muffler mods on an xl76

[starter]

Is it worth squeezing a little more performance out of my xl76 by opening up the muffler? I'd like a litlle more power but don't want to go overboard. I've read up a bit and if I understand right would need a little richer mixture setting.

What would be reasonable in terms of opening up the muffler?

Would I need to reset both the idle and high speed mixture?

Any suggestions?

 

[Four Paws]

Is it worth squeezing a little more performance out of my xl76 by opening up the muffler? I'd like a litlle more power but don't want to go overboard. I've read up a bit and if I understand right would need a little richer mixture setting.

What would be reasonable in terms of opening up the muffler?

Would I need to reset both the idle and high speed mixture?

Any suggestions?

Yes, more performance is always better - if it is what you are after! An XL76 sounds like an older Homelite?? Chances are the muffler is pretty open from the factory, but as I am not familiar with the saw...reasonable muffler opening is about 85% of the surface area of the flange/muffler interface on most newer saws.

You are essentially reducing backpressure and allowing the cylinder to breathe better. So, more unburnt fuel will escape through the exhaust that was previously trapped in the cylinder, hence you will need more fuel. The best advice is to tune the saw using a tachometer, or take it to a shop and have them tune it after your muffler mod.

A good place to look would be in the chainsaw forum - search titles only using the words DIY, muffler, mod. You will find many lengthy threads to keep you busy reading - quite a few have pictures of various mods to give you ideas.

Josh

 

[starter]

OK, I'll surf and read more. When you say flange/muffler interface do you mean exhaust port opening area? I.e., compare the area of the exhaust port to the combined area of the restrictor plate holes.

>>> Scratch that question, I've been reading your post in the chainsaw forum and understand more know. <<<

>>> It is an older Homelite, year unknown, no production information on Mike Acres site. <<<

 

[Crofter]

I remember the XL 76s as being pretty loud, so as Four Paws suggests they probably did not have the same degree of restriction that the modern saws surely do. You might not make much gains from opening it up further. Personally I would not put much faith in taking an old saw to a shop to have the carb set by someone who might be used to the high revs of todays saws.

 

[romeo]

There are very low restrictions on that saw. You can just take a screw driver and open up the four vents wider and you can also take out the baffle inside the muffler. These saws like to run super rich.
I wouldn't go crazy with mods, I experimented with one. They make nice classics that sound cool but are along way from a race saw.

 

[romeo]

You can also do this.

Hammer the vents flat and weld them shut, then punch a couple of 1/2 inch holes in the corners. This saw ran better and sounds cool.