MS260 Muffler Mods. What do you think?

[UK Rich]

Evening people. I was bored yesterday, and after looking at the utterly useless looking UK spec 260 outlet, I thought something had to give. They all seem to have 2 little 'fish gill' type slots on the B&C side. Do you get these on your side of the sea? Sorry for the less than ideal quality pictures. Sponsored by Nokia.

So I brazed it up and cut a rectangular shape hole on the other side.

Then finished it with a homemade deflector.

Bit rough and ready, but then, so am I.

What do you think. Win or Fail?

Rich.

 

[Trigger-Time]

Looks like a win to me!.......but I would have left the org. holes also.
It would have been a duel port




TT

 

[blsnelling]

That'll work fine, as long as it still idles fine. Looks like a lot of open surface area.

 

[UK Rich]

I thought about doing the same on the other side too, but there's not a great deal of space. I have a few spare covers so i'll probably mess about with different set ups.

Still not overly impressed with the set up (big jump between this and my 660). Only running a 15" bar, so may jump to an 8pin sprocket. Or maybe pull it apart and do some porting. Maybe both...

 

[UK Rich]

Brad, the picture is a little deceiving. The hole is probably only 3/4 or that deflector. I left some meat in there to play around with. Plus, I'll sort some kind of screen, to stop debris.

 

[stihlboy]

Looks like a win to me!.......but I would have left the org. holes also.
It would have been a dual port




TT

The last post he made,

gary was a great guy, knew his stuff too. even his last post was giving positive help to others.

you will be greatly missed! By me and by the A.S community. You were an asset to this site.

 

[Zippy]

I'm rebuilding an 026 at the moment - well waiting for parts more than rebuilding.

Once it's up and running good I'm thinking of trying a muffler mod.

Is there a rule of thumb to the area the exhaust outlet should be opened to?

I understand that some back pressure can be good for performance (example tuned 2 stroke race bike exhausts) but don't know about chainsaw mufflers.

What happens if you open them up too much - do you get poor idling and a loss of power?

UK Rich - how is your 026 running - did you notice much difference after opening the muffler?

 

[Frank Boyer]

On the USA 260's there is a single 5/16" hole in the baffle in the cover. Drill that hole to 3/8" or 7/16" and add 2 more hole the same size. The extra 2 holes really wake up a 260. Readjust the carb after the mod. Andy/Lakeside posted this a few years ago. It is a 15 minute mod that works.