Lakeside53's --361 muffler mod w/photos

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Why are you modding a 460? You can go buy a dual port muffler cover from Stihl for that for about $30. Part number 1128 140 0801.

I went to a dealer and was quoted $75. I just left it at that and figured for that I will mod it myself, and didnt bother asking other dealers. I will call another dealer tommorow.
 
I bought a used one, ebay $15, used it to mod and put the new
one up for safe keeping.

No screen though.
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Not much has been said about this mod?? I assume it's not as good as Lakeside's??? I would be a lot simpler to do... No screen, but the "slits" wouldn't be that prone to letting in debris. Has no one else done this?
 
I just took my muffler of my 460 to do the mod. Do I drill out a hole in the cover of the muffler, or do I widen the side by the spark arrestor? I think it would be easyer to drill out the cover instead of the side of the muffler.

If you should decide to drill out the existing port, you will still be able to use the screen. A little harder than just drilling holes, but you get to utilize the screen. I have done it both ways, and can't tell any difference in performance, even tho one muffler has the baffle plate inside, and the other one doesn't.
Can anyone tell me if the one w/o a baffle is an older model muffler, or just a different one?? Stihl has 3-4 different models listed for the 460.
 
the new and improved 630 muffler mod.first post with the new camera.

Looks good and I bet it rips too. I like the angled pipes better than the straight. The straight looked like they would hit the log when cutting. What is the dia of the pipes. Conduit??
 
3/4 galvanized conduit. good eye. welded with a mig. then alot of grinding. i'm doing the 670 over again the same but with the bigger pipe. the original is crazy loud when you are bucking a big tree when the exhaust gets into the wood and bounces it back to ya. run half and half 108 race gas and 91 premium with lucas mix, smells gr8 but the loudness kills your ears even with plugs in. lol
 
at the beginning of this thread, it is stated that you shouldnt exceed 80-85% of the exhaust port diameter, when porting your muffler. does anyone take the time to measure the exhaust port and do the math or are ya'll just eye ballin it an making sure that your below the 100% mark?
 
my 630 is definately just below the 100% mark but the 670 is about 115%
runs gr8 a little hard to idle buthas tons of power.
 
Not much has been said about this mod?? I assume it's not as good as Lakeside's??? I would be a lot simpler to do... No screen, but the "slits" wouldn't be that prone to letting in debris. Has no one else done this?

I would also like to know about this way. Looks very nice. How did you get the slits in the muffler?
 
does anyone take the time to measure the exhaust port and do the math or are ya'll just eye ballin it an making sure that your below the 100% mark?

Always. It's given me an opportunity to brush up on my basic geometry. :hmm3grin2orange:

You can't be exact, but if the 80% point comes in at .70, I'll round it down and use a pipe with 5/8" diameter (.625) ID rather than going up to a 3/4" (.750).
I may lose an imperceptible amount of power, but it better than going too far. :cry:
 
some pics of the new 670 mod.
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have a bit of grinding and blending left to do. then paint.
 
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Always. It's given me an opportunity to brush up on my basic geometry. :hmm3grin2orange:

You can't be exact, but if the 80% point comes in at .70, I'll round it down and use a pipe with 5/8" diameter (.625) ID rather than going up to a 3/4" (.750).
I may lose an imperceptible amount of power, but it better than going too far. :cry:

according to my math 5/8 pipe will have a free area of .31 sq. in. if ID of the tube is .625 3/4 will be .442 sq in if ID is .750 so you would need two 5/8 pipes to get around 80% of the .70 port area which is .56
 
according to my math 5/8 pipe will have a free area of .31 sq. in. if ID of the tube is .625 3/4 will be .442 sq in if ID is .750 so you would need two 5/8 pipes to get around 80% of the .70 port area which is .56

Congratulations! You get a gold star for math! :clap:

But you missed my point.

I should have been clearer. When all your math is done, you decide your theoretical saw needs a pipe with a .70 ID to do your 80% job (big saw). Since no stock, off-the-shelf pipe has an ID of .70, then I would go with the .625 rather than the .750 pipe.

All I was advocating is to err on the low side rather than the high side.

The MS280 I just muffler-modded had all 54.7 ccs of displacement exhausting through a single .325 hole in the muffler! I'm surprised it didn't whistle! :) Even opening the hole to 50% of the exhaust port would have made a huge improvement. For a work saw you can achieve great gains without bumping up against the high-side ceiling.
 
I cut a small rectangular hole in the muffler of my new MS290 and opened up the final exit just a little .I can hear and feel a slight difference. I am afraid to go any more till Im sure of how to tune the carb. the H is already at the stop. I have searched the site with out finding any details on how to remove the stops .can someone post some pics and a step by step instructions on how to do this
thanks Mick
 
I cut a small rectangular hole in the muffler of my new MS290 and opened up the final exit just a little .I can hear and feel a slight difference. I am afraid to go any more till Im sure of how to tune the carb. the H is already at the stop. I have searched the site with out finding any details on how to remove the stops .can someone post some pics and a step by step instructions on how to do this
thanks Mick

Mick, others here do it differently than myself... But heating a small nail or screw (or anything small and metal), and melting the tabs off works pretty good. Take your time, and nothing will get melted that shouldn't be.

Like I said, others do it different.
 

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