Gutting the Dolmar 7910 Muffler

In the pic above that Carl posted that would be the cylinder side.

 

Hey if you didn't I won't say that's wrong either. Lol. Would of maybe said I reccomend it for support. Lol. Good thread my man.

 

Thanks bud! Yeah I tend to be a little heavy handed when tightening screws and bolts. I was worried about crushing the muffler so I threw it back in there.

 

Now that I own a 6421, I've done a bit more reading on muffler mods and 79 or 84 cc top ends. In your experience, do you think that if you just uncrimped the bottom flat, that you'd be able to pull the muffler apart easier? Maybe start with that bottom flat, then work up the sides a little?


I'll have to look for aftermarket ones, to weigh the costs.

 

I think it would depend on how tight the crimp is on the muffler. On this one it was really tight. Also the stupid reverb pipe in the 7910 is somewhat attached to the to the mounting posts. The 6421 muffler is different inside though so you might get away with it.

 

IMO it's just easier to uncrimp it all. The 6421 is a little more difficult as it's a stainless muffler. Where the 7910 is more of a galvanized muffler. Once inside the 6421 however the guys just fall out and can be thrown away. Then recrimp.

 

Barcroftb showed ya the 7910 muffler. So maybe this will help the 6421 guys.
Left 7900. Right 6421 cat muffler.

 

Picture is verticle? Which one is the one on left and right, not sure how you had it orientated when you took the pic?

 

That would be the 7900 on top and the 6421 on the bottom.

 

I just remembered you said one was stainless, I guess I could of gone back through the posts and figured out which one was stainless and then would know as wee. But thanks for the clarification

 

Here they are opened up bottom pic is the 6421.

 

I tac weld in the little spacer.

 

Throw all this is the trash can. Lol.

 

However. These don't need to come out. I just do it for weight reduction.

 

Now it will be a bit as I bolt the back half to the cylinder and port the exhaust. Muffler mod them. Then I'll clean them all up so no shavings are in the muffler and out them back together.

 

As you can see I already did some grinding on the cylinder. But her she is bolted back up.

 

And the finished aftermath. Lol.

 

It looks like the 7910 muffler is physically a bit bigger than the 6421 muffler.

 

It's different shaped. Lol. But it maybe with that corner squared off.