think its just from being to close to the muffler. My old top cover did the same. The exhaust port on the muffler is pointed at the front of the clutch cover and thats what melted my old one. The new one has soot on it but no burn marks yet. I assume it’ll develop them the more i run it.

Maybe make a custom muffler? The OEM muffler is in great shape still, i scrubbed the screen with a wire wheel during the overhaul. Seems like a common problem on the 51/55s. Ive seen alot on ebay and even the really nice ones have some sort of burn.

 

[SimonHS]

Its dont think so, the top cover would be black where it gets hot if it was an exhaust leak. I think its just from being to close to the muffler. My old top cover did the same. The exhaust port on the muffler is pointed at the front of the clutch cover and thats what melted my old one. The new one has soot on it but no burn marks yet. I assume it’ll develop them the more i run it.

Maybe make a custom muffler? The OEM muffler is in great shape still, i scrubbed the screen with a wire wheel during the overhaul. Seems like a common problem on the 51/55s. Ive seen alot on ebay and even the really nice ones have some sort of burn.

Muffler tape stuck inside the covers? Worth a try for little cost.

https://www.arboristsite.com/threads/heat-shield-foil-under-muffler-alternative.282003/

 

[Den]

Husqvarna 55 is one of my favorite's.
Out of the 11 Husky 55 saws I have, I think 2 of them have some of that warpage/heat problem. Several of them have a kind of "tin foil" type of heat tape on the underside of the top cover. I believe SimonHS was referring to that when he said muffler tape.
I'd give that a try. Also, a muffler mod wake's them up, and dissipates heat better.

.

 

[biggerstaff94]

Husqvarna 55 is one of my favorite's.
Out of the 11 Husky 55 saws I have, I think 2 of them have some of that warpage/heat problem. Several of them have a kind of "tin foil" type of heat tape on the underside of the top cover. I believe SimonHS was referring to that when he said muffler tape.
I'd give that a try. Also, a muffler mod wake's them up, and dissipates heat better.

.

Yeah same, its my top pick of my saws. Ill pick some up and give it a try. I will probably muffler mod it in the near future. I’m a machinist so im thinking a machined aluminum bark box inspired muffler with cooling fins on the base may be in the plans. Maybe a machined in port extension for a little more down low grunt or is that theroy bs?

 

[Wood Doctor]

"I don't think so, the top cover would be black where it gets hot if it was an exhaust leak."
------------------
However I can show you a Sthl MS 661cm that has a hole clear through the top shroud about the size of a quarter, right above the muffler, and almost nothing is black inside the shroud. That surprised me also. I discovered the muffler was a tad loose, so it doesn't take much..

 

[biggerstaff94]

"I don't think so, the top cover would be black where it gets hot if it was an exhaust leak."
------------------
However I can show you a Sthl MS 661cm that has a hole clear through the top shroud about the size of a quarter, right above the muffler, and almost nothing is black inside the shroud. That surprised me also. I discovered the muffler was a tad loose, so it doesn't take much..

Well that sure blows holes in my theroy. I just checked, and the bolts are still tight so I highly doubt its a leak but i suppose it could be if the pot metal muffler was tweaked.

 

[jakethesnake]

Mine does the same. I put some good foil duct tape underside. It helps. It’s just the nature of the beast.

 

[Duane(Pa)]

Fatten up the tune? Lower EGT. Foil tape maybe even double layer.

 

[biggerstaff94]

Fatten up the tune? Lower EGT. Foil tape maybe even double layer.

I left the carb settings where the dealer set them. Im gonna see what foil tape does. The hi jet already seems pretty rich already, the low jet seems on point. Itll idle itself out of fuel if i let it. Not sure whats recommend or if it makes a difference but in running the same 40:1 i run in everything else.

 

[jakethesnake]

40:1 sounds like a real good number to me

 

[ChillyB]

For clutch cover burns I welded shut the side discharge and welded a discharge tube into the front corner.

I recall that my top cover had a heavy foil piece on the underside of the cover. Can’t confirm because I sold that saw.

 

[scottr]

Well that sure blows holes in my theroy. I just checked, and the bolts are still tight so I highly doubt its a leak but i suppose it could be if the pot metal muffler was tweaked.

Is this a OEM muffler and is the gasket present ?

 

[biggerstaff94]

Is this a OEM muffler and is the gasket present ?

Yes, oem muffler and a copper gasket i lazer cut out of some .030 copper shim stock.

I drew up a new muffler this morning on cad, im 3d printing a prototype now. Its not as close to the top cover and has 2 front outlets. Ill have pictures in about 5 hours ill want some feedback on. I dont really know about 2 strokes and backpressure, so if you guys think itll work ill make an aluminum version and run it.

Between that and the foil tape itll remedy the burning covers but i want it to flow well. The saw isnt ported but does have smoothed out ports, a plugged decomp valve and a pop up piston.

 

[Mike mike]

Yes I would do a copper shim or a piece of sheet metal between the muffler and the exhaust gasket and then I would get some M3 heat tape and put it on the underside of your air cover top all the way back to the spark plug takes a little time to fit pieces in there Make sure the plastics clean cuz I've done this to my 038 Magnum and my Husqvarna 55 rancher solve the problem of overheating the top cover

 

[biggerstaff94]

So this is what I’m thinking for a muffler.

3/8” port extension
Make the gas go around a divider for some back pressure then exit through 2 1/2” diameter holes that are 5/8 long.

Itll be shorter to get it away from the top cover so that plus foil tape should save it. The ports exit the front so that should save the clutch cover. Itll be regular 6061 aluminum so it should dissipate heat well. Lazer cut copper gasket between the two halfs. What do you guys think, will it make more power than stock?

Dont mind the print quality, i blasted it out quick.

 

[jakethesnake]

I think it looks cool as hell

 

[5155]

If the exhaust pipes stick out further than the bucking spike that might be a problem in big wood.

 

[biggerstaff94]

They shouldn’t, it protrudes 2” from cylinder so itll be a tad thinner than the oem muffler. I need to pull the muffler off and get it in here for a few final dimensions but if its a problem i could burn out bigger dogs or mill the outlets at an angle like a slash cut.