Modified muffler wanted for stihl

[samthescam]

If they are in warranty, I wouldn't touch them as it would invalidate the warranty straight away leaving you with no comeback if the saw fails.

 

If the muffler gets a mod then the carb would need a final tune - normally limit caps need to be pulled and refitted - would you do this or me - needing the whole saw to be sent!

 

To be honest, I'd want you todo it all. Both the saws are under warranty so might have to wait a bit for them. Still would be interested in a price so I can take it into account for other saws.

[Cut4fun]

Like you say norm is 80. But testing the 290 more toward 100 when more gains were found. Many I have found like more then norm.

 

You dont know till you keep doing little more at a time.

 

I do the 290 310 390 free for people, it's that freaking easy. But your on the wrong side of the pond. If they bring a beer to swig while doing so is a plus for all of us.

[Cut4fun]

I just checked and a oem muffler can be bought here for $25 USD.

[blazer]

Just looked up the MS390 muffler outlet on stihl, and it shows x2 outlets one for US, AUS & one for peasants - does it make any difference. I'm into engineering but didn't quite get it - leave out screen & drill six holes (what size please) from the manifold or outlet side.

 

My old MS390 is about 10yrs old, so I can go for it. It's always the same with me simple job and I will over complicate it.

 

I have the MS390 and a 266XP always pick up the Husky.

 

Many thanks:thumbup1:

[Cut4fun]

I would have to have one in hand to tell you what drill bits I am using. I drill holes then use a dremel to enlarge them and widen them to my liken. Even the 2 oem slits. Dont forget to open deflector like shown on the 390 thread.

 

Here is a stock muffler I pulled pic off net and added what to add in white.

 

Now it is very easy to just look and drill the holes to fit inside the baffle which really is the saw waker upper IMO and the added smaller holes on the outside baffle.

 

Carb tune afterwords which will be richer for sure on H side. Make sure idle is fine afterwords too.

[blazer]

Many thanks 'Cut4fun' that clears it up. Haven't done alot with 2strokes over the years, only remember the exhaust back pressure hold back the gas mix for the next firing as with reverse cone exhaust pipes on race bikes and seeing pictures of them being tuned by cutting the lenght of the exhaust pipe - so do you tune by making the holes bigger and try to stop at peak power. I can proportion the holes needed from your picture - thanks again:thumbup1:

[normandylumberjack]

Thats a fantastic way of explaining the mod. I now understand too. will let you know how it goes.

[blazer]

OK Normandylumberjack you go first and if I don't see a 'dear Spud' post, I will do mine:sneaky2:

 

No only joking, cut4fun really cleared up what to do. I looked on Mistersolutions Stihl spares and it lists x2 muffler covers one US (as seen on cut4fun's post) and one for UK, next time I put an order in will inc the US cover. I will do my MS390 being old and the twin port mod to the MS460 later.

[spudulike]

OK Normandylumberjack you go first and if I don't see a 'dear Spud' post, I will do mine:sneaky2:

 

No only joking, cut4fun really cleared up what to do. I looked on Mistersolutions Stihl spares and it lists x2 muffler covers one US (as seen on cut4fun's post) and one for UK, next time I put an order in will inc the US cover. I will do my MS390 being old and the twin port mod to the MS460 later.

 

Bang goes the Christmas card from the neighbours once you fire that up:thumbup:

[blazer]

Bang goes the Christmas card from the neighbours once you fire that up:thumbup:

 

There was a 80% chance of getting a Xmas card after my son fitted sports cans to his XT660R - he thinks baffles are for girls, reduced to 40% when we left him at home for our hols, he asked if he could have a few friends around for a quite drink - yep they called the police out at 3:00am. Now it's > 10% when I emptied my saws by firing up x6 saws at the same time. trying to find a Xmas card that makes chainsaw noise to send to them:001_tt2:

 

Back to MS390 as it has a muffler outlet plate with x3 screws over the exhaust, I will make up a spacer plate with less holes so it can be refitted back to std and re-tuned back so the saw can still be used in gardens. Most of my saw work is on a large country estate.