Hey guys,

I bought a used 2013 S40 about two months ago with just under 1K miles (it's my second bike, I've also got a 2015 CB500F) and it's the first vehicle I've ever owned with an old-school carburetor and air cooled engine.  I've spent some time before buying and since owning the bike on these forums, but it's almost summer and I want to get serious about her very soon

Anyway, I really love this bike (and my girlfriend does too) but just like everybody else, I am just not happy with the stock muffler sound.  I've read over the Dyna thread several times but none of the images will show up anymore so I'm not sure what I'm looking for on ebay to purchase.  I really don't want to do too many mods to it, but the exhaust (and I'm guessing a rejet) is a must.

I'm not afraid of using tools or getting my hands dirty, but I also want to find the simplest, least time consuming method to attack this with.  I'm not super worried about backfires or anything like that, I just want it to run well and I don't want it to sound like a scooter anymore!

Also, the previous owner did not have the manual (WTF?) so I'm wondering if I should pony up for that or just buy a service manual and skip it all together.

Any pointers in the right direction would just make my day!  Thanks in advance!  Also, sorry if I missed some very obvious posts, but I swear I looked!

Don't bother with an owners manual.....buy a Clymers manual.

The muffler job is easy if you buy a RYCA adapter.....other methods are more labor intensive.

You are looking for a Harley DYNA muffler.  I prefer them without a catalytic converter......and you have to make sure that folks haven't drilled or knocked out the center plug to make it louder.

You "DON'T" want to buy mufflers that have the cross tube....like this:
https://www.ebay.com/itm/Harley-Davidson-FXD-1450-DYNA-Used-Original-Right-Le...

These would work:
https://www.ebay.com/itm/Nice-Harley-Davidson-Dyna-Mufflers-FXD-FXDB-FXDL-FXD...

https://www.ebay.com/itm/2002-harley-davidson-dyna-low-rider-fxdl-Mufflers/29...

https://www.ebay.com/itm/Motorcycle-Harley-Davidson-Stock-2005-Dyna-Mufflers-...

I don't know what year came with the catalytic converter....I suspect California may have got them sooner than other states.

You can search and find some cheaper.....I just set my filter for $5 - $100 and did a quick search.  You can email the seller to find out if the baffles are intact and if the wording states the catalyst is in the muffler (or he can look inside the inlet and see if there is a bunch of tiny holes just inside the front of the muffler....or one big hole).

If you get a nice set....you can easily sell the extra one on this forum.

I agree with using an adapter with about a 6 degree bend.  I got one made and fitted at the local muffler shop. Still able to use a single bolt on the dyna rail which is enough. The straps on the muffler are because this particular dyna came with factory heat shield.

I have a stock air filter, I put a 20 pilot on and adjusted the needle clip, but I ended up putting the needle clip back to stock because it was running too rich. I'm at sea level in a warm spot. Also when I got the bike simply adjusting the air/fuel mix screw made the bike run noticeably better.

Dave:  Thanks for all the info, and especially the links!  Made an offer on the first listing, we'll see how that goes.  There's a local motorcycle parts store in my town too, I think I'll go check out what they've got as well.

In the mean time I'll be removing the cover from the air/fuel screw and toying around with that a bit.

eau de sauvage:  I'll definitely check out the adapter.

verslagen1:  Man I would love to ride out to Kerrville!  Have lots of friends who go out there every year to party!  I'll definitely let you know if I ride out!  Thanks for the tip on the manual BTW.

at the risk of disagreeing with the far more knowledgeable than I, Batman, I'd suggest 1200 to be a more appropriate final idle setting for this bike. It easily stalls at very low rpms.

Regarding the idle setting. My bike is set at around 1800 RPM and it doesn't sound fast at all. (I do have a Tach) I'm not sure if this is why I very rarely get a backfire on gear changes, 1100 RPM sounds a bit slow to my ear and I'm sure it is not too slow but 1800 certainly doesn't sound fast. Our problem with cam lubrication is reason enough for me.

Justin, I will have to check. It is very hilly where I live so will have find a flat piece of road.

It's not even almost something anyone would know, so, relax and work through it.

adjust the fuel mix screw to you obtain the fastest idle , then reset the idle speed back to 1000+ rpm .

Turn it slowly and if you screw it in Tight you can screw up the brass tip.