6400 cat muffler gut

[MS460WOODCHUCK]

Would anyone that has done this with good results be willing to do this for me if I paid for it to be done. I just don't think I could get it apart and sealed back up good. I would hate to melt parts because of the seam leaking.

 

[cgraham1]

muffler split and body tools ready. View attachment 398700

You also might try MillerModSaws... He recently did a thread on a different forum showing how to gut the cat muffler on a Dolmar.

 

[Lootbug]

Here's a write up (with pics) of how I did a few 6421's. The second and third one I just left out the middle heat shield plate entirely. Worked out very well. Don't be afraid to give it a go, toughest part is getting it uncrimped.

http://www.arboristsite.com/community/threads/de-catting-the-makita-6421.264282/#post-4979868

 

[fordf150]

They aren't hard. If your going to pay to have it done and pay for shipping it both ways just buy the 7900 muffler.

 

[nmurph]

They aren't hard. If your going to pay to have it done and pay for shipping it both ways just buy the 7900 muffler.

This ^^^^^^ is the answer.

 

[jughead500]

I can do it for you.It may not look perfect after I uncrimp it.Can use the Experience just pay shipping.Shoot me a PM.

 

[LogSawyer74]

I've got a brand new 6400 cat muffler I removed and replaced with a non-cat when I was building my 7900 a few years back. If you want to pay shipping, I'll send it to you to practice on...... Don't think I'd ever have any use for it.

 

[fordf150]

I can do it for you.It may not look perfect after I uncrimp it.Can use the Experience just pay shipping.Shoot me a PM.

they arent bad. First one will take you 30-40 minutes to do a nice job. easiest way is to uncrimp the straight side of the muffler and slide it apart. If i remember the next one i do i will make a video of uncrimping it.

 

[jughead500]

I've got a brand new 6400 cat muffler I removed and replaced with a non-cat when I was building my 7900 a few years back. If you want to pay shipping, I'll send it to you to practice on...... Don't think I'd ever have any use for it.

Sure i'll try it.

 

[jughead500]

they arent bad. First one will take you 30-40 minutes to do a nice job. easiest way is to uncrimp the straight side of the muffler and slide it apart. If i remember the next one i do i will make a video of uncrimping it.

Done several by uncrimping but always like to keep up practice on stuff.done a 017 muffler without uncrimping the other day.10 minutes with drill and dremel and i was done.

 

[fordf150]

here is a 6400 cat muffler and what it takes to gut them. Its no wonder the 6400 is heavier than the 7910. 4 layers of heavy stainless plus a cat is what makes up the 6400 muffler.

 

[fordf150]

remove the cage but leave the reinforcements that are welded to the tubes. That way there is no space to make up inside of the muffler. I didnt enlarge the opening since i think it is already plenty big for a 6400 and I dont like overly loud saws just for the sake of them being loud. I also like to keep the spark arrestor intact on all outlets since me and many other people just haul our saws in the bed of a truck and i am always scared of junk blowing in through the opening.

 

[fordf150]

Put it all back together leaving out the 2 center layers of the muffler. there is no space to make up since those center layers go clear out to the crimped edge. you do have to crimp the whole way around the muffler since we removed 2 layers that were under the crimp. Here is what came out of the muffler and the gutted muffler.

 

[Poleman]

GREAT JOB!! Nate!!!!!

Just did one two weekends ago.....suire not as fast as you. I have trouble heating and uncrimping the crimp.... After that I'm good.

Had the same issues with a 7900 muffler but easier than the 6400 because of less layers....they got a lot of stuff crammed in those. Quite a bit of weight differenct too when done.

 

[Ambull01]

You guys make it look/sound easy. I too am a bit afraid to try it. If I mess it up I'll have three non running chainsaws on my hands.

 

[fordf150]

6400 muffler seems like thicker steel too. that crimp is tough on them. this one wasnt so quick. took me more than a week to get time to do it.

You guys make it look/sound easy. I too am a bit afraid to try it. If I mess it up I'll have three non running chainsaws on my hands.

if you screw it up you just have to order a new muffler. no biggie. heating it up is the only difficult part. you have to have it red hot to bend it but its sheet metal so there is fine line between red hot and melted

 

[Poleman]

I agree...the 6400 seemed tougher.....and cherry red is a must or your not bending it.
Overall not hard just gotta be smarter than the muffler!! Lol

 

[Ambull01]

if you screw it up you just have to order a new muffler. no biggie. heating it up is the only difficult part. you have to have it red hot to bend it but its sheet metal so there is fine line between red hot and melted

That's the part I'm nervous about. I have a knack for using too much torque and breaking bolts/screws, taking stuff apart and forgetting how to put it back together, etc. I may need to order a muffler before I try this.