Makita 6421 muffler mods?

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

acp104

ArboristSite Lurker
Joined
Apr 24, 2015
Messages
16
Reaction score
3
Location
NW Illinois
Guys, I've been searching the forum for specific info on modding the 6421 cat muffler for good performance, but haven't had much luck finding anything besides "Open the seam and pull out cat/baffle". I'm thinking this is common mod, so I might not be using the search function right. If not, I'm sorry. I plan to order a BB kit from Weedeaterman soon, and would like to try removing the cat stuff and maybe adding another port to the muffler if recommended. Is removing the internals worth it? Is adding another port beneficial? If this topic has been beat to death, Maybe someone can point me to a related thread or two. Thanks.
 
Thanks for the response. Any idea if a propane plumbers torch will create enough heat to bend the seam, or do you need to use a true cutting torch?
 
I have heard it is not. I used an acetylene torch. High heat is key. You can buy one at Menards for around $40. Map gas probably would work too.
 
I'd try it stock of you have not already. It is quite powerful for only being a 64cc. Mine felt even better after gutting the cat and opening up the muffler a bit. However, I have never run a 7910 so hopefully someone else will chime in.
 
I picked the saw up a couple weeks ago from our local Home Depot rental department after pestering them regularly for about 2 months. I have a Deere CS62 already so my purpose for buying the Makita was to upjug it to have a significantly more powerful saw to run a 24-28 inch bar. I used the new saw to hinge cut some trees for deer bedding areas last weekend, but haven't had the chance to buck any logs with it yet. My buddy helped hinge cut with the CS62 and we swapped saws a couple times. I did feel the Deere was more responsive and it is a couple lbs lighter for a saw of similar displacement. I do want to compare these two saws when bucking a log.
 
Were you using the "rental" 20" bar and the tri link chain that came with it? Even new that chain is junk. I put a nice Stihl RS on decent bar and it is a night and day difference.

However I can understand your wanting to go larger with a similar sized saw that you already own.
 
Red hot is needed so propane plumbers torch or map gas on a plumber torch won't do it. Cutting torch with a small tip/flame is needed.
 
Ahh the CS62/Efco 162/Oleo Mac962!!! Great little saw from yesteryear!

If you can weld thin steel you can just cut off the seam.

7
 
Yep, I like the 62 a lot. I'm hoping I'll like the Dolmar just as much for my bigger saw once I get'er modded. Struggling with the decision between OEM 79cc cylinder vs cheaper aftermarket big bore. If the big bores all have the compression release in the old location causing me to need a new cover, that will probably make me lean towards OEM.
 
OEM vs BB has been debated allot. i think the consensus is that the oem has a fuzz more power in most cases but quality will always go to the oem. some of the BB kits are flat out junk.
 
Back
Top